diff --git a/404.html b/404.html index 521171f1c9..25ddf2e15e 100644 --- a/404.html +++ b/404.html @@ -15,7 +15,7 @@ - + @@ -51,7 +51,7 @@ GitHub (opens new window) GitHub - (opens new window)

404 - Not Found

How did we get here?
+ (opens new window)

404 - Not Found

That's a Four-Oh-Four.
Take me home.
- + diff --git a/assets/js/10.c1c0e738.js b/assets/js/10.49750700.js similarity index 99% rename from assets/js/10.c1c0e738.js rename to assets/js/10.49750700.js index 5a736ce8b2..41352392af 100644 --- a/assets/js/10.c1c0e738.js +++ b/assets/js/10.49750700.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[10],{326:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_complete_app.c74da859.png"},327:function(t,a,s){t.exports=s.p+"assets/img/default_flutter_app.31b31721.png"},328:function(t,a,s){t.exports=s.p+"assets/img/assets_section.b43d75e9.png"},329:function(t,a,s){t.exports=s.p+"assets/img/folder_structure.b2750bd6.png"},330:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_title.e4e3484a.png"},331:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_tutorial_screen_mnemonic.df703b77.png"},332:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_tutorial_screen_createwallet.3b052736.png"},333:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_get_balance.bfdf9ced.png"},334:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_get_address.5db2e3cc.png"},335:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_get_restore.db8e7e55.png"},336:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_send.1688372b.png"},405:function(t,a,s){"use strict";s.r(a);var n=s(7),e=Object(n.a)({},(function(){var t=this,a=t._self._c;return a("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[a("h2",{attrs:{id:"introduction"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#introduction"}},[t._v("#")]),t._v(" Introduction")]),t._v(" "),a("p",[a("code",[t._v("bdk-flutter")]),t._v(" is the "),a("strong",[t._v("Bitcoin Dev kit")]),t._v("'s "),a("strong",[t._v("Flutter")]),t._v(" library which enables building bitcoin applications for Android and iOS mobile platforms. Using "),a("code",[t._v("bdk-flutter")]),t._v(" is similar to using any other Flutter module. Just do "),a("code",[t._v("flutter pub add bdk_flutter")]),t._v(" and you are ready to code! This is the first tutorial on how to use "),a("code",[t._v("bdk-flutter")]),t._v(", more coming soon, make sure to "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior",target:"_blank",rel:"noopener noreferrer"}},[t._v("follow"),a("OutboundLink")],1),t._v(" to be notified of new ones. There will also be a "),a("strong",[a("code",[t._v("bdk-flutter")])]),t._v(" focused Livestream on "),a("a",{attrs:{href:"https://www.twitch.tv/bitcoindevelopers",target:"_blank",rel:"noopener noreferrer"}},[t._v("Twitch"),a("OutboundLink")],1),t._v(" on the Bitcoin Developers "),a("a",{attrs:{href:"https://www.youtube.com/channel/UCUq_ZdezVWKPvkWRicAYxLA/videos",target:"_blank",rel:"noopener noreferrer"}},[t._v("YouTube Channel"),a("OutboundLink")],1),t._v(" so make sure to subscribe.")]),t._v(" "),a("p",[t._v("This tutorial will explore "),a("code",[t._v("bdk-flutter")]),t._v(" usage and the API it provides. This guide will walk through the development process and code for making a bitcoin application. The bitcoin application we create will be a non-custodial HD Wallet. The application will have the functionality to create a new wallet or restore from a known mnemonic seed phrase. This application will also be able to interact with the bitcoin network to sync UTXOs from new blocks and broadcast transactions.")]),t._v(" "),a("p",[t._v("The tutorial will focus on bitcoin concepts and "),a("code",[t._v("bdk-flutter")]),t._v(" API. So it will gloss over Flutter and Dart. If you are interested in learning more about Flutter and Dart please refer to the Flutter "),a("a",{attrs:{href:"https://flutter.dev/learn",target:"_blank",rel:"noopener noreferrer"}},[t._v("learning portal"),a("OutboundLink")],1),t._v(". The code for this tutorial is available on the "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter-quickstart",target:"_blank",rel:"noopener noreferrer"}},[t._v("LtbLightning GitHub"),a("OutboundLink")],1)]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(326)}}),t._v(" "),a("h3",{attrs:{id:"prerequisites"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#prerequisites"}},[t._v("#")]),t._v(" Prerequisites")]),t._v(" "),a("p",[t._v("To use "),a("code",[t._v("bdk-flutter")]),t._v(" in a Flutter App, a Flutter development environment is required. Please refer to resources out there on the internet if you need to set this up, here is one of many good resources to guide you on "),a("a",{attrs:{href:"https://docs.flutter.dev/get-started/install",target:"_blank",rel:"noopener noreferrer"}},[t._v("environment setup"),a("OutboundLink")],1)]),t._v(" "),a("h3",{attrs:{id:"bitcoin-basics"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-basics"}},[t._v("#")]),t._v(" Bitcoin Basics")]),t._v(" "),a("p",[t._v("The bitcoin concepts used in this blog post are detailed and explained very well in external bitcoin resources. Here are some links for reference:")]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("p",[t._v("Now let's jump into Bitcoin Dev Kit")]),t._v(" "),a("h2",{attrs:{id:"bitcoin-dev-kit-and-bdk-flutter"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-dev-kit-and-bdk-flutter"}},[t._v("#")]),t._v(" Bitcoin Dev Kit and bdk-flutter")]),t._v(" "),a("p",[a("code",[t._v("bdk-flutter")]),t._v(" is "),a("strong",[t._v("Bitcoin Dev kit")]),t._v("'s "),a("strong",[t._v("Flutter")]),t._v(" library for building Bitcoin apps in "),a("strong",[t._v("Flutter")]),t._v(".\nIt encapsulates all of the low-level APIs and methods for BDK and exposes them in a Flutter context. 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"),a("code",[t._v("bdk-flutter")]),t._v(" can be used like any other Flutter library and is available on "),a("a",{attrs:{href:"https://pub.dev/packages/bdk_flutter",target:"_blank",rel:"noopener noreferrer"}},[t._v("pub.dev"),a("OutboundLink")],1)]),t._v(" "),a("h2",{attrs:{id:"getting-started"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#getting-started"}},[t._v("#")]),t._v(" Getting Started")]),t._v(" "),a("p",[t._v("Although we won't delve deep into Flutter we will focus more on bitcoin and "),a("code",[t._v("bdk-flutter")]),t._v(", however, some rudimentary Flutter setup is required, especially a basic Flutter app to add our code.")]),t._v(" "),a("p",[t._v("start by creating a new Flutter project.")]),t._v(" "),a("p",[a("code",[t._v("flutter create bdk-flutter-quickstart")])]),t._v(" "),a("p",[t._v("Once done let's "),a("code",[t._v("cd")]),t._v(" into the new project directory and run the basic Flutter app that's created")]),t._v(" "),a("div",{staticClass:"language-shell extra-class"},[a("pre",{pre:!0,attrs:{class:"language-shell"}},[a("code",[a("span",{pre:!0,attrs:{class:"token builtin class-name"}},[t._v("cd")]),t._v(" bdk-flutter-quickstart\nflutter run\n")])])]),a("p",[t._v("This should start building the app and then launch the app in a simulator. 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decoration"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("InputDecoration")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n hintText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Enter your mnemonic"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* Send Transaction Buttons */")]),t._v("\n\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),a("p",[t._v("Now we need to add a component to display the output of our method calls and this will also need a "),a("code",[t._v("displayText")]),t._v(" variable to track our method call response. To achieve this add the following code.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// screens/home.dart")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// add this as another state variable under mnemonic")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" displayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// modify the generateMnemonicHandler method to also set mnemonic as displayText")]),t._v("\n\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token 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extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// screens/home.dart")]),t._v("\n\n "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* Result */")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// display the component only if displayText has a value")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ResponseContainer")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("text"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v("displayText "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"No Response"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n")])])]),a("p",[t._v('We should now have a working "Generate Mnemonic" button that displays the new mnemonic')]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(331)}}),t._v(" "),a("p",[t._v("A quick recap, we added a button to call a click handler ("),a("code",[t._v("generateMnemonicHandler")]),t._v(") which calls "),a("code",[t._v("generateMnemonic")]),t._v(" API of "),a("code",[t._v("bdk-flutter")]),t._v(". The click handler also sets the state for the app and also updates the "),a("code",[t._v("displayText")]),t._v(" variable to display the output of the call in the display section. We will follow this pattern for the remaining calls to "),a("code",[t._v("bdk-flutter")]),t._v(".")]),t._v(" "),a("h2",{attrs:{id:"creating-a-wallet"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#creating-a-wallet"}},[t._v("#")]),t._v(" Creating a wallet")]),t._v(" "),a("p",[t._v("Before moving on to creating a wallet, let's add a section at the top to display the balance of the wallet.")]),t._v(" "),a("p",[t._v("To display the balance we will need a state variable to store the balance and a display component to display it. We will also be creating a receive address for the wallet so a state variable will be required for the address as well.")]),t._v(" "),a("p",[t._v("Under the "),a("code",[t._v("mnemonic")]),t._v(" and "),a("code",[t._v("displayText")]),t._v(" state variables, let's add one for "),a("code",[t._v("balance")]),t._v(" and one for "),a("code",[t._v("address")])]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" _HomeState "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("extends")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("State")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Home")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("TextEditingController")]),t._v(" mnemonic "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("TextEditingController")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" displayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" balance"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" address"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("Just below "),a("code",[t._v("/* Balance */")]),t._v(" and above "),a("code",[t._v("/* Result */")]),t._v(" add the following UI components to display the balance. We only want to show the balance when it has a value so we will use a null-aware operator "),a("code",[t._v("??")]),t._v(" for a quick "),a("code",[t._v("null")]),t._v(" check and use "),a("code",[t._v("0")]),t._v(" in case of a "),a("code",[t._v("null")]),t._v(" value.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* Balance */")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BalanceContainer")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n text"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"${balance ?? 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Before creating the "),a("code",[t._v("Wallet")]),t._v(" we need to create a "),a("code",[t._v("descriptor")]),t._v(" object which will be used to generate receive addresses and a "),a("code",[t._v("changeDescriptor")]),t._v(" object to to create change addresses to collect from outgoing transactions.")]),t._v(" "),a("p",[a("code",[t._v("bdk_flutter")]),t._v("'s "),a("code",[t._v("Descriptor")]),t._v(" class has a number of descriptor templates that will help you create a simple wallet.")]),t._v(" "),a("p",[t._v("Let's add some code to create a simple "),a("code",[t._v("wpkh")]),t._v(" descriptor object by using the "),a("code",[t._v("BIP84")]),t._v(" template. This template will create a descriptor in the format "),a("code",[t._v("wpkh(key/84'/{0,1}'/0'/{0,1}/*)")])]),t._v(" "),a("p",[t._v("This descriptor will create receive ("),a("code",[t._v("KeyChainKind.External")]),t._v(") and change descriptor ("),a("code",[t._v("KeyChainKind.Internal")]),t._v(") for a specified mnemonic.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("List")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Descriptor")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" 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as well. The Blockchain object will encapsulate the bitcoin node configuration which the wallet will use for syncing blocks and broadcasting transactions.")]),t._v(" "),a("p",[t._v("Let's add an internal method to create and initialize the "),a("code",[t._v("Blockchain")]),t._v(" object.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("blockchainInit")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token 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punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ElectrumConfig")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n stopGap"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("10")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n timeout"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("5")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n retry"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("5")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n url"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"ssl://electrum.blockstream.info:60002"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n validateDomain"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("false")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),a("p",[t._v("Here we are initializing the "),a("code",[t._v("late")]),t._v(" non-nullable "),a("code",[t._v("blockchain")]),t._v(" variable, by calling the named constructor "),a("code",[t._v("create")]),t._v(", which takes a "),a("code",[t._v("BlockchainConfig")]),t._v(" object.\nThe bitcoin node specified is an Electrum node and we are specifying the url for Blockstream's public Electrum Testnet servers over SSL.")]),t._v(" "),a("p",[t._v("After creating the "),a("code",[t._v("blockchainInit()")]),t._v(" method, call it from "),a("code",[t._v("createOrRestoreWallet()")]),t._v(", so the "),a("code",[t._v("blockchain")]),t._v(" variable gets initialized before the "),a("code",[t._v("wallet")]),t._v(" is created.")]),t._v(" "),a("p",[t._v("Include the following line of code inside "),a("code",[t._v("createOrRestoreWallet()")]),t._v(" just before calling Wallet.create().")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("blockchainInit")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("final")]),t._v(" res "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Wallet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("create")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token 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"),a("code",[t._v("BlockchainConfig.esplora")]),t._v(" has "),a("code",[t._v("ElectrumConfig")]),t._v(" object, "),a("code",[t._v("RpcConfig")]),t._v(" object and "),a("code",[t._v("EsploraConfig")]),t._v(" object, respectively as its parameter.")]),t._v(" "),a("p",[a("strong",[t._v("ElectrumConfig")]),t._v(": This is the object type of "),a("code",[t._v("BlockchainConfig.electrum")]),t._v("'s config that takes a timeout, retry & url as its required parameter.")]),t._v(" "),a("p",[a("strong",[t._v("EsploraConfig")]),t._v(": This is the object type of "),a("code",[t._v("BlockchainConfig.esplora")]),t._v("'s config that takes baseUrl & stopGap as its required parameter.")]),t._v(" "),a("p",[a("strong",[t._v("RpcConfig")]),t._v(": This is the object type of "),a("code",[t._v("BlockchainConfig.rpc")]),t._v("'s config that takes url, network, & walletName as its required parameter. If "),a("code",[t._v("Rpc Blockchain")]),t._v(" has its authentication values inside a cookie file, please pass in cookie path as authCookie parameter, or you can pass in rpc username and password using "),a("code",[t._v("UserPass")]),t._v(" class.")]),t._v(" "),a("p",[t._v("Refer to the readme for a complete list of options for "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter#createwallet",target:"_blank",rel:"noopener noreferrer"}},[t._v("createWallet()"),a("OutboundLink")],1)]),t._v(" "),a("h2",{attrs:{id:"utxos-and-balance"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#utxos-and-balance"}},[t._v("#")]),t._v(" UTXOs and balance")]),t._v(" "),a("p",[t._v("With the "),a("code",[t._v("Wallet")]),t._v(" and "),a("code",[t._v("Blockchain")]),t._v(" created, we can now add methods to sync UTXOs and compute balance.")]),t._v(" "),a("p",[a("code",[t._v("Wallet")]),t._v(" has a "),a("code",[t._v("sync")]),t._v(" method to sync all UTXOs belonging to the wallet using the "),a("code",[t._v("Blockchain")]),t._v(" object. Once the wallet sync is complete balance is computed and "),a("code",[t._v("getBalance")]),t._v(" can fetch the balance.")]),t._v(" "),a("p",[t._v("Earlier we have already added a variable for "),a("code",[t._v("balance")]),t._v(". Now we will add buttons to call "),a("code",[t._v("sync")]),t._v(" and "),a("code",[t._v("getBalance")]),t._v(". Just below the Create Wallet button let's add two buttons as follows:")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("SubmitButton")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v(" text"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Sync Wallet"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n callback"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token 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punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n")])])]),a("p",[t._v("Let's add two internal functions for syncing UTXOs and compute balance.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("getBalance")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token 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')]),a("span",{pre:!0,attrs:{class:"token interpolation"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("${")]),a("span",{pre:!0,attrs:{class:"token expression"}},[t._v("balanceObj"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("total"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("toString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("print")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("res"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token 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res"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("syncWallet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n wallet"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("sync")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("blockchain"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("We should now be able to create a wallet, sync UTXOs, and get the balance")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(333)}}),t._v(" "),a("p",[t._v("We can use a public testnet faucet to send testnet coins to the wallet and check that the UTXO sync and balance fetch are working correctly. Before we do that add one more method to generate a new address we can then use this address to get testnet coins from a faucet.")]),t._v(" "),a("p",[t._v("Let's use the "),a("code",[t._v("address")]),t._v(" variable that was created before for this, we need to add a button for "),a("strong",[t._v("Get Address")]),t._v(" and an internal function to call "),a("code",[t._v("Wallet")]),t._v(" and create a new address. Let's do the following")]),t._v(" "),a("p",[t._v("Add a new "),a("code",[t._v("getNewAddress")]),t._v(" function below the "),a("code",[t._v("syncWallet()")]),t._v(" function:")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("getNewAddress")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n 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punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n\n")])])]),a("p",[t._v("We should now be able to send a transaction as long as there is sufficient balance.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"25%"},attrs:{src:s(336)}}),t._v(" "),a("h2",{attrs:{id:"conclusion"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#conclusion"}},[t._v("#")]),t._v(" Conclusion")]),t._v(" "),a("p",[t._v("The App we created can be built and distributed for both iOS and Android thus sharing a code base and reducing development time. The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by "),a("code",[t._v("bdk-flutter")]),t._v(" allowing us to focus on the product, functionality, and user journey. This is how "),a("code",[t._v("bdk")]),t._v(" and "),a("code",[t._v("bdk-flutter")]),t._v(" intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while "),a("code",[t._v("bdk")]),t._v(" handles bitcoin complexity.")]),t._v(" "),a("p",[a("code",[t._v("bdk-flutter")]),t._v(" intends to expose functionality and APIs from "),a("code",[t._v("bdk")]),t._v(" which has a wide variety of APIs with granular details allowing for many interesting use cases to be implemented. "),a("code",[t._v("bdk-flutter")]),t._v(" and "),a("code",[t._v("bdk")]),t._v(" are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.")]),t._v(" "),a("p",[t._v("Stay tuned for more APIs and enhancements coming to "),a("code",[t._v("bdk-flutter")]),t._v(" in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of "),a("code",[t._v("bdk-flutter")]),t._v(".")]),t._v(" "),a("p",[t._v("In the meantime keep in touch with the project by following us on "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter",target:"_blank",rel:"noopener noreferrer"}},[t._v("GitHub"),a("OutboundLink")],1),t._v(" and "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior",target:"_blank",rel:"noopener noreferrer"}},[t._v("Twitter"),a("OutboundLink")],1)]),t._v(" "),a("h4",{attrs:{id:"references"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#references"}},[t._v("#")]),t._v(" References:")]),t._v(" "),a("ul",[a("li",[a("a",{attrs:{href:"https://github.com/bitcoindevkit",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk-flutter"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter-quickstart",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk-flutter-quickstart GitHub Repository"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://docs.flutter.dev/get-started/install",target:"_blank",rel:"noopener noreferrer"}},[t._v("Setup Flutter Development Environment"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("li",[t._v("Testnet Faucet: "),a("a",{attrs:{href:"https://coinfaucet.eu/en/btc-testnet/",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://coinfaucet.eu/en/btc-testnet/"),a("OutboundLink")],1),t._v(" or "),a("a",{attrs:{href:"https://bitcoinfaucet.uo1.net",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://bitcoinfaucet.uo1.net"),a("OutboundLink")],1)])])])}),[],!1,null,null,null);a.default=e.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[10],{336:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_complete_app.c74da859.png"},337:function(t,a,s){t.exports=s.p+"assets/img/default_flutter_app.31b31721.png"},338:function(t,a,s){t.exports=s.p+"assets/img/assets_section.b43d75e9.png"},339:function(t,a,s){t.exports=s.p+"assets/img/folder_structure.b2750bd6.png"},340:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_title.e4e3484a.png"},341:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_tutorial_screen_mnemonic.df703b77.png"},342:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_tutorial_screen_createwallet.3b052736.png"},343:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_get_balance.bfdf9ced.png"},344:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_get_address.5db2e3cc.png"},345:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_get_restore.db8e7e55.png"},346:function(t,a,s){t.exports=s.p+"assets/img/bdk_flutter_send.1688372b.png"},406:function(t,a,s){"use strict";s.r(a);var n=s(7),e=Object(n.a)({},(function(){var t=this,a=t._self._c;return a("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[a("h2",{attrs:{id:"introduction"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#introduction"}},[t._v("#")]),t._v(" Introduction")]),t._v(" "),a("p",[a("code",[t._v("bdk-flutter")]),t._v(" is the "),a("strong",[t._v("Bitcoin Dev kit")]),t._v("'s "),a("strong",[t._v("Flutter")]),t._v(" library which enables building bitcoin applications for Android and iOS mobile platforms. Using "),a("code",[t._v("bdk-flutter")]),t._v(" is similar to using any other Flutter module. Just do "),a("code",[t._v("flutter pub add bdk_flutter")]),t._v(" and you are ready to code! This is the first tutorial on how to use "),a("code",[t._v("bdk-flutter")]),t._v(", more coming soon, make sure to "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior",target:"_blank",rel:"noopener noreferrer"}},[t._v("follow"),a("OutboundLink")],1),t._v(" to be notified of new ones. There will also be a "),a("strong",[a("code",[t._v("bdk-flutter")])]),t._v(" focused Livestream on "),a("a",{attrs:{href:"https://www.twitch.tv/bitcoindevelopers",target:"_blank",rel:"noopener noreferrer"}},[t._v("Twitch"),a("OutboundLink")],1),t._v(" on the Bitcoin Developers "),a("a",{attrs:{href:"https://www.youtube.com/channel/UCUq_ZdezVWKPvkWRicAYxLA/videos",target:"_blank",rel:"noopener noreferrer"}},[t._v("YouTube Channel"),a("OutboundLink")],1),t._v(" so make sure to subscribe.")]),t._v(" "),a("p",[t._v("This tutorial will explore "),a("code",[t._v("bdk-flutter")]),t._v(" usage and the API it provides. This guide will walk through the development process and code for making a bitcoin application. The bitcoin application we create will be a non-custodial HD Wallet. The application will have the functionality to create a new wallet or restore from a known mnemonic seed phrase. This application will also be able to interact with the bitcoin network to sync UTXOs from new blocks and broadcast transactions.")]),t._v(" "),a("p",[t._v("The tutorial will focus on bitcoin concepts and "),a("code",[t._v("bdk-flutter")]),t._v(" API. So it will gloss over Flutter and Dart. If you are interested in learning more about Flutter and Dart please refer to the Flutter "),a("a",{attrs:{href:"https://flutter.dev/learn",target:"_blank",rel:"noopener noreferrer"}},[t._v("learning portal"),a("OutboundLink")],1),t._v(". The code for this tutorial is available on the "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter-quickstart",target:"_blank",rel:"noopener noreferrer"}},[t._v("LtbLightning GitHub"),a("OutboundLink")],1)]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(336)}}),t._v(" "),a("h3",{attrs:{id:"prerequisites"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#prerequisites"}},[t._v("#")]),t._v(" Prerequisites")]),t._v(" "),a("p",[t._v("To use "),a("code",[t._v("bdk-flutter")]),t._v(" in a Flutter App, a Flutter development environment is required. Please refer to resources out there on the internet if you need to set this up, here is one of many good resources to guide you on "),a("a",{attrs:{href:"https://docs.flutter.dev/get-started/install",target:"_blank",rel:"noopener noreferrer"}},[t._v("environment setup"),a("OutboundLink")],1)]),t._v(" "),a("h3",{attrs:{id:"bitcoin-basics"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-basics"}},[t._v("#")]),t._v(" Bitcoin Basics")]),t._v(" "),a("p",[t._v("The bitcoin concepts used in this blog post are detailed and explained very well in external bitcoin resources. Here are some links for reference:")]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("p",[t._v("Now let's jump into Bitcoin Dev Kit")]),t._v(" "),a("h2",{attrs:{id:"bitcoin-dev-kit-and-bdk-flutter"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-dev-kit-and-bdk-flutter"}},[t._v("#")]),t._v(" Bitcoin Dev Kit and bdk-flutter")]),t._v(" "),a("p",[a("code",[t._v("bdk-flutter")]),t._v(" is "),a("strong",[t._v("Bitcoin Dev kit")]),t._v("'s "),a("strong",[t._v("Flutter")]),t._v(" library for building Bitcoin apps in "),a("strong",[t._v("Flutter")]),t._v(".\nIt encapsulates all of the low-level APIs and methods for BDK and exposes them in a Flutter context. To use BDK in Flutter apps only the "),a("code",[t._v("bdk-flutter")]),t._v(" module is required. "),a("code",[t._v("bdk-flutter")]),t._v(" can be used like any other Flutter library and is available on "),a("a",{attrs:{href:"https://pub.dev/packages/bdk_flutter",target:"_blank",rel:"noopener noreferrer"}},[t._v("pub.dev"),a("OutboundLink")],1)]),t._v(" "),a("h2",{attrs:{id:"getting-started"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#getting-started"}},[t._v("#")]),t._v(" Getting Started")]),t._v(" "),a("p",[t._v("Although we won't delve deep into Flutter we will focus more on bitcoin and "),a("code",[t._v("bdk-flutter")]),t._v(", however, some rudimentary Flutter setup is required, especially a basic Flutter app to add our code.")]),t._v(" "),a("p",[t._v("start by creating a new Flutter project.")]),t._v(" "),a("p",[a("code",[t._v("flutter create bdk-flutter-quickstart")])]),t._v(" "),a("p",[t._v("Once done let's "),a("code",[t._v("cd")]),t._v(" into the new project directory and run the basic Flutter app that's created")]),t._v(" "),a("div",{staticClass:"language-shell extra-class"},[a("pre",{pre:!0,attrs:{class:"language-shell"}},[a("code",[a("span",{pre:!0,attrs:{class:"token builtin class-name"}},[t._v("cd")]),t._v(" bdk-flutter-quickstart\nflutter run\n")])])]),a("p",[t._v("This should start building the app and then launch the app in a simulator. So far we have created a basic Flutter project if this doesn't work then refer to the Flutter development setup guide to troubleshoot.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(337),alt:"BDK Flutter Quick Start"}}),t._v(" "),a("h2",{attrs:{id:"setting-up-flutter-app-structure"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#setting-up-flutter-app-structure"}},[t._v("#")]),t._v(" Setting up Flutter app structure")]),t._v(" "),a("p",[t._v("Let's set up a very basic app structure. Let's create an "),a("code",[t._v("assets")]),t._v(" folder in the project root and then add new folders "),a("code",[t._v("widgets")]),t._v(", "),a("code",[t._v("screens")]),t._v(", and "),a("code",[t._v("styles")]),t._v(" inside the existing "),a("code",[t._v("lib")]),t._v(" folder.")]),t._v(" "),a("p",[t._v("Paste the following code in your "),a("code",[t._v("pubspec.yaml")]),t._v(" file, assets section.")]),t._v(" "),a("div",{staticClass:"language- extra-class"},[a("pre",[a("code",[t._v("- assets/\n")])])]),a("p",[t._v("Please make sure your assets section looks like the screenshot below.\n"),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"60%"},attrs:{src:s(338),alt:"BDK Flutter Quick Start"}})]),t._v(" "),a("p",[t._v("Once done let's run a "),a("code",[t._v("get")]),t._v(" command from the pub tool commands, this will get all the required dependencies for our project.")]),t._v(" "),a("div",{staticClass:"language-shell extra-class"},[a("pre",{pre:!0,attrs:{class:"language-shell"}},[a("code",[t._v("flutter pub get\n")])])]),a("p",[t._v("To make this quick you can download the theme, styled widgets and images used in the tutorial from the repository. The "),a("code",[t._v("theme.dart")]),t._v(" file has the theme we will use and this can be taken from "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter-quickstart/blob/master/lib/styles/theme.dart",target:"_blank",rel:"noopener noreferrer"}},[t._v("here"),a("OutboundLink")],1),t._v(" and moved to the styles folder. The "),a("code",[t._v("widgets.dart")]),t._v(" file has the styled widgets we will use and these can be taken from "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter-quickstart/blob/master/lib/widgets/widgets.dart",target:"_blank",rel:"noopener noreferrer"}},[t._v("here"),a("OutboundLink")],1),t._v(" and moved to the widgets folder. The image assets can be taken from "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter-quickstart/tree/master/assets",target:"_blank",rel:"noopener noreferrer"}},[t._v("here"),a("OutboundLink")],1),t._v(" Alternatively, you can write your theme, widgets and use your images if you intend to style the app differently.")]),t._v(" "),a("p",[t._v("In addition to the the theme, widgets and assets. We also need to create a "),a("code",[t._v("screens")]),t._v(" folder and create a "),a("code",[t._v("home.dart")]),t._v(" file inside it, this will be where most of the code will be added.")]),t._v(" "),a("p",[t._v("Once done the file structure should look like this:")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"60%"},attrs:{src:s(339)}}),t._v(" "),a("p",[a("br"),t._v("Locate "),a("code",[t._v("main.dart")]),t._v(" in the project root, this will have the default code added by "),a("code",[t._v("flutter create")]),t._v(", let's delete all contents of "),a("code",[t._v("main.dart")]),t._v(" and replace it with the following code to use "),a("code",[t._v("home.dart")]),t._v(" as our main screen. This will probably crash the app but that's fine, it will be up and running once we add code to "),a("code",[t._v("home.dart")]),t._v(" in the next few steps")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// main.dart")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v("'package:bdk_flutter_quickstart/screens/home.dart'")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v("'package:bdk_flutter_quickstart/styles/theme.dart'")])]),a("span",{pre:!0,attrs:{class:"token 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To achieve this add the following code.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// screens/home.dart")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// add this as another state variable under mnemonic")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" displayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// modify the generateMnemonicHandler method to also set mnemonic as displayText")]),t._v("\n\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token 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The click handler also sets the state for the app and also updates the "),a("code",[t._v("displayText")]),t._v(" variable to display the output of the call in the display section. We will follow this pattern for the remaining calls to "),a("code",[t._v("bdk-flutter")]),t._v(".")]),t._v(" "),a("h2",{attrs:{id:"creating-a-wallet"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#creating-a-wallet"}},[t._v("#")]),t._v(" Creating a wallet")]),t._v(" "),a("p",[t._v("Before moving on to creating a wallet, let's add a section at the top to display the balance of the wallet.")]),t._v(" "),a("p",[t._v("To display the balance we will need a state variable to store the balance and a display component to display it. We will also be creating a receive address for the wallet so a state variable will be required for the address as well.")]),t._v(" "),a("p",[t._v("Under the "),a("code",[t._v("mnemonic")]),t._v(" and "),a("code",[t._v("displayText")]),t._v(" state variables, let's add one for "),a("code",[t._v("balance")]),t._v(" and one for "),a("code",[t._v("address")])]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" _HomeState "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("extends")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("State")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Home")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("TextEditingController")]),t._v(" mnemonic "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("TextEditingController")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" displayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" balance"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("?")]),t._v(" address"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("Just below "),a("code",[t._v("/* Balance */")]),t._v(" and above "),a("code",[t._v("/* Result */")]),t._v(" add the following UI components to display the balance. We only want to show the balance when it has a value so we will use a null-aware operator "),a("code",[t._v("??")]),t._v(" for a quick "),a("code",[t._v("null")]),t._v(" check and use "),a("code",[t._v("0")]),t._v(" in case of a "),a("code",[t._v("null")]),t._v(" value.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* Balance */")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BalanceContainer")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n text"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"${balance ?? "')])]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"} Sats"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* Result */")]),t._v("\n")])])]),a("p",[a("code",[t._v("bdk_flutter")]),t._v(" creates a wallet using output descriptors which define the derivation path to derive addresses and sign transactions. More about output descriptors "),a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("here"),a("OutboundLink")],1),t._v(". Before creating the "),a("code",[t._v("Wallet")]),t._v(" we need to create a "),a("code",[t._v("descriptor")]),t._v(" object which will be used to generate receive addresses and a "),a("code",[t._v("changeDescriptor")]),t._v(" object to to create change addresses to collect from outgoing transactions.")]),t._v(" "),a("p",[a("code",[t._v("bdk_flutter")]),t._v("'s "),a("code",[t._v("Descriptor")]),t._v(" class has a number of descriptor templates that will help you create a simple wallet.")]),t._v(" "),a("p",[t._v("Let's add some code to create a simple "),a("code",[t._v("wpkh")]),t._v(" descriptor object by using the "),a("code",[t._v("BIP84")]),t._v(" template. This template will create a descriptor in the format "),a("code",[t._v("wpkh(key/84'/{0,1}'/0'/{0,1}/*)")])]),t._v(" "),a("p",[t._v("This descriptor will create receive ("),a("code",[t._v("KeyChainKind.External")]),t._v(") and change descriptor ("),a("code",[t._v("KeyChainKind.Internal")]),t._v(") for a specified mnemonic.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("List")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Descriptor")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" 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"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("final")]),t._v(" mnemonicObj "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Mnemonic")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("fromString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("mnemonic"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("final")]),t._v(" descriptorSecretKey "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" 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For database, we can use memory as the database by specifying "),a("code",[t._v("DatabaseConfig.memory()")]),t._v("\nFollowing our pattern of a button, click handler and bdk-flutter API call, Let's add an internal method which will serve as the click handler for the \"Create Wallet\" button. We want to see the output of this call so let's use "),a("code",[t._v("setState()")]),t._v(" to set the "),a("code",[t._v("wallet")]),t._v(" object created and the "),a("code",[t._v("displayText")]),t._v(" variable with the wallet's first receive address.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("createOrRestoreWallet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),t._v(" mnemonic"),a("span",{pre:!0,attrs:{class:"token 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operator"}},[t._v("=")]),t._v(" res"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n displayText "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Wallet Created: ')]),a("span",{pre:!0,attrs:{class:"token interpolation"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("$")]),a("span",{pre:!0,attrs:{class:"token expression"}},[t._v("address")])]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token 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')]),a("span",{pre:!0,attrs:{class:"token interpolation"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("${")]),a("span",{pre:!0,attrs:{class:"token expression"}},[t._v("e"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("toString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),a("p",[t._v("A new button will be required to call "),a("code",[t._v("createOrRestoreWallet()")])]),t._v(" "),a("p",[t._v("Let's add a new button just below the mnemonic "),a("code",[t._v("TextFieldContainer")])]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("SubmitButton")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n text"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Create Wallet"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n callback"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("createOrRestoreWallet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n mnemonic"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("text"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" \n "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Network.Testnet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"password"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n")])])]),a("p",[t._v("The response returned by "),a("code",[t._v("create()")]),t._v(" is a "),a("code",[t._v("Wallet")]),t._v(" object.")]),t._v(" "),a("p",[t._v("The App should now be creating a wallet when we click "),a("strong",[t._v("Create Mnemonic")]),t._v(" followed by "),a("strong",[t._v("Create Wallet")]),t._v(".")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(342)}}),t._v(" "),a("p",[t._v("Before going forward, we need to create a "),a("code",[t._v("Blockchain")]),t._v(" object as well. The Blockchain object will encapsulate the bitcoin node configuration which the wallet will use for syncing blocks and broadcasting transactions.")]),t._v(" "),a("p",[t._v("Let's add an internal method to create and initialize the "),a("code",[t._v("Blockchain")]),t._v(" object.")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("blockchainInit")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n blockchain "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Blockchain")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("create")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n config"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BlockchainConfig")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("electrum")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n config"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ElectrumConfig")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n stopGap"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("10")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n timeout"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("5")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n retry"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("5")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n url"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"ssl://electrum.blockstream.info:60002"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n validateDomain"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("false")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),a("p",[t._v("Here we are initializing the "),a("code",[t._v("late")]),t._v(" non-nullable "),a("code",[t._v("blockchain")]),t._v(" variable, by calling the named constructor "),a("code",[t._v("create")]),t._v(", which takes a "),a("code",[t._v("BlockchainConfig")]),t._v(" object.\nThe bitcoin node specified is an Electrum node and we are specifying the url for Blockstream's public Electrum Testnet servers over SSL.")]),t._v(" "),a("p",[t._v("After creating the "),a("code",[t._v("blockchainInit()")]),t._v(" method, call it from "),a("code",[t._v("createOrRestoreWallet()")]),t._v(", so the "),a("code",[t._v("blockchain")]),t._v(" variable gets initialized before the "),a("code",[t._v("wallet")]),t._v(" is created.")]),t._v(" "),a("p",[t._v("Include the following line of code inside "),a("code",[t._v("createOrRestoreWallet()")]),t._v(" just before calling Wallet.create().")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("blockchainInit")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("final")]),t._v(" res "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Wallet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("create")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("\n")])])]),a("p",[a("strong",[t._v("blockChainConfig")]),t._v(": BlockchainConfig is an enum that has 3 values, "),a("code",[t._v("BlockchainConfig.electrum")]),t._v(" for "),a("a",{attrs:{href:"https://github.com/romanz/electrs",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("electrum")]),a("OutboundLink")],1),t._v(" ,"),a("code",[t._v("BlockchainConfig.esplora")]),t._v(" for "),a("a",{attrs:{href:"https://github.com/Blockstream/esplora",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("esplora")]),a("OutboundLink")],1),t._v(" and "),a("code",[t._v("BlockchainConfig.rpc")]),t._v(" .")]),t._v(" "),a("p",[a("code",[t._v("BlockchainConfig.electrum")]),t._v(", "),a("code",[t._v("BlockchainConfig.rpc")]),t._v(" & "),a("code",[t._v("BlockchainConfig.esplora")]),t._v(" has "),a("code",[t._v("ElectrumConfig")]),t._v(" object, "),a("code",[t._v("RpcConfig")]),t._v(" object and "),a("code",[t._v("EsploraConfig")]),t._v(" object, respectively as its parameter.")]),t._v(" "),a("p",[a("strong",[t._v("ElectrumConfig")]),t._v(": This is the object type of "),a("code",[t._v("BlockchainConfig.electrum")]),t._v("'s config that takes a timeout, retry & url as its required parameter.")]),t._v(" "),a("p",[a("strong",[t._v("EsploraConfig")]),t._v(": This is the object type of "),a("code",[t._v("BlockchainConfig.esplora")]),t._v("'s config that takes baseUrl & stopGap as its required parameter.")]),t._v(" "),a("p",[a("strong",[t._v("RpcConfig")]),t._v(": This is the object type of "),a("code",[t._v("BlockchainConfig.rpc")]),t._v("'s config that takes url, network, & walletName as its required parameter. If "),a("code",[t._v("Rpc Blockchain")]),t._v(" has its authentication values inside a cookie file, please pass in cookie path as authCookie parameter, or you can pass in rpc username and password using "),a("code",[t._v("UserPass")]),t._v(" class.")]),t._v(" "),a("p",[t._v("Refer to the readme for a complete list of options for "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter#createwallet",target:"_blank",rel:"noopener noreferrer"}},[t._v("createWallet()"),a("OutboundLink")],1)]),t._v(" "),a("h2",{attrs:{id:"utxos-and-balance"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#utxos-and-balance"}},[t._v("#")]),t._v(" UTXOs and balance")]),t._v(" "),a("p",[t._v("With the "),a("code",[t._v("Wallet")]),t._v(" and "),a("code",[t._v("Blockchain")]),t._v(" created, we can now add methods to sync UTXOs and compute balance.")]),t._v(" "),a("p",[a("code",[t._v("Wallet")]),t._v(" has a "),a("code",[t._v("sync")]),t._v(" method to sync all UTXOs belonging to the wallet using the "),a("code",[t._v("Blockchain")]),t._v(" object. Once the wallet sync is complete balance is computed and "),a("code",[t._v("getBalance")]),t._v(" can fetch the balance.")]),t._v(" "),a("p",[t._v("Earlier we have already added a variable for "),a("code",[t._v("balance")]),t._v(". Now we will add buttons to call "),a("code",[t._v("sync")]),t._v(" and "),a("code",[t._v("getBalance")]),t._v(". Just below the Create Wallet button let's add two buttons as follows:")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("SubmitButton")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v(" text"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string-literal"}},[a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Sync Wallet"')])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n callback"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token 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"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n wallet"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("sync")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("blockchain"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("We should now be able to create a wallet, sync UTXOs, and get the balance")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(343)}}),t._v(" "),a("p",[t._v("We can use a public testnet faucet to send testnet coins to the wallet and check that the UTXO sync and balance fetch are working correctly. Before we do that add one more method to generate a new address we can then use this address to get testnet coins from a faucet.")]),t._v(" "),a("p",[t._v("Let's use the "),a("code",[t._v("address")]),t._v(" variable that was created before for this, we need to add a button for "),a("strong",[t._v("Get Address")]),t._v(" and an internal function to call "),a("code",[t._v("Wallet")]),t._v(" and create a new address. Let's do the following")]),t._v(" "),a("p",[t._v("Add a new "),a("code",[t._v("getNewAddress")]),t._v(" function below the "),a("code",[t._v("syncWallet()")]),t._v(" function:")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Future")]),a("span",{pre:!0,attrs:{class:"token generics"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("getNewAddress")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n 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auto",zoom:"25%"},attrs:{src:s(344)}}),t._v(" "),a("p",[t._v("Now that we are able to generate a receive address we can get some testnet bitcoin from one of the public "),a("a",{attrs:{href:"https://coinfaucet.eu/en/btc-testnet/",target:"_blank",rel:"noopener noreferrer"}},[t._v("testnet faucets"),a("OutboundLink")],1)]),t._v(" "),a("p",[t._v("After we send and after the transaction is confirmed we will need to sync the wallet before we can see the new balance from the received transaction.")]),t._v(" "),a("h2",{attrs:{id:"restoring-a-wallet"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#restoring-a-wallet"}},[t._v("#")]),t._v(" Restoring a wallet")]),t._v(" "),a("p",[t._v("The "),a("code",[t._v("create")]),t._v(" method creates a wallet using a "),a("code",[t._v("mnemonic")]),t._v(", to restore we can use the same method, we won't need to call "),a("code",[t._v("generateMnemonic")]),t._v(" as we will already have a "),a("code",[t._v("mnemonic")]),t._v(" to restore with.")]),t._v(" "),a("p",[t._v("This text field below the "),a("code",[t._v("Generate Mnemonic")]),t._v(" button will also display the mnemonic variable if we click Generate Mnemonic' button. The generated mnemonic will show up in the text field. We can overwrite it with our mnemonic and doing so will also overwrite the mnemonic state variable. This way the mnemonic displayed will be the one used to create the wallet.")]),t._v(" "),a("p",[t._v("We can now use our mnemonic and use it to restore a wallet. This will come in handy if we have a wallet with testnet bitcoin as these are hard to come by.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"25%"},attrs:{src:s(345)}}),t._v(" "),a("h2",{attrs:{id:"sending-bitcoin"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#sending-bitcoin"}},[t._v("#")]),t._v(" Sending bitcoin")]),t._v(" "),a("p",[t._v("We are now able to receive bitcoin, now its time to add functionality to send a bitcoin transaction.")]),t._v(" "),a("p",[t._v("For making a successful bitcoin transaction "),a("code",[t._v("bdk-flutter")]),t._v(" utilizes a couple of methods. A new unsigned transaction can be created by using TxBuilder](https://github.com/LtbLightning/bdk-flutter#quicksend).")]),t._v(" "),a("p",[t._v("First, we have to initialize the "),a("code",[t._v("TxBuilder")]),t._v(" object and call the "),a("code",[t._v("addRecipient()")]),t._v(" method.\n"),a("code",[t._v("addRecipient()")]),t._v(" takes a "),a("code",[t._v("Script")]),t._v(" object and the transaction "),a("code",[t._v("amount")]),t._v(".")]),t._v(" "),a("div",{staticClass:"language-dart extra-class"},[a("pre",{pre:!0,attrs:{class:"language-dart"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("final")]),t._v(" res "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" txBuilder"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("addRecipient")]),a("span",{pre:!0,attrs:{class:"token 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The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by "),a("code",[t._v("bdk-flutter")]),t._v(" allowing us to focus on the product, functionality, and user journey. This is how "),a("code",[t._v("bdk")]),t._v(" and "),a("code",[t._v("bdk-flutter")]),t._v(" intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while "),a("code",[t._v("bdk")]),t._v(" handles bitcoin complexity.")]),t._v(" "),a("p",[a("code",[t._v("bdk-flutter")]),t._v(" intends to expose functionality and APIs from "),a("code",[t._v("bdk")]),t._v(" which has a wide variety of APIs with granular details allowing for many interesting use cases to be implemented. "),a("code",[t._v("bdk-flutter")]),t._v(" and "),a("code",[t._v("bdk")]),t._v(" are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.")]),t._v(" "),a("p",[t._v("Stay tuned for more APIs and enhancements coming to "),a("code",[t._v("bdk-flutter")]),t._v(" in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of "),a("code",[t._v("bdk-flutter")]),t._v(".")]),t._v(" "),a("p",[t._v("In the meantime keep in touch with the project by following us on "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter",target:"_blank",rel:"noopener noreferrer"}},[t._v("GitHub"),a("OutboundLink")],1),t._v(" and "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior",target:"_blank",rel:"noopener noreferrer"}},[t._v("Twitter"),a("OutboundLink")],1)]),t._v(" "),a("h4",{attrs:{id:"references"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#references"}},[t._v("#")]),t._v(" References:")]),t._v(" "),a("ul",[a("li",[a("a",{attrs:{href:"https://github.com/bitcoindevkit",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk-flutter"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-flutter-quickstart",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk-flutter-quickstart GitHub Repository"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://docs.flutter.dev/get-started/install",target:"_blank",rel:"noopener noreferrer"}},[t._v("Setup Flutter Development Environment"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("li",[t._v("Testnet Faucet: "),a("a",{attrs:{href:"https://coinfaucet.eu/en/btc-testnet/",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://coinfaucet.eu/en/btc-testnet/"),a("OutboundLink")],1),t._v(" or "),a("a",{attrs:{href:"https://bitcoinfaucet.uo1.net",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://bitcoinfaucet.uo1.net"),a("OutboundLink")],1)])])])}),[],!1,null,null,null);a.default=e.exports}}]); \ No newline at end of file diff --git a/assets/js/11.9cb88060.js b/assets/js/11.f7cf99f0.js similarity index 98% rename from assets/js/11.9cb88060.js rename to assets/js/11.f7cf99f0.js index daad319ca9..1a45096953 100644 --- a/assets/js/11.9cb88060.js +++ b/assets/js/11.f7cf99f0.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[11],{337:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_complete_app.e382f61c.png"},338:function(t,a,s){t.exports=s.p+"assets/img/default_rn_app.9e60b4fb.png"},339:function(t,a,s){t.exports=s.p+"assets/img/folder_structure.d1c95bd6.png"},340:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_title.289f266d.png"},341:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_tutorial_screen_mnemonic.9963c418.png"},342:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_tutorial_screen_createwallet.916f2610.png"},343:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_get_balance.75af17bf.png"},344:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_get_address.4f570fb2.png"},345:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_get_restore.134b3681.png"},346:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_send.4e9dbc4a.png"},406:function(t,a,s){"use strict";s.r(a);var n=s(7),e=Object(n.a)({},(function(){var t=this,a=t._self._c;return a("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[a("h2",{attrs:{id:"introduction"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#introduction"}},[t._v("#")]),t._v(" Introduction")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" is the "),a("strong",[t._v("Bitcoin Dev kit")]),t._v("'s "),a("strong",[t._v("React Native")]),t._v(" library which enables building bitcoin applications for Android and iOS mobile platforms. Using "),a("code",[t._v("bdk-rn")]),t._v(" does not require knowledge of the underlying bitcoin or BDK API. Using "),a("code",[t._v("bdk-rn")]),t._v(" is similar to using any other RN module. Just do "),a("code",[t._v("yarn add bdk-rn")]),t._v(" and you are ready to code! This is the first tutorial on how to use "),a("code",[t._v("bdk-rn")]),t._v(", more coming soon, make sure to "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior?ref_src=twsrc%5Etfw",target:"_blank",rel:"noopener noreferrer"}},[t._v("follow"),a("OutboundLink")],1),t._v(" to be notified of new ones. In case you missed it, there is a recorded "),a("code",[t._v("bdk-rn")]),t._v(" focused Twitch Livestream available on the "),a("a",{attrs:{href:"https://www.youtube.com/watch?v=gMpWA875go4",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Developers"),a("OutboundLink")],1),t._v(" YouTube channel which covers most of this article, make sure to subscribe to Bitcoin Developers "),a("a",{attrs:{href:"https://www.youtube.com/channel/UCUq_ZdezVWKPvkWRicAYxLA/videos",target:"_blank",rel:"noopener noreferrer"}},[t._v("YouTube Channel"),a("OutboundLink")],1),t._v(" for more bitcoin development videos.")]),t._v(" "),a("p",[t._v("In this tutorial, we will explore "),a("code",[t._v("bdk-rn")]),t._v(" usage and the API it provides. This guide will walk through the development process and code for making a bitcoin application. The bitcoin application we create will be a non-custodial HD Wallet. The application will have the functionality to create a new wallet or restore from a known mnemonic seed phrase. This application will also be able to interact with the bitcoin network to sync UTXOs from new blocks and broadcast transactions.")]),t._v(" "),a("p",[t._v("The tutorial will focus on bitcoin and "),a("code",[t._v("bdk-rn")]),t._v(" concepts and API. So it will gloss over React Native aspects. The code for this tutorial is available on the "),a("a",{attrs:{href:"https://github.com/LtbLightning/BdkRnQuickStart",target:"_blank",rel:"noopener noreferrer"}},[t._v("LtbLightning GitHub"),a("OutboundLink")],1)]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"50%"},attrs:{src:s(337),alt:"BDK RN Quick Start"}}),t._v(" "),a("h3",{attrs:{id:"prerequisites"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#prerequisites"}},[t._v("#")]),t._v(" Prerequisites")]),t._v(" "),a("p",[t._v("In order to use "),a("code",[t._v("bdk-rn")]),t._v(" in a React Native App, a React Native development environment is required. Please refer to resources out there on the internet if you need to set this up, here is one of many good resources to guide you on "),a("a",{attrs:{href:"https://reactnative.dev/docs/environment-setup",target:"_blank",rel:"noopener noreferrer"}},[t._v("environment setup"),a("OutboundLink")],1)]),t._v(" "),a("h3",{attrs:{id:"bitcoin-basics"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-basics"}},[t._v("#")]),t._v(" Bitcoin Basics")]),t._v(" "),a("p",[t._v("The bitcoin concepts used in this blog post are detailed and explained very well in external bitcoin resources. Here are some links for reference:")]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("p",[t._v("Now let's jump into Bitcoin Dev Kit")]),t._v(" "),a("h2",{attrs:{id:"bitcoin-dev-kit-and-bdk-rn"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-dev-kit-and-bdk-rn"}},[t._v("#")]),t._v(" Bitcoin Dev Kit and bdk-rn")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" is a React Native library of Bitcoin Dev Kit(BDK) for building React Native Apps.\nIt encapsulates all of the low-level APIs and methods for BDK and exposes them in a react native context. To use BDK in React Native(RN) apps only the "),a("code",[t._v("bdk-rn")]),t._v(" module is required. "),a("code",[t._v("Bdk-rn")]),t._v(" can be used like any other react native library and is available on "),a("a",{attrs:{href:"https://www.npmjs.com/package/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("public package managers(npm and yarn)"),a("OutboundLink")],1),t._v(".")]),t._v(" "),a("h2",{attrs:{id:"getting-started"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#getting-started"}},[t._v("#")]),t._v(" Getting Started")]),t._v(" "),a("p",[t._v("Although we won't delve deep into RN we will focus more on bitcoin and bdk-rn, however, some rudimentary RN setup is required, especially a basic RN app to add our code.")]),t._v(" "),a("p",[t._v("start by creating a new RN project.")]),t._v(" "),a("p",[a("code",[t._v("npx react-native init BdkRnQuickStart")])]),t._v(" "),a("p",[t._v("If this fails in an error on an M1/M2 Mac please use\n"),a("code",[t._v("arch -x86_64 pod install --repo-update")])]),t._v(" "),a("p",[t._v("Once done "),a("code",[t._v("cd")]),t._v(" into the new project directory and run the basic RN app that's created")]),t._v(" "),a("div",{staticClass:"language-shell extra-class"},[a("pre",{pre:!0,attrs:{class:"language-shell"}},[a("code",[a("span",{pre:!0,attrs:{class:"token builtin class-name"}},[t._v("cd")]),t._v(" BdkRnQuickStart\n"),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("yarn")]),t._v(" ios\n")])])]),a("p",[t._v("This should start building the app and launch the app in a simulator. 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To achieve this add the following code.")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// screens/home.js")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// add this as another state variable under mnemonic")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),t._v("displayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" setDisplayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("useState")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token 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We created a button click event handler to call bdk-rn. Set the display state variable to display the output of the call in the display section. We will follow this pattern for the remaining calls to bdk-rn.")]),t._v(" "),a("h2",{attrs:{id:"creating-a-wallet"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#creating-a-wallet"}},[t._v("#")]),t._v(" Creating a wallet")]),t._v(" "),a("p",[t._v("Before moving on to creating a wallet, let's add a section at the top to display the balance of the wallet.")]),t._v(" "),a("p",[t._v("To display the balance we will need a state variable to store the balance and a display section to display it.")]),t._v(" "),a("p",[t._v("Under the "),a("code",[t._v("mnemonic")]),t._v(" and "),a("code",[t._v("displayText")]),t._v(" variables, let's add one for "),a("code",[t._v("balance")]),t._v(" as well")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v("\t"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function-variable function"}},[t._v("Home")]),t._v(" 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function"}},[t._v("useState")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("Now we need some "),a("code",[t._v("jsx")]),t._v(" code to display the balance.")]),t._v(" "),a("p",[t._v("Just below "),a("code",[t._v("{/* Balance */}")]),t._v(" and above "),a("code",[t._v("{*/ method call result */}")]),t._v(" add the following UI components to display the balance. We only want to show the balance when it has a value so we will use a tertiary operator for a quick check.")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v("\t\t\t\t"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* Balance */")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\t\t\t\t"),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("View")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token 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function"}},[t._v("stringify")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("data"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("A new button will be required to trigger "),a("code",[t._v("createWallet")])]),t._v(" "),a("p",[t._v("Let's add a new button just above "),a("code",[t._v("{/* input boxes and send transaction button */}")])]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v("\t\t\t\t"),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token 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attr-name"}},[t._v("onPress")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("createWallet"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("/>")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* input boxes and send transaction button */")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),a("p",[t._v("The response returned by "),a("code",[t._v("createWallet")]),t._v(" is a new address for the created wallet.")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token string-property property"}},[t._v('"data"')]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token string-property property"}},[t._v('"address"')]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"tb1qxg8g8cdzgs09cttu3y7lc33udqc4wsesunjnhe"')]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token string-property property"}},[t._v('"error"')]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("false")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),a("p",[t._v("The App should now be creating a wallet when we click "),a("strong",[t._v("Create Mnemonic")]),t._v(" followed by "),a("strong",[t._v("Create Wallet")]),t._v(".")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"50%"},attrs:{src:s(342)}}),t._v(" "),a("p",[t._v("The wallet created is a HD wallet and the address displayed is the 0 index address for the wallet. The path used by default is 84'/1'/0'/0/* for addresses and 84'/1'/0'/1/* for change.")]),t._v(" "),a("p",[t._v("As we specified "),a("code",[t._v("testnet")]),t._v(" and did not specify "),a("code",[t._v("blockChainName")]),t._v(" and "),a("code",[t._v("blockChainConfigUrl")]),t._v(" a default testnet server will be used as the bitcoin node, "),a("code",[t._v("ssl://electrum.blockstream.info")]),t._v(" is the default url used for testnet.")]),t._v(" "),a("p",[t._v("Using "),a("code",[t._v("mnemonic")]),t._v(" is a quick way to create a new wallet with "),a("code",[t._v("bdk-rn")]),t._v(". The "),a("code",[t._v("createWallet()")]),t._v(" method in "),a("code",[t._v("bdk-rn")]),t._v(" has many optional arguments to configure the wallet. In addition to mnemonic, a wallet can also be created with a descriptor. If a descriptor is passed as an argument the wallet will be created using the descriptor. When using a descriptor, arguments for network, password and mnemonic are not required. "),a("code",[t._v("bdk-rn")]),t._v(" has a "),a("code",[t._v("createDescriptor()")]),t._v(" method to create a descriptor. More about output descriptors "),a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("here"),a("OutboundLink")],1),t._v(". Refer to the "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#createdescriptor",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),a("OutboundLink")],1),t._v(" for all options available when creating output descriptors with "),a("code",[t._v("bdk-rn")])]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// using a descriptor to create wallet ")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" response "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" BdkRn"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token literal-property property"}},[t._v("descriptor")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v("'tprv8ZgxMBicQKsPd3G66kPkZEuJZgUK9QXJRYCwnCtYLJjEZmw8xFjCxGoyx533AL83XFcSQeuVmVeJbZai5RTBxDp71Abd2FPSyQumRL79BKw'")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("Other arguments for "),a("code",[t._v("createWallet()")]),t._v(" are:")]),t._v(" "),a("p",[a("strong",[t._v("blockChainName")]),t._v(": Blockchain backend to use, like "),a("a",{attrs:{href:"https://github.com/romanz/electrs",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("electrum")]),a("OutboundLink")],1),t._v(", "),a("a",{attrs:{href:"https://github.com/Blockstream/esplora",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("esplora")]),a("OutboundLink")],1),t._v(", "),a("code",[t._v("compact-filters")]),t._v(" ("),a("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t._v("BIP157"),a("OutboundLink")],1),t._v(") and Bitcoin Core. "),a("code",[t._v("bdk-rn")]),t._v(" at the moment doesn't support compact-filters and Bitcoin Core, this will be added shortly in a future release.")]),t._v(" "),a("p",[a("strong",[t._v("blockChainConfigUrl")]),t._v(": This is the url of the specified bitcoin node this should match the chain and the type of blockchain specified as "),a("strong",[t._v("blockChainName")])]),t._v(" "),a("p",[t._v("Refer to "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#createwallet",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),a("OutboundLink")],1),t._v(" for a complete list of options for "),a("code",[t._v("createWallet")])]),t._v(" "),a("h2",{attrs:{id:"utxos-and-balance"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#utxos-and-balance"}},[t._v("#")]),t._v(" UTXOs and balance")]),t._v(" "),a("p",[t._v("With the wallet created, we can now add methods to sync UTXOs compute balance.")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" has a "),a("code",[t._v("syncWallet")]),t._v(" method to sync all UTXOs belonging to the wallet with the bitcoin network, the specified "),a("code",[t._v("blockChainName")]),t._v(" and "),a("code",[t._v("blockChainConfigUrl")]),t._v(" is used to sync. Once the wallet sync is complete balance is computed and "),a("code",[t._v("getBalance")]),t._v(" can fetch the balance.")]),t._v(" "),a("p",[t._v("Earlier we have aleady added state variables for"),a("code",[t._v("syncResponse")]),t._v("and "),a("code",[t._v("balance")]),t._v(". Now we will add buttons to call "),a("code",[t._v("syncWallet")]),t._v(" and "),a("code",[t._v("getBalance")]),t._v(". Just below the Create Wallet button lets add two buttons as follows:")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Button")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("title")]),a("span",{pre:!0,attrs:{class:"token attr-value"}},[a("span",{pre:!0,attrs:{class:"token punctuation attr-equals"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')]),t._v("Sync Wallet"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation 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"),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("title")]),a("span",{pre:!0,attrs:{class:"token attr-value"}},[a("span",{pre:!0,attrs:{class:"token punctuation attr-equals"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')]),t._v("Get Balance"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("styles"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("methodButton"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("onPress")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("getBalance"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("/>")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("")])]),t._v("\n")])])]),a("p",[t._v("And two click handlers below createWallet:")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function-variable function"}},[t._v("syncWallet")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" 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Before we do that add one more method to generate a new address we can then use this address to get testnet coins from a faucet.")]),t._v(" "),a("p",[t._v("Let's add a state variable for "),a("code",[t._v("address")]),t._v(", a button for "),a("strong",[t._v("Get Address")]),t._v(" and a click event handler to call "),a("code",[t._v("bdk-rn")]),t._v(" and create a new address. Let's do the following")]),t._v(" "),a("p",[t._v("Add "),a("code",[t._v("address")]),t._v(" and "),a("code",[t._v("setAddress")]),t._v(" state variables below balance and "),a("code",[t._v("setBalance")]),t._v(":")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),t._v("address"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" setAddress"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("useState")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token 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"),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("setDisplayText")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("data"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("And a Get Address button below the existing Get Balance button:")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Button")])]),t._v("\n\t"),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("title")]),a("span",{pre:!0,attrs:{class:"token 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punctuation"}},[t._v("{")]),t._v("getAddress"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("/>")])]),t._v("\n")])])]),a("p",[t._v("We should now have the following, and Get Address will be able to display a new address.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"50%"},attrs:{src:s(344)}}),t._v(" "),a("p",[t._v("Now that we are able to generate a receive address we can get some testnet bitcoin from one of the public "),a("a",{attrs:{href:"https://coinfaucet.eu/en/btc-testnet/",target:"_blank",rel:"noopener noreferrer"}},[t._v("testnet faucets"),a("OutboundLink")],1)]),t._v(" "),a("p",[t._v("After we send and after the transaction is confirmed we will need to sync the wallet before we can see the new balance from the received transaction.")]),t._v(" "),a("h2",{attrs:{id:"restoring-wallet"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#restoring-wallet"}},[t._v("#")]),t._v(" Restoring wallet")]),t._v(" "),a("p",[t._v("The "),a("code",[t._v("createWallet")]),t._v(" method creates a wallet using a "),a("code",[t._v("mnemonic")]),t._v(", in order to restore we can use the same method, we won't need to call "),a("code",[t._v("generateMnemonic")]),t._v(" as we will already have a "),a("code",[t._v("mnemonic")]),t._v(" to restore with.")]),t._v(" "),a("p",[t._v("Let's add an input box to enter our own "),a("code",[t._v("mnemonic")]),t._v(", we will use the "),a("code",[t._v("mnemonic")]),t._v(" entered in the input box to create a wallet.")]),t._v(" "),a("p",[t._v("Let's add an input box for "),a("code",[t._v("mnemonic")]),t._v(" below the Generate Mnemonic button.")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[a("span",{pre:!0,attrs:{class:"token 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display the mnemonic state variable in the input box, if we click Generate Mnemonic the generated mnemonic will show up in the input box. We can overwrite it with our own mnemonic and doing so will also overwrite the mnemonic state variable. This way the mnemonic displayed will be the one used to create the wallet.")]),t._v(" "),a("p",[t._v("we are already using the mnemonic state variable in the "),a("code",[t._v("createWallet")]),t._v(" Method so no other changes are required.")]),t._v(" "),a("p",[t._v("We can now use our own mnemonic and use it to restore a wallet. This will come in handy if we have a wallet with testnet bitcoin as these are hard to come by.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"50%"},attrs:{src:s(345)}}),t._v(" "),a("h2",{attrs:{id:"sending-bitcoin"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#sending-bitcoin"}},[t._v("#")]),t._v(" Sending bitcoin")]),t._v(" "),a("p",[t._v("We are now able to receive bitcoin, time to add functionality to send as well.")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" has a number of transaction-related methods to enable varied use cases. A new send transaction can be created and broadcast using "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#quicksend",target:"_blank",rel:"noopener noreferrer"}},[t._v("quickSend()"),a("OutboundLink")],1),t._v(". If required an unsigned transaction can be created using "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#createtransaction",target:"_blank",rel:"noopener noreferrer"}},[t._v("createTransaction()"),a("OutboundLink")],1),t._v(" , this can be signed later with "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#signtransaction",target:"_blank",rel:"noopener noreferrer"}},[t._v("signTransactioin()"),a("OutboundLink")],1),t._v(" method and broadcast using "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#broadcasttransaction",target:"_blank",rel:"noopener noreferrer"}},[t._v("broadcastTransaction()"),a("OutboundLink")],1),t._v(". There are also methods to query transactions by pending or confirmed status and all transactions. Please refer to "),a("code",[t._v("bdk-rn")]),t._v(" "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn/blob/main/README.md#gettransactions",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),a("OutboundLink")],1),t._v(" for more details on all the methods.")]),t._v(" "),a("p",[t._v("We will need state variables for recipient address and amount as well as for transaction, these can be added below our existing variables for syncResponse and address")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),t._v("syncResponse"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" setSyncResponse"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token 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We will need an input box for the receiver address and an input box for the amount to send. We will also need a button to trigger the transaction.")]),t._v(" "),a("p",[t._v("Let's add the send transaction section and UI components below "),a("code",[t._v("{/* input boxes and send transaction button */}")])]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* input boxes and send transaction button */")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("View")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token 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punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("/>")])]),a("span",{pre:!0,attrs:{class:"token plain-text"}},[t._v("\n ")]),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("")])]),a("span",{pre:!0,attrs:{class:"token plain-text"}},[t._v("\n ")]),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("")])]),t._v("\n")])])]),a("p",[t._v("We should now be able to send a transaction as long as there is sufficient balance.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"50%"},attrs:{src:s(346)}}),t._v(" "),a("h2",{attrs:{id:"conclusion"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#conclusion"}},[t._v("#")]),t._v(" Conclusion")]),t._v(" "),a("p",[t._v("The App we created can be built and distributed for both iOS and Android thus sharing a code base and reducing development time. The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by "),a("code",[t._v("bdk-rn")]),t._v(" allowing us to focus on the product, functionality and user journey. This is how "),a("code",[t._v("bdk")]),t._v(" and "),a("code",[t._v("bdk-rn")]),t._v(" intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while "),a("code",[t._v("bdk")]),t._v(" handles bitcoin complexity.")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" intends to expose functionality and APIs from "),a("code",[t._v("bdk")]),t._v(" which has a wide variety of API with granular details allowing for many interesting use cases to be implemented. "),a("code",[t._v("bdk-rn")]),t._v(" and "),a("code",[t._v("bdk")]),t._v(" are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.")]),t._v(" "),a("p",[t._v("Stay tuned for more APIs and enhancements coming to "),a("code",[t._v("bdk-rn")]),t._v(" in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of bdk-rn.")]),t._v(" "),a("p",[t._v("In the meantime keep in touch with the project by following on "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("GitHub"),a("OutboundLink")],1),t._v(" and "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior",target:"_blank",rel:"noopener noreferrer"}},[t._v("Twitter"),a("OutboundLink")],1)]),t._v(" "),a("h4",{attrs:{id:"references"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#references"}},[t._v("#")]),t._v(" References:")]),t._v(" "),a("ul",[a("li",[a("a",{attrs:{href:"https://github.com/bitcoindevkit",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk-rn"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://www.youtube.com/watch?v=gMpWA875go4",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Developers YouTube"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/BdkRnQuickStart",target:"_blank",rel:"noopener noreferrer"}},[t._v("BdkRnQuickStart App GitHub Repository"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://reactnative.dev/docs/environment-setup",target:"_blank",rel:"noopener noreferrer"}},[t._v("Setup React Native Development Environment"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("li",[t._v("Testnet Faucet: "),a("a",{attrs:{href:"https://coinfaucet.eu/en/btc-testnet/",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://coinfaucet.eu/en/btc-testnet/"),a("OutboundLink")],1),t._v(" or "),a("a",{attrs:{href:"https://bitcoinfaucet.uo1.net",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://bitcoinfaucet.uo1.net"),a("OutboundLink")],1)])])])}),[],!1,null,null,null);a.default=e.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[11],{326:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_complete_app.e382f61c.png"},327:function(t,a,s){t.exports=s.p+"assets/img/default_rn_app.9e60b4fb.png"},328:function(t,a,s){t.exports=s.p+"assets/img/folder_structure.d1c95bd6.png"},329:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_title.289f266d.png"},330:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_tutorial_screen_mnemonic.9963c418.png"},331:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_tutorial_screen_createwallet.916f2610.png"},332:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_get_balance.75af17bf.png"},333:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_get_address.4f570fb2.png"},334:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_get_restore.134b3681.png"},335:function(t,a,s){t.exports=s.p+"assets/img/bdk_rn_send.4e9dbc4a.png"},405:function(t,a,s){"use strict";s.r(a);var n=s(7),e=Object(n.a)({},(function(){var t=this,a=t._self._c;return a("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[a("h2",{attrs:{id:"introduction"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#introduction"}},[t._v("#")]),t._v(" Introduction")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" is the "),a("strong",[t._v("Bitcoin Dev kit")]),t._v("'s "),a("strong",[t._v("React Native")]),t._v(" library which enables building bitcoin applications for Android and iOS mobile platforms. Using "),a("code",[t._v("bdk-rn")]),t._v(" does not require knowledge of the underlying bitcoin or BDK API. Using "),a("code",[t._v("bdk-rn")]),t._v(" is similar to using any other RN module. Just do "),a("code",[t._v("yarn add bdk-rn")]),t._v(" and you are ready to code! This is the first tutorial on how to use "),a("code",[t._v("bdk-rn")]),t._v(", more coming soon, make sure to "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior?ref_src=twsrc%5Etfw",target:"_blank",rel:"noopener noreferrer"}},[t._v("follow"),a("OutboundLink")],1),t._v(" to be notified of new ones. In case you missed it, there is a recorded "),a("code",[t._v("bdk-rn")]),t._v(" focused Twitch Livestream available on the "),a("a",{attrs:{href:"https://www.youtube.com/watch?v=gMpWA875go4",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Developers"),a("OutboundLink")],1),t._v(" YouTube channel which covers most of this article, make sure to subscribe to Bitcoin Developers "),a("a",{attrs:{href:"https://www.youtube.com/channel/UCUq_ZdezVWKPvkWRicAYxLA/videos",target:"_blank",rel:"noopener noreferrer"}},[t._v("YouTube Channel"),a("OutboundLink")],1),t._v(" for more bitcoin development videos.")]),t._v(" "),a("p",[t._v("In this tutorial, we will explore "),a("code",[t._v("bdk-rn")]),t._v(" usage and the API it provides. This guide will walk through the development process and code for making a bitcoin application. The bitcoin application we create will be a non-custodial HD Wallet. The application will have the functionality to create a new wallet or restore from a known mnemonic seed phrase. This application will also be able to interact with the bitcoin network to sync UTXOs from new blocks and broadcast transactions.")]),t._v(" "),a("p",[t._v("The tutorial will focus on bitcoin and "),a("code",[t._v("bdk-rn")]),t._v(" concepts and API. So it will gloss over React Native aspects. The code for this tutorial is available on the "),a("a",{attrs:{href:"https://github.com/LtbLightning/BdkRnQuickStart",target:"_blank",rel:"noopener noreferrer"}},[t._v("LtbLightning GitHub"),a("OutboundLink")],1)]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"50%"},attrs:{src:s(326),alt:"BDK RN Quick Start"}}),t._v(" "),a("h3",{attrs:{id:"prerequisites"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#prerequisites"}},[t._v("#")]),t._v(" Prerequisites")]),t._v(" "),a("p",[t._v("In order to use "),a("code",[t._v("bdk-rn")]),t._v(" in a React Native App, a React Native development environment is required. Please refer to resources out there on the internet if you need to set this up, here is one of many good resources to guide you on "),a("a",{attrs:{href:"https://reactnative.dev/docs/environment-setup",target:"_blank",rel:"noopener noreferrer"}},[t._v("environment setup"),a("OutboundLink")],1)]),t._v(" "),a("h3",{attrs:{id:"bitcoin-basics"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-basics"}},[t._v("#")]),t._v(" Bitcoin Basics")]),t._v(" "),a("p",[t._v("The bitcoin concepts used in this blog post are detailed and explained very well in external bitcoin resources. Here are some links for reference:")]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("p",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("p",[t._v("Now let's jump into Bitcoin Dev Kit")]),t._v(" "),a("h2",{attrs:{id:"bitcoin-dev-kit-and-bdk-rn"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitcoin-dev-kit-and-bdk-rn"}},[t._v("#")]),t._v(" Bitcoin Dev Kit and bdk-rn")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" is a React Native library of Bitcoin Dev Kit(BDK) for building React Native Apps.\nIt encapsulates all of the low-level APIs and methods for BDK and exposes them in a react native context. To use BDK in React Native(RN) apps only the "),a("code",[t._v("bdk-rn")]),t._v(" module is required. "),a("code",[t._v("Bdk-rn")]),t._v(" can be used like any other react native library and is available on "),a("a",{attrs:{href:"https://www.npmjs.com/package/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("public package managers(npm and yarn)"),a("OutboundLink")],1),t._v(".")]),t._v(" "),a("h2",{attrs:{id:"getting-started"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#getting-started"}},[t._v("#")]),t._v(" Getting Started")]),t._v(" "),a("p",[t._v("Although we won't delve deep into RN we will focus more on bitcoin and bdk-rn, however, some rudimentary RN setup is required, especially a basic RN app to add our code.")]),t._v(" "),a("p",[t._v("start by creating a new RN project.")]),t._v(" "),a("p",[a("code",[t._v("npx react-native init BdkRnQuickStart")])]),t._v(" "),a("p",[t._v("If this fails in an error on an M1/M2 Mac please use\n"),a("code",[t._v("arch -x86_64 pod install --repo-update")])]),t._v(" "),a("p",[t._v("Once done "),a("code",[t._v("cd")]),t._v(" into the new project directory and run the basic RN app that's created")]),t._v(" "),a("div",{staticClass:"language-shell extra-class"},[a("pre",{pre:!0,attrs:{class:"language-shell"}},[a("code",[a("span",{pre:!0,attrs:{class:"token builtin class-name"}},[t._v("cd")]),t._v(" BdkRnQuickStart\n"),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("yarn")]),t._v(" ios\n")])])]),a("p",[t._v("This should start building the app and launch the app in a simulator. So far we have created a basic RN project if this doesn't work then refer to the React Native development setup guide to troubleshoot.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"25%"},attrs:{src:s(327)}}),t._v(" "),a("h2",{attrs:{id:"setting-up-styles-and-rn-app-structure"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#setting-up-styles-and-rn-app-structure"}},[t._v("#")]),t._v(" Setting up styles and RN app structure")]),t._v(" "),a("p",[t._v("Let's set up a very basic app structure and some RN scaffolding. Let's create an "),a("code",[t._v("src")]),t._v(" folder in the project root and inside it add new folders for "),a("code",[t._v("assets")]),t._v(", "),a("code",[t._v("elements")]),t._v(", "),a("code",[t._v("screens")]),t._v(" and "),a("code",[t._v("styles")])]),t._v(" "),a("p",[t._v("To make this quick you can download the styles and images used in the tutorial from the repository. The image assets, "),a("code",[t._v("Button.tsx")]),t._v(" and "),a("code",[t._v("styles.js")]),t._v(" can be taken from "),a("a",{attrs:{href:"https://github.com/LtbLightning/BdkRnQuickStart/tree/master/src",target:"_blank",rel:"noopener noreferrer"}},[t._v("here"),a("OutboundLink")],1),t._v(" and moved to the folders as shown. Alternatively, you can write your own styles and use your own images if you intend to style the app in a different way.")]),t._v(" "),a("p",[t._v("Create a "),a("code",[t._v("home.js")]),t._v(" file under "),a("code",[t._v("screens")]),t._v(" folder, this will be where we will be adding most of the code.")]),t._v(" "),a("p",[t._v("Once done the project structure should look like this:")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"67%"},attrs:{src:s(328)}}),t._v(" "),a("p",[t._v("Locate "),a("code",[t._v("App.js")]),t._v(" in the project root, this will have the default code added by "),a("code",[t._v("react-native init")]),t._v(", let's delete all contents of "),a("code",[t._v("App.js")]),t._v(" and replace it with code to import "),a("code",[t._v("home.js")]),t._v(" as our main screen.")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[a("span",{pre:!0,attrs:{class:"token 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fine, it will be fixed in the next step.")]),t._v(" "),a("h2",{attrs:{id:"installing-bdk-rn"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#installing-bdk-rn"}},[t._v("#")]),t._v(" Installing "),a("code",[t._v("bdk-rn")])]),t._v(" "),a("p",[t._v("With the RN app project in place, we can now add "),a("code",[t._v("bdk-rn")]),t._v(" using either npm or yarn.")]),t._v(" "),a("p",[t._v("Using npm:")]),t._v(" "),a("div",{staticClass:"language-shell extra-class"},[a("pre",{pre:!0,attrs:{class:"language-shell"}},[a("code",[a("span",{pre:!0,attrs:{class:"token function"}},[t._v("npm")]),t._v(" i "),a("span",{pre:!0,attrs:{class:"token parameter variable"}},[t._v("--save")]),t._v(" bdk-rn\n")])])]),a("p",[t._v("Using yarn:")]),t._v(" "),a("div",{staticClass:"language-shell extra-class"},[a("pre",{pre:!0,attrs:{class:"language-shell"}},[a("code",[a("span",{pre:!0,attrs:{class:"token function"}},[t._v("yarn")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("add")]),t._v(" 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We will also need a button which will invoke generateMnemonic when clicked. 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To achieve this add the following code.")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// screens/home.js")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// add this as another state variable under mnemonic")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),t._v("displayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" setDisplayText"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("useState")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token 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*/}")])]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// screens/home.js")]),t._v("\n\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* method call result */")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\t"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// display the component only if displayText has a value")]),t._v("\n\t"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("displayText "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&&")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token 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We created a button click event handler to call bdk-rn. Set the display state variable to display the output of the call in the display section. We will follow this pattern for the remaining calls to bdk-rn.")]),t._v(" "),a("h2",{attrs:{id:"creating-a-wallet"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#creating-a-wallet"}},[t._v("#")]),t._v(" Creating a wallet")]),t._v(" "),a("p",[t._v("Before moving on to creating a wallet, let's add a section at the top to display the balance of the wallet.")]),t._v(" "),a("p",[t._v("To display the balance we will need a state variable to store the balance and a display section to display it.")]),t._v(" "),a("p",[t._v("Under the "),a("code",[t._v("mnemonic")]),t._v(" and "),a("code",[t._v("displayText")]),t._v(" variables, let's add one for "),a("code",[t._v("balance")]),t._v(" as well")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v("\t"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function-variable function"}},[t._v("Home")]),t._v(" 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We only want to show the balance when it has a value so we will use a tertiary operator for a quick check.")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v("\t\t\t\t"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* Balance */")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\t\t\t\t"),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("View")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token 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"),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("false")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),a("p",[t._v("The App should now be creating a wallet when we click "),a("strong",[t._v("Create Mnemonic")]),t._v(" followed by "),a("strong",[t._v("Create Wallet")]),t._v(".")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"50%"},attrs:{src:s(331)}}),t._v(" "),a("p",[t._v("The wallet created is a HD wallet and the address displayed is the 0 index address for the wallet. The path used by default is 84'/1'/0'/0/* for addresses and 84'/1'/0'/1/* for change.")]),t._v(" "),a("p",[t._v("As we specified "),a("code",[t._v("testnet")]),t._v(" and did not specify "),a("code",[t._v("blockChainName")]),t._v(" and "),a("code",[t._v("blockChainConfigUrl")]),t._v(" a default testnet server will be used as the bitcoin node, "),a("code",[t._v("ssl://electrum.blockstream.info")]),t._v(" is the default url used for testnet.")]),t._v(" "),a("p",[t._v("Using "),a("code",[t._v("mnemonic")]),t._v(" is a quick way to create a new wallet with "),a("code",[t._v("bdk-rn")]),t._v(". The "),a("code",[t._v("createWallet()")]),t._v(" method in "),a("code",[t._v("bdk-rn")]),t._v(" has many optional arguments to configure the wallet. In addition to mnemonic, a wallet can also be created with a descriptor. If a descriptor is passed as an argument the wallet will be created using the descriptor. When using a descriptor, arguments for network, password and mnemonic are not required. "),a("code",[t._v("bdk-rn")]),t._v(" has a "),a("code",[t._v("createDescriptor()")]),t._v(" method to create a descriptor. More about output descriptors "),a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("here"),a("OutboundLink")],1),t._v(". Refer to the "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#createdescriptor",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),a("OutboundLink")],1),t._v(" for all options available when creating output descriptors with "),a("code",[t._v("bdk-rn")])]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// using a descriptor to create wallet ")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" response "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" BdkRn"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token literal-property property"}},[t._v("descriptor")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v("'tprv8ZgxMBicQKsPd3G66kPkZEuJZgUK9QXJRYCwnCtYLJjEZmw8xFjCxGoyx533AL83XFcSQeuVmVeJbZai5RTBxDp71Abd2FPSyQumRL79BKw'")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("Other arguments for "),a("code",[t._v("createWallet()")]),t._v(" are:")]),t._v(" "),a("p",[a("strong",[t._v("blockChainName")]),t._v(": Blockchain backend to use, like "),a("a",{attrs:{href:"https://github.com/romanz/electrs",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("electrum")]),a("OutboundLink")],1),t._v(", "),a("a",{attrs:{href:"https://github.com/Blockstream/esplora",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("esplora")]),a("OutboundLink")],1),t._v(", "),a("code",[t._v("compact-filters")]),t._v(" ("),a("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t._v("BIP157"),a("OutboundLink")],1),t._v(") and Bitcoin Core. "),a("code",[t._v("bdk-rn")]),t._v(" at the moment doesn't support compact-filters and Bitcoin Core, this will be added shortly in a future release.")]),t._v(" "),a("p",[a("strong",[t._v("blockChainConfigUrl")]),t._v(": This is the url of the specified bitcoin node this should match the chain and the type of blockchain specified as "),a("strong",[t._v("blockChainName")])]),t._v(" "),a("p",[t._v("Refer to "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#createwallet",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),a("OutboundLink")],1),t._v(" for a complete list of options for "),a("code",[t._v("createWallet")])]),t._v(" "),a("h2",{attrs:{id:"utxos-and-balance"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#utxos-and-balance"}},[t._v("#")]),t._v(" UTXOs and balance")]),t._v(" "),a("p",[t._v("With the wallet created, we can now add methods to sync UTXOs compute balance.")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" has a "),a("code",[t._v("syncWallet")]),t._v(" method to sync all UTXOs belonging to the wallet with the bitcoin network, the specified "),a("code",[t._v("blockChainName")]),t._v(" and "),a("code",[t._v("blockChainConfigUrl")]),t._v(" is used to sync. Once the wallet sync is complete balance is computed and "),a("code",[t._v("getBalance")]),t._v(" can fetch the balance.")]),t._v(" "),a("p",[t._v("Earlier we have aleady added state variables for"),a("code",[t._v("syncResponse")]),t._v("and "),a("code",[t._v("balance")]),t._v(". Now we will add buttons to call "),a("code",[t._v("syncWallet")]),t._v(" and "),a("code",[t._v("getBalance")]),t._v(". Just below the Create Wallet button lets add two buttons as follows:")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Button")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("title")]),a("span",{pre:!0,attrs:{class:"token attr-value"}},[a("span",{pre:!0,attrs:{class:"token punctuation attr-equals"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')]),t._v("Sync Wallet"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation 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"),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("title")]),a("span",{pre:!0,attrs:{class:"token attr-value"}},[a("span",{pre:!0,attrs:{class:"token punctuation attr-equals"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')]),t._v("Get Balance"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("styles"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("methodButton"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("onPress")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("getBalance"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("/>")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("")])]),t._v("\n")])])]),a("p",[t._v("And two click handlers below createWallet:")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[t._v("\n "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function-variable function"}},[t._v("syncWallet")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("async")]),t._v(" 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punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("We should now be able to create a wallet, sync UTXOs and get balance")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"50%"},attrs:{src:s(332)}}),t._v(" "),a("p",[t._v("We can use a public testnet faucet to send testnet coins to the wallet and check that the UTXO sync and balance fetch are working correctly. Before we do that add one more method to generate a new address we can then use this address to get testnet coins from a faucet.")]),t._v(" "),a("p",[t._v("Let's add a state variable for "),a("code",[t._v("address")]),t._v(", a button for "),a("strong",[t._v("Get Address")]),t._v(" and a click event handler to call "),a("code",[t._v("bdk-rn")]),t._v(" and create a new address. Let's do the following")]),t._v(" "),a("p",[t._v("Add "),a("code",[t._v("address")]),t._v(" and "),a("code",[t._v("setAddress")]),t._v(" state variables below balance and "),a("code",[t._v("setBalance")]),t._v(":")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),t._v("address"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" setAddress"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("useState")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token 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"),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("setDisplayText")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("data"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])])]),a("p",[t._v("And a Get Address button below the existing Get Balance button:")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Button")])]),t._v("\n\t"),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("title")]),a("span",{pre:!0,attrs:{class:"token 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"),a("h2",{attrs:{id:"restoring-wallet"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#restoring-wallet"}},[t._v("#")]),t._v(" Restoring wallet")]),t._v(" "),a("p",[t._v("The "),a("code",[t._v("createWallet")]),t._v(" method creates a wallet using a "),a("code",[t._v("mnemonic")]),t._v(", in order to restore we can use the same method, we won't need to call "),a("code",[t._v("generateMnemonic")]),t._v(" as we will already have a "),a("code",[t._v("mnemonic")]),t._v(" to restore with.")]),t._v(" "),a("p",[t._v("Let's add an input box to enter our own "),a("code",[t._v("mnemonic")]),t._v(", we will use the "),a("code",[t._v("mnemonic")]),t._v(" entered in the input box to create a wallet.")]),t._v(" "),a("p",[t._v("Let's add an input box for "),a("code",[t._v("mnemonic")]),t._v(" below the Generate Mnemonic button.")]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[a("span",{pre:!0,attrs:{class:"token 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display the mnemonic state variable in the input box, if we click Generate Mnemonic the generated mnemonic will show up in the input box. We can overwrite it with our own mnemonic and doing so will also overwrite the mnemonic state variable. This way the mnemonic displayed will be the one used to create the wallet.")]),t._v(" "),a("p",[t._v("we are already using the mnemonic state variable in the "),a("code",[t._v("createWallet")]),t._v(" Method so no other changes are required.")]),t._v(" "),a("p",[t._v("We can now use our own mnemonic and use it to restore a wallet. This will come in handy if we have a wallet with testnet bitcoin as these are hard to come by.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"50%"},attrs:{src:s(334)}}),t._v(" "),a("h2",{attrs:{id:"sending-bitcoin"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#sending-bitcoin"}},[t._v("#")]),t._v(" Sending bitcoin")]),t._v(" "),a("p",[t._v("We are now able to receive bitcoin, time to add functionality to send as well.")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" has a number of transaction-related methods to enable varied use cases. A new send transaction can be created and broadcast using "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#quicksend",target:"_blank",rel:"noopener noreferrer"}},[t._v("quickSend()"),a("OutboundLink")],1),t._v(". If required an unsigned transaction can be created using "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#createtransaction",target:"_blank",rel:"noopener noreferrer"}},[t._v("createTransaction()"),a("OutboundLink")],1),t._v(" , this can be signed later with "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#signtransaction",target:"_blank",rel:"noopener noreferrer"}},[t._v("signTransactioin()"),a("OutboundLink")],1),t._v(" method and broadcast using "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#broadcasttransaction",target:"_blank",rel:"noopener noreferrer"}},[t._v("broadcastTransaction()"),a("OutboundLink")],1),t._v(". There are also methods to query transactions by pending or confirmed status and all transactions. Please refer to "),a("code",[t._v("bdk-rn")]),t._v(" "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn/blob/main/README.md#gettransactions",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),a("OutboundLink")],1),t._v(" for more details on all the methods.")]),t._v(" "),a("p",[t._v("We will need state variables for recipient address and amount as well as for transaction, these can be added below our existing variables for syncResponse and address")]),t._v(" "),a("div",{staticClass:"language-javascript extra-class"},[a("pre",{pre:!0,attrs:{class:"language-javascript"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),t._v("syncResponse"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" setSyncResponse"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token 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We will need an input box for the receiver address and an input box for the amount to send. We will also need a button to trigger the transaction.")]),t._v(" "),a("p",[t._v("Let's add the send transaction section and UI components below "),a("code",[t._v("{/* input boxes and send transaction button */}")])]),t._v(" "),a("div",{staticClass:"language-jsx extra-class"},[a("pre",{pre:!0,attrs:{class:"language-jsx"}},[a("code",[t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/* input boxes and send transaction button */")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("View")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token 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attr-equals"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')]),t._v("Send Transaction"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v('"')])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("style")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("styles"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("methodButton"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token attr-name"}},[t._v("onPress")]),a("span",{pre:!0,attrs:{class:"token script language-javascript"}},[a("span",{pre:!0,attrs:{class:"token script-punctuation punctuation"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("sendTx"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")])]),t._v("\n "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("/>")])]),a("span",{pre:!0,attrs:{class:"token plain-text"}},[t._v("\n ")]),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("")])]),a("span",{pre:!0,attrs:{class:"token plain-text"}},[t._v("\n ")]),a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token tag"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("")])]),t._v("\n")])])]),a("p",[t._v("We should now be able to send a transaction as long as there is sufficient balance.")]),t._v(" "),a("img",{staticStyle:{display:"block",margin:"0px auto",zoom:"50%"},attrs:{src:s(335)}}),t._v(" "),a("h2",{attrs:{id:"conclusion"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#conclusion"}},[t._v("#")]),t._v(" Conclusion")]),t._v(" "),a("p",[t._v("The App we created can be built and distributed for both iOS and Android thus sharing a code base and reducing development time. The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by "),a("code",[t._v("bdk-rn")]),t._v(" allowing us to focus on the product, functionality and user journey. This is how "),a("code",[t._v("bdk")]),t._v(" and "),a("code",[t._v("bdk-rn")]),t._v(" intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while "),a("code",[t._v("bdk")]),t._v(" handles bitcoin complexity.")]),t._v(" "),a("p",[a("code",[t._v("bdk-rn")]),t._v(" intends to expose functionality and APIs from "),a("code",[t._v("bdk")]),t._v(" which has a wide variety of API with granular details allowing for many interesting use cases to be implemented. "),a("code",[t._v("bdk-rn")]),t._v(" and "),a("code",[t._v("bdk")]),t._v(" are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.")]),t._v(" "),a("p",[t._v("Stay tuned for more APIs and enhancements coming to "),a("code",[t._v("bdk-rn")]),t._v(" in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of bdk-rn.")]),t._v(" "),a("p",[t._v("In the meantime keep in touch with the project by following on "),a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("GitHub"),a("OutboundLink")],1),t._v(" and "),a("a",{attrs:{href:"https://twitter.com/BitcoinZavior",target:"_blank",rel:"noopener noreferrer"}},[t._v("Twitter"),a("OutboundLink")],1)]),t._v(" "),a("h4",{attrs:{id:"references"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#references"}},[t._v("#")]),t._v(" References:")]),t._v(" "),a("ul",[a("li",[a("a",{attrs:{href:"https://github.com/bitcoindevkit",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("bdk-rn"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://www.youtube.com/watch?v=gMpWA875go4",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Developers YouTube"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/LtbLightning/BdkRnQuickStart",target:"_blank",rel:"noopener noreferrer"}},[t._v("BdkRnQuickStart App GitHub Repository"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://reactnative.dev/docs/environment-setup",target:"_blank",rel:"noopener noreferrer"}},[t._v("Setup React Native Development Environment"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc",target:"_blank",rel:"noopener noreferrer"}},[t._v("Mastering Bitcoin(HD Wallet chapter)"),a("OutboundLink")],1)]),t._v(" "),a("li",[a("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md",target:"_blank",rel:"noopener noreferrer"}},[t._v("Bitcoin Output Descriptors from bitcoin GitHub"),a("OutboundLink")],1)]),t._v(" "),a("li",[t._v("Testnet Faucet: "),a("a",{attrs:{href:"https://coinfaucet.eu/en/btc-testnet/",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://coinfaucet.eu/en/btc-testnet/"),a("OutboundLink")],1),t._v(" or "),a("a",{attrs:{href:"https://bitcoinfaucet.uo1.net",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://bitcoinfaucet.uo1.net"),a("OutboundLink")],1)])])])}),[],!1,null,null,null);a.default=e.exports}}]); \ No newline at end of file diff --git a/assets/js/12.988cda34.js b/assets/js/12.68344016.js similarity index 98% rename from assets/js/12.988cda34.js rename to assets/js/12.68344016.js index 04ebdea0ec..9c2306b6df 100644 --- a/assets/js/12.988cda34.js +++ b/assets/js/12.68344016.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[12],{321:function(t,e,a){t.exports=a.p+"assets/img/BDK-RN-Architecture.42fbc351.png"},322:function(t,e,a){t.exports=a.p+"assets/img/BDK-RN.370f20c3.png"},323:function(t,e,a){t.exports=a.p+"assets/img/android_folder.0ff999be.png"},365:function(t,e,a){"use strict";a.r(e);var n=a(7),s=Object(n.a)({},(function(){var t=this,e=t._self._c;return e("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[e("p",[t._v("The "),e("strong",[t._v("BitcoinDevkit")]),t._v("'s "),e("strong",[t._v("React Native")]),t._v(" library ("),e("code",[t._v("bdk-rn")]),t._v(") makes it easy to develop bitcoin applications for both Android and iOS mobile platforms. Using "),e("code",[t._v("bdk-rn")]),t._v(", knowledge of the underlying bitcoin and BDK API is not required and using "),e("code",[t._v("bdk-rn")]),t._v(" is similar to using any other RN module. The goal is "),e("strong",[t._v("Rapid Bitcoin Application Development")]),t._v(" by doing the heavy lifting in advance and providing a reusable library for other developers to use. Developers simply install using "),e("code",[t._v("yarn add")]),t._v(" and start using it in a React Native Project. The native code, Rust lang implementation, configuration and other setup details are all taken care of by "),e("code",[t._v("bdk-rn")]),t._v(".")]),t._v(" "),e("p",[t._v("This article is "),e("strong",[t._v("NOT a guide on how to use bdk-rn")]),t._v(" to build a bitcoin application, rather this is an insight into how "),e("code",[t._v("bdk-rn")]),t._v(" was developed. For help on how to use "),e("code",[t._v("bdk-rn")]),t._v(" to develop a bitcoin wallet or application please refer to the user guide in the "),e("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#usage",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),e("OutboundLink")],1),t._v(" on Github. There will be "),e("code",[t._v("how to guides")]),t._v(" published shortly on getting started with "),e("code",[t._v("bdk-rn")]),t._v(".")]),t._v(" "),e("h2",{attrs:{id:"react-native-architecture"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#react-native-architecture"}},[t._v("#")]),t._v(" React Native Architecture")]),t._v(" "),e("p",[t._v("At a high level, RN consists of the UI front which is essentially JavaScript which interacts with the native iOS and Android platforms over a bridge. When communicating over the bridge values from JS are converted to native and vice versa.")]),t._v(" "),e("p",[t._v("The native part of RN consists of Android as well as iOS modules and components. The Android and iOS sections are full fledged native projects which interact with the JS side over the native bridge. A RN project has all the build configuraiton required to build both Android and iOS projects.")]),t._v(" "),e("p",[t._v("For the purpose of making "),e("code",[t._v("bdk-rn")]),t._v(", "),e("code",[t._v("bdk-kotlin")]),t._v(" is used as the native Android module and "),e("code",[t._v("bdk-swift")]),t._v(" as the native iOS module. These are configured and wrapped in a RN Project as part of the platform specific native modules within the RN Project. This RN Project is then built to be a reusable React Native module.")]),t._v(" "),e("figure",[e("img",{attrs:{src:a(321),alt:""}})]),t._v(" "),e("h2",{attrs:{id:"native-integration"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#native-integration"}},[t._v("#")]),t._v(" Native Integration")]),t._v(" "),e("p",[t._v("In order to communicate to native modules on Android and iOS, React Native provides React Context API for Java/Kotlin as well as Swift. React Context API are used to build the interface to the native bridge allowing communication from JS to native modules.")]),t._v(" "),e("p",[t._v("bdk-rn uses React Context API plus some native code to wrap and enhance bdk-kotlin and bdk-swift APIs. The native code calls and interacts with the Android and iOS native modules which interface with the underlying mobile platform.")]),t._v(" "),e("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"20%"},attrs:{src:a(322)}}),t._v(" "),e("h2",{attrs:{id:"android-module"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#android-module"}},[t._v("#")]),t._v(" Android Module")]),t._v(" "),e("p",[t._v("We will go into the details of how the BDK Android Module is integrated, we wont cover iOS.")]),t._v(" "),e("p",[t._v("Starting off with a basic RN project. This project will be enhanced with bdk-kotlin and bdk-swift binaries and native code. For now lets go into the details for Android, iOS has similar steps to be done in Swift.")]),t._v(" "),e("p",[t._v("The Android native project is located under the root project folder.")]),t._v(" "),e("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"120%"},attrs:{src:a(323)}}),t._v(" "),e("p",[t._v("Here we need to add a dependency in "),e("code",[t._v("build.gradle")]),t._v(" for bdk-kotlin's android native binary. This will enable bdk-kotlin to be downloaded and available as one of the native modules.")]),t._v(" "),e("div",{staticClass:"language-javascript extra-class"},[e("pre",{pre:!0,attrs:{class:"language-javascript"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: build.gradle")]),t._v("\n\nrepositories "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("mavenCentral")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\ndependencies "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//noinspection GradleDynamicVersion")]),t._v("\n implementation "),e("span",{pre:!0,attrs:{class:"token string"}},[t._v("'com.facebook.react:react-native:+'")]),t._v("\n\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// bitcoindevkit")]),t._v("\n implementation "),e("span",{pre:!0,attrs:{class:"token string"}},[t._v("'org.bitcoindevkit:bdk-android:0.7.1'")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("We will create an Android native module which will interact with "),e("code",[t._v("bdk-android")]),t._v(".\nThis is done by adding a new Kotlin file "),e("code",[t._v("BdkRnModule.kt")]),t._v(" inside "),e("code",[t._v("android/app/src/main/java/com/bdkrn/")]),t._v(" folder")]),t._v(" "),e("p",[t._v("This will be part of the native code for bdk-rn module.Here a new class will be created to encapsulate the interaction with bitcoindevkit's android native binary.")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" android"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("annotation"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("SuppressLint\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" android"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("util"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Log\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Arguments\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Promise "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("as")]),t._v(" Result\n")])])]),e("p",[e("code",[t._v("org.bitcoindevkit")]),t._v(" will also need to be imported here")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" org"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bitcoindevkit"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Wallet "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("as")]),t._v(" BdkWallet\n")])])]),e("p",[t._v("To use React Context API "),e("code",[t._v("com.facebook.react.bridge.*")]),t._v(" also needs to be imported")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),t._v("\n")])])]),e("p",[t._v("A new class needs to be defined here which will implement the React Context API")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("BdkRnModule")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("reactContext"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" ReactApplicationContext"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v("\n\t"),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("ReactContextBaseJavaModule")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("reactContext"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("override")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fun")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getName")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('"BdkRnModule"')])]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("With the base imports and class defined, we can start writing methods.\nThis will demonstrate how bdk native module will be called and how values will be returned to JS over the native bridge")]),t._v(" "),e("p",[t._v("Lets create a method that can be called from JaveScript, to do so we use the "),e("code",[t._v("@ReactMethod")]),t._v(" directive which is part of the React Context API. This will expose the method so that it can be called from JavaScript.")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token annotation builtin"}},[t._v("@ReactMethod")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fun")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" Promise"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n \n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("We need one more file to complete our native framework. A new Kotlin file, "),e("code",[t._v("BdkRnPackage.kt")]),t._v(" is required to package all our native code into a new android module, here we specify the name of the file we just crated as the module name("),e("code",[t._v("BdkRnModule")]),t._v("). This can be done by adding the following code:")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnPackage.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("ReactPackage\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("NativeModule\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("ReactApplicationContext\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("uimanager"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("ViewManager\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" BdkRnPackage "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" ReactPackage "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("override")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fun")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("createNativeModules")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("reactContext"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" ReactApplicationContext"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v("\n MutableList"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),t._v("NativeModule"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("mutableListOf")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("BdkRnModule")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("reactContext"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),e("p",[t._v("Now lets add code for creating a wallet in BdkRnModule.kt")]),t._v(" "),e("p",[t._v("The methods used here are for bdk-kotlin and available in the bdk-kotlin documentation.")]),t._v(" "),e("p",[t._v("We first create a key info object")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token annotation builtin"}},[t._v("@ReactMethod")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fun")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" Promise"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Create key info with a new mnemonic")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" keys"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" ExtendedKeyInfo "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("generateExtendedKey")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n Network"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("TESTNET"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n WordCount"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("WORDS12"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('""')])]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n \n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// more code to follow...")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create descriptor and change descriptor")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create databaseConfig and blockchainconfig")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create wallet")]),t._v("\n \n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("Then key info used to create a wallet descriptor and change descriptor:")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" descriptor"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" String "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('"wpkh("')])]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" keys"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("xprv "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(' "'),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("84")]),t._v("'"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v("'"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),t._v("'"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/*)\"\n\nval changeDescriptor: String = descriptor.replace(\"/84'/1'/0'/0/*\",\"/84'/1'/0'/1/*\")\n")])])])]),e("p",[t._v("To create a wallet with bdk we need to specify wallet descriptor, network, a database config, blockchain config. We intend to use bitcoin testnet and want to use default memory for data. For bitcoin node we will use a public electrum server. We will need to define these parameters to create a wallet.")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" network "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" `Network"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("TESTNET`\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" databaseConfig "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" DatabaseConfig"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Memory\nblockchainConfig "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v("\n BlockchainConfig"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("Electrum")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("ElectrumConfig")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('"ssl://electrum.blockstream.info:60002"')])]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("null")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" 5u"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("null")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" 10u"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("Once done we can use these parameters to create a BDK wallet using the native android BDK library:")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")]),t._v(" wallet"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" BdkWallet "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("BdkWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n descriptor"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n changeDescriptor"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("setNetwork")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("network"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n databaseConfig"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n config\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("Once we have a wallet initialised, we can call methods on it to sync, generate a new address and to get balance")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[t._v("wallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("sync")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("ProgressLog"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" maxAddress"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n\nwallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getNewAddress")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n\nwallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getBalance")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("toLong")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("To return a value from the native android code to React Native’s Javascript side over the JS Native bridge we will use "),e("code",[t._v("com.facebook.react.bridge.Promise")]),t._v(". To return balance information to JS, the following code can be used")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" balance"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" String "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" wallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getBalance")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("toLong")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\nresult"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("resolve")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("balance"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("At this point we have an Android native module and it can be invoked from JS by calling "),e("code",[t._v("createWallet")]),t._v(" and it will return the balance.")]),t._v(" "),e("p",[t._v("This project can be imported into any RN project to reuse the defined "),e("code",[t._v("createWallet")]),t._v(" method without the need to carry out the setup described above.")]),t._v(" "),e("div",{staticClass:"language-javascript extra-class"},[e("pre",{pre:!0,attrs:{class:"language-javascript"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// any js file in React Native")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" BdkRn "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("from")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token string"}},[t._v("'bdk-rn'")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create a wallet and retrieve current balance")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" balance "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" BdkRn"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nconsole"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("log")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v(" balance "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n\n")])])]),e("p",[t._v("The actual "),e("code",[t._v("bdk-rn")]),t._v(" module has organised the native code into granular methods for different stages of creating a wallet and for different interactions and use cases for a bitcoin application, like generating, mnemonic, keys, creating wallet for different networks, creating descriptors, creating or restoring wallet, fetching balance, fetching transactions and many other methods. Please refer to the "),e("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#usage",target:"_blank",rel:"noopener noreferrer"}},[t._v("user guide in the readme"),e("OutboundLink")],1),t._v(" on Github for the complete API. The set of APIs available will grow in the near future as more APIs are added. This article can also be used as a guide to add new methods to the existing bdk-rn project.")]),t._v(" "),e("p",[t._v("The objective of "),e("code",[t._v("bdk-rn")]),t._v(" is to enable React Native developers to quickly start developing applications without the need to package BDK as described above.")]),t._v(" "),e("p",[t._v("Be on the lookout for user guides and tutorials on how to build bitcoin applications using "),e("code",[t._v("bdk-rn")]),t._v(" and "),e("code",[t._v("bdk-flutter")]),t._v(".")]),t._v(" "),e("h2",{attrs:{id:"references"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#references"}},[t._v("#")]),t._v(" References")]),t._v(" "),e("p",[t._v("Creating native modules for Android and iOS: "),e("a",{attrs:{href:"https://reactnative.dev/docs/native-modules-intro",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://reactnative.dev/docs/native-modules-intro"),e("OutboundLink")],1)]),t._v(" "),e("p",[t._v("React Native Architecture: "),e("a",{attrs:{href:"https://www.reactnative.guide/3-react-native-internals/3.1-react-native-internals.html",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://www.reactnative.guide/3-react-native-internals/3.1-react-native-internals.html"),e("OutboundLink")],1)]),t._v(" "),e("p",[t._v("BDK-Android API: "),e("a",{attrs:{href:"https://bitcoindevkit.org/bdk-jvm/bdk-jvm/org.bitcoindevkit/index.html",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://bitcoindevkit.org/bdk-jvm/bdk-jvm/org.bitcoindevkit/index.html"),e("OutboundLink")],1)]),t._v(" "),e("p",[t._v("BDK-RN: "),e("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://github.com/LtbLightning/bdk-rn"),e("OutboundLink")],1)]),t._v(" "),e("h2",{attrs:{id:"feedback"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#feedback"}},[t._v("#")]),t._v(" Feedback")]),t._v(" "),e("p",[t._v("The best way to give feedback on this would be to comment on the "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bitcoindevkit.org/pull/107",target:"_blank",rel:"noopener noreferrer"}},[t._v("pull request"),e("OutboundLink")],1),t._v(" for this blog post.\nThanks in advance.")])])}),[],!1,null,null,null);e.default=s.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[12],{323:function(t,e,a){t.exports=a.p+"assets/img/BDK-RN-Architecture.42fbc351.png"},324:function(t,e,a){t.exports=a.p+"assets/img/BDK-RN.370f20c3.png"},325:function(t,e,a){t.exports=a.p+"assets/img/android_folder.0ff999be.png"},371:function(t,e,a){"use strict";a.r(e);var n=a(7),s=Object(n.a)({},(function(){var t=this,e=t._self._c;return e("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[e("p",[t._v("The "),e("strong",[t._v("BitcoinDevkit")]),t._v("'s "),e("strong",[t._v("React Native")]),t._v(" library ("),e("code",[t._v("bdk-rn")]),t._v(") makes it easy to develop bitcoin applications for both Android and iOS mobile platforms. Using "),e("code",[t._v("bdk-rn")]),t._v(", knowledge of the underlying bitcoin and BDK API is not required and using "),e("code",[t._v("bdk-rn")]),t._v(" is similar to using any other RN module. The goal is "),e("strong",[t._v("Rapid Bitcoin Application Development")]),t._v(" by doing the heavy lifting in advance and providing a reusable library for other developers to use. Developers simply install using "),e("code",[t._v("yarn add")]),t._v(" and start using it in a React Native Project. The native code, Rust lang implementation, configuration and other setup details are all taken care of by "),e("code",[t._v("bdk-rn")]),t._v(".")]),t._v(" "),e("p",[t._v("This article is "),e("strong",[t._v("NOT a guide on how to use bdk-rn")]),t._v(" to build a bitcoin application, rather this is an insight into how "),e("code",[t._v("bdk-rn")]),t._v(" was developed. For help on how to use "),e("code",[t._v("bdk-rn")]),t._v(" to develop a bitcoin wallet or application please refer to the user guide in the "),e("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#usage",target:"_blank",rel:"noopener noreferrer"}},[t._v("readme"),e("OutboundLink")],1),t._v(" on Github. There will be "),e("code",[t._v("how to guides")]),t._v(" published shortly on getting started with "),e("code",[t._v("bdk-rn")]),t._v(".")]),t._v(" "),e("h2",{attrs:{id:"react-native-architecture"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#react-native-architecture"}},[t._v("#")]),t._v(" React Native Architecture")]),t._v(" "),e("p",[t._v("At a high level, RN consists of the UI front which is essentially JavaScript which interacts with the native iOS and Android platforms over a bridge. When communicating over the bridge values from JS are converted to native and vice versa.")]),t._v(" "),e("p",[t._v("The native part of RN consists of Android as well as iOS modules and components. The Android and iOS sections are full fledged native projects which interact with the JS side over the native bridge. A RN project has all the build configuraiton required to build both Android and iOS projects.")]),t._v(" "),e("p",[t._v("For the purpose of making "),e("code",[t._v("bdk-rn")]),t._v(", "),e("code",[t._v("bdk-kotlin")]),t._v(" is used as the native Android module and "),e("code",[t._v("bdk-swift")]),t._v(" as the native iOS module. These are configured and wrapped in a RN Project as part of the platform specific native modules within the RN Project. This RN Project is then built to be a reusable React Native module.")]),t._v(" "),e("figure",[e("img",{attrs:{src:a(323),alt:""}})]),t._v(" "),e("h2",{attrs:{id:"native-integration"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#native-integration"}},[t._v("#")]),t._v(" Native Integration")]),t._v(" "),e("p",[t._v("In order to communicate to native modules on Android and iOS, React Native provides React Context API for Java/Kotlin as well as Swift. React Context API are used to build the interface to the native bridge allowing communication from JS to native modules.")]),t._v(" "),e("p",[t._v("bdk-rn uses React Context API plus some native code to wrap and enhance bdk-kotlin and bdk-swift APIs. The native code calls and interacts with the Android and iOS native modules which interface with the underlying mobile platform.")]),t._v(" "),e("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"20%"},attrs:{src:a(324)}}),t._v(" "),e("h2",{attrs:{id:"android-module"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#android-module"}},[t._v("#")]),t._v(" Android Module")]),t._v(" "),e("p",[t._v("We will go into the details of how the BDK Android Module is integrated, we wont cover iOS.")]),t._v(" "),e("p",[t._v("Starting off with a basic RN project. This project will be enhanced with bdk-kotlin and bdk-swift binaries and native code. For now lets go into the details for Android, iOS has similar steps to be done in Swift.")]),t._v(" "),e("p",[t._v("The Android native project is located under the root project folder.")]),t._v(" "),e("img",{staticStyle:{display:"block",margin:"0 auto",zoom:"120%"},attrs:{src:a(325)}}),t._v(" "),e("p",[t._v("Here we need to add a dependency in "),e("code",[t._v("build.gradle")]),t._v(" for bdk-kotlin's android native binary. This will enable bdk-kotlin to be downloaded and available as one of the native modules.")]),t._v(" "),e("div",{staticClass:"language-javascript extra-class"},[e("pre",{pre:!0,attrs:{class:"language-javascript"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: build.gradle")]),t._v("\n\nrepositories "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("mavenCentral")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\ndependencies "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//noinspection GradleDynamicVersion")]),t._v("\n implementation "),e("span",{pre:!0,attrs:{class:"token string"}},[t._v("'com.facebook.react:react-native:+'")]),t._v("\n\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// bitcoindevkit")]),t._v("\n implementation "),e("span",{pre:!0,attrs:{class:"token string"}},[t._v("'org.bitcoindevkit:bdk-android:0.7.1'")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("We will create an Android native module which will interact with "),e("code",[t._v("bdk-android")]),t._v(".\nThis is done by adding a new Kotlin file "),e("code",[t._v("BdkRnModule.kt")]),t._v(" inside "),e("code",[t._v("android/app/src/main/java/com/bdkrn/")]),t._v(" folder")]),t._v(" "),e("p",[t._v("This will be part of the native code for bdk-rn module.Here a new class will be created to encapsulate the interaction with bitcoindevkit's android native binary.")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" android"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("annotation"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("SuppressLint\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" android"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("util"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Log\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Arguments\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Promise "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("as")]),t._v(" Result\n")])])]),e("p",[e("code",[t._v("org.bitcoindevkit")]),t._v(" will also need to be imported here")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" org"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bitcoindevkit"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Wallet "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("as")]),t._v(" BdkWallet\n")])])]),e("p",[t._v("To use React Context API "),e("code",[t._v("com.facebook.react.bridge.*")]),t._v(" also needs to be imported")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),t._v("\n")])])]),e("p",[t._v("A new class needs to be defined here which will implement the React Context API")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("BdkRnModule")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("reactContext"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" ReactApplicationContext"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v("\n\t"),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("ReactContextBaseJavaModule")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("reactContext"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("override")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fun")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getName")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('"BdkRnModule"')])]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("With the base imports and class defined, we can start writing methods.\nThis will demonstrate how bdk native module will be called and how values will be returned to JS over the native bridge")]),t._v(" "),e("p",[t._v("Lets create a method that can be called from JaveScript, to do so we use the "),e("code",[t._v("@ReactMethod")]),t._v(" directive which is part of the React Context API. This will expose the method so that it can be called from JavaScript.")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token annotation builtin"}},[t._v("@ReactMethod")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fun")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" Promise"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n \n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("We need one more file to complete our native framework. A new Kotlin file, "),e("code",[t._v("BdkRnPackage.kt")]),t._v(" is required to package all our native code into a new android module, here we specify the name of the file we just crated as the module name("),e("code",[t._v("BdkRnModule")]),t._v("). This can be done by adding the following code:")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnPackage.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("ReactPackage\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" com"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("facebook"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("react"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("bridge"),e("span",{pre:!0,attrs:{class:"token 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keyword"}},[t._v("return")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("mutableListOf")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("BdkRnModule")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("reactContext"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),e("p",[t._v("Now lets add code for creating a wallet in BdkRnModule.kt")]),t._v(" "),e("p",[t._v("The methods used here are for bdk-kotlin and available in the bdk-kotlin documentation.")]),t._v(" "),e("p",[t._v("We first create a key info object")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// File: BdkRnModule.kt")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token annotation builtin"}},[t._v("@ReactMethod")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fun")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" Promise"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Create key info with a new mnemonic")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" keys"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" ExtendedKeyInfo "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("generateExtendedKey")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n Network"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("TESTNET"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n WordCount"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("WORDS12"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('""')])]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n \n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// more code to follow...")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create descriptor and change descriptor")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create databaseConfig and blockchainconfig")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create wallet")]),t._v("\n \n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("p",[t._v("Then key info used to create a wallet descriptor and change descriptor:")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" descriptor"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" String "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('"wpkh("')])]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" keys"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("xprv "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(' "'),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("84")]),t._v("'"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v("'"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),t._v("'"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("/")]),e("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("/*)\"\n\nval changeDescriptor: String = descriptor.replace(\"/84'/1'/0'/0/*\",\"/84'/1'/0'/1/*\")\n")])])])]),e("p",[t._v("To create a wallet with bdk we need to specify wallet descriptor, network, a database config, blockchain config. We intend to use bitcoin testnet and want to use default memory for data. For bitcoin node we will use a public electrum server. We will need to define these parameters to create a wallet.")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" network "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" `Network"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("TESTNET`\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" databaseConfig "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" DatabaseConfig"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Memory\nblockchainConfig "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v("\n BlockchainConfig"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("Electrum")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("ElectrumConfig")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token string-literal singleline"}},[e("span",{pre:!0,attrs:{class:"token string"}},[t._v('"ssl://electrum.blockstream.info:60002"')])]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("null")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" 5u"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("null")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" 10u"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("Once done we can use these parameters to create a BDK wallet using the native android BDK library:")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")]),t._v(" wallet"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" BdkWallet "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("BdkWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n descriptor"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n changeDescriptor"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("setNetwork")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("network"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n databaseConfig"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n config\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("Once we have a wallet initialised, we can call methods on it to sync, generate a new address and to get balance")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[t._v("wallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("sync")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("ProgressLog"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" maxAddress"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n\nwallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getNewAddress")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n\nwallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getBalance")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("toLong")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("To return a value from the native android code to React Native’s Javascript side over the JS Native bridge we will use "),e("code",[t._v("com.facebook.react.bridge.Promise")]),t._v(". To return balance information to JS, the following code can be used")]),t._v(" "),e("div",{staticClass:"language-kotlin extra-class"},[e("pre",{pre:!0,attrs:{class:"language-kotlin"}},[e("code",[e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("val")]),t._v(" balance"),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),t._v(" String "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" wallet"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("getBalance")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("toLong")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\nresult"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("resolve")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("balance"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),e("p",[t._v("At this point we have an Android native module and it can be invoked from JS by calling "),e("code",[t._v("createWallet")]),t._v(" and it will return the balance.")]),t._v(" "),e("p",[t._v("This project can be imported into any RN project to reuse the defined "),e("code",[t._v("createWallet")]),t._v(" method without the need to carry out the setup described above.")]),t._v(" "),e("div",{staticClass:"language-javascript extra-class"},[e("pre",{pre:!0,attrs:{class:"language-javascript"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// any js file in React Native")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" BdkRn "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("from")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token string"}},[t._v("'bdk-rn'")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create a wallet and retrieve current balance")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" balance "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),t._v(" BdkRn"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("createWallet")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nconsole"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("log")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v(" balance "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n\n")])])]),e("p",[t._v("The actual "),e("code",[t._v("bdk-rn")]),t._v(" module has organised the native code into granular methods for different stages of creating a wallet and for different interactions and use cases for a bitcoin application, like generating, mnemonic, keys, creating wallet for different networks, creating descriptors, creating or restoring wallet, fetching balance, fetching transactions and many other methods. Please refer to the "),e("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn#usage",target:"_blank",rel:"noopener noreferrer"}},[t._v("user guide in the readme"),e("OutboundLink")],1),t._v(" on Github for the complete API. The set of APIs available will grow in the near future as more APIs are added. This article can also be used as a guide to add new methods to the existing bdk-rn project.")]),t._v(" "),e("p",[t._v("The objective of "),e("code",[t._v("bdk-rn")]),t._v(" is to enable React Native developers to quickly start developing applications without the need to package BDK as described above.")]),t._v(" "),e("p",[t._v("Be on the lookout for user guides and tutorials on how to build bitcoin applications using "),e("code",[t._v("bdk-rn")]),t._v(" and "),e("code",[t._v("bdk-flutter")]),t._v(".")]),t._v(" "),e("h2",{attrs:{id:"references"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#references"}},[t._v("#")]),t._v(" References")]),t._v(" "),e("p",[t._v("Creating native modules for Android and iOS: "),e("a",{attrs:{href:"https://reactnative.dev/docs/native-modules-intro",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://reactnative.dev/docs/native-modules-intro"),e("OutboundLink")],1)]),t._v(" "),e("p",[t._v("React Native Architecture: "),e("a",{attrs:{href:"https://www.reactnative.guide/3-react-native-internals/3.1-react-native-internals.html",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://www.reactnative.guide/3-react-native-internals/3.1-react-native-internals.html"),e("OutboundLink")],1)]),t._v(" "),e("p",[t._v("BDK-Android API: "),e("a",{attrs:{href:"https://bitcoindevkit.org/bdk-jvm/bdk-jvm/org.bitcoindevkit/index.html",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://bitcoindevkit.org/bdk-jvm/bdk-jvm/org.bitcoindevkit/index.html"),e("OutboundLink")],1)]),t._v(" "),e("p",[t._v("BDK-RN: "),e("a",{attrs:{href:"https://github.com/LtbLightning/bdk-rn",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://github.com/LtbLightning/bdk-rn"),e("OutboundLink")],1)]),t._v(" "),e("h2",{attrs:{id:"feedback"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#feedback"}},[t._v("#")]),t._v(" Feedback")]),t._v(" "),e("p",[t._v("The best way to give feedback on this would be to comment on the "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bitcoindevkit.org/pull/107",target:"_blank",rel:"noopener noreferrer"}},[t._v("pull request"),e("OutboundLink")],1),t._v(" for this blog post.\nThanks in advance.")])])}),[],!1,null,null,null);e.default=s.exports}}]); \ No newline at end of file diff --git a/assets/js/16.3205896a.js b/assets/js/16.d887c7a3.js similarity index 99% rename from assets/js/16.3205896a.js rename to assets/js/16.d887c7a3.js index 4ae507c339..88a91ae06d 100644 --- a/assets/js/16.3205896a.js +++ b/assets/js/16.d887c7a3.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[16],{324:function(t,e,a){t.exports=a.p+"assets/img/descriptor-tracker.5942c853.jpg"},325:function(t,e,a){t.exports=a.p+"assets/img/checkpoints.a4179787.jpg"},367:function(t,e,a){"use strict";a.r(e);var s=a(7),n=Object(s.a)({},(function(){var t=this,e=t._self._c;return e("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[e("p",[t._v("The Bitcoin Devkit (BDK) lets you do a lot of useful things through convenient high level\nabstractions. It works great when these abstractions map nicely onto what you are trying to do. My\ngoal is to develop a new "),e("code",[t._v("bdk_core")]),t._v(" library for when they don't. I want "),e("code",[t._v("bdk_core")]),t._v(" to expose all the\nuseful "),e("em",[t._v("mechanisms")]),t._v(" that BDK has inside it without them being tied to any particular usage "),e("em",[t._v("policy")]),t._v("\nand with very minimal dependencies.")]),t._v(" "),e("p",[t._v("The "),e("code",[t._v("bdk_core")]),t._v(' idea is still "in the lab". We\'re not sure yet whether '),e("code",[t._v("bdk_core")]),t._v(" will just be what's\nleft of "),e("code",[t._v("bdk")]),t._v(" once we spin off all the components that have extra dependencies into their own crates\nand refine it a bit. In that case "),e("code",[t._v("bdk_core")]),t._v(" will just be called "),e("code",[t._v("bdk v1.0.0")]),t._v(" or something. Or it might\nbe that "),e("code",[t._v("bdk")]),t._v(" lives on with its current APIs and uses stuff "),e("code",[t._v("bdk_core")]),t._v(" to implement it internally.")]),t._v(" "),e("h2",{attrs:{id:"the-separation-of-policy-and-mechanism"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#the-separation-of-policy-and-mechanism"}},[t._v("#")]),t._v(" The separation of policy and mechanism")]),t._v(" "),e("p",[t._v("My guiding principle for "),e("code",[t._v("bdk_core")]),t._v(" is the "),e("em",[t._v("separation of policy and mechanism")]),t._v(". This is\nwhat I mean by these terms:")]),t._v(" "),e("ul",[e("li",[e("em",[t._v("mechanism")]),t._v(": How you do a particular thing. Mechanism code is functional and doesn't change much.")]),t._v(" "),e("li",[e("em",[t._v("policy")]),t._v(": What you want to do. Policy code composes mechanisms to achieve something in\nan application.")])]),t._v(" "),e("p",[t._v("Here's a nice passage about why the designers of the "),e("a",{attrs:{href:"https://en.wikipedia.org/wiki/X_Window_System",target:"_blank",rel:"noopener noreferrer"}},[t._v("X window system"),e("OutboundLink")],1),t._v(" applied this principle. X has\nbeen around since 1984 and doesn't look like it's going anywhere so it probably has a lot to teach us.\nFrom "),e("em",[e("a",{attrs:{href:"https://en.wikipedia.org/wiki/The_Art_of_Unix_Programming",target:"_blank",rel:"noopener noreferrer"}},[t._v("The Art of UNIX Programming"),e("OutboundLink")],1)]),t._v(":")]),t._v(" "),e("blockquote",[e("p",[t._v("...we observed that the designers of X made a basic decision to implement “mechanism, not policy”—to\nmake X a generic graphics engine and leave decisions about user-interface style to toolkits and\nother levels of the system. We justified this by pointing out that policy and mechanism tend to\nmutate on different timescales, with policy changing much faster than mechanism. Fashions in the\nlook and feel of GUI toolkits may come and go, but raster operations and compositing are forever.")])]),t._v(" "),e("blockquote",[e("p",[t._v("Thus, hardwiring policy and mechanism together has two bad effects: It makes policy rigid and\nharder to change in response to user requirements, and it means that trying to change policy has a\nstrong tendency to destabilize the mechanisms.")])]),t._v(" "),e("blockquote",[e("p",[t._v("On the other hand, by separating the two we make it\npossible to experiment with new policy without breaking mechanisms. We also make it much easier to\nwrite good tests for the mechanism (policy, because it ages so quickly, often does not justify the\ninvestment).")])]),t._v(" "),e("ul",[e("li",[t._v("[ ] > This design rule has wide application outside the GUI context. In general, it implies that we")])]),t._v(" "),e("blockquote",[e("p",[t._v("should look for ways to separate interfaces from engines.")])]),t._v(" "),e("p",[t._v("You'll notice we have a similar situation in Bitcoin engineering. We have mechanism code like\nsigning algorithms, key derivation, transaction construction logic, etc., that don't change much. But\nhow these compose together in applications changes quickly over time and between applications.")]),t._v(" "),e("p",[t._v("The main culprit of policy and mechanism conflation in "),e("code",[t._v("bdk")]),t._v(" is the main "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/struct.Wallet.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Wallet")]),e("OutboundLink")],1),t._v(" type.\nWallets do all of the following:")]),t._v(" "),e("ol",[e("li",[t._v("Store one or two descriptors (external and optional internal).")]),t._v(" "),e("li",[t._v("Keep track of which addresses you've given out so you only give out fresh ones from each descriptor.")]),t._v(" "),e("li",[t._v("Keep a list of transactions associated with the addresses in the wallet.")]),t._v(" "),e("li",[t._v("Given a source of blockchain data it can update its internal list of transactions.")]),t._v(" "),e("li",[t._v("Given some parameters it can build a PSBT from transaction outputs.")]),t._v(" "),e("li",[t._v("Given a PSBT it can sign it with its "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/signer/index.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Signers")]),e("OutboundLink")],1),t._v(".")])]),t._v(" "),e("p",[t._v("All of that is very useful but it is bound together with the particular policies and opinions of "),e("code",[t._v("Wallet")]),t._v(".\nIf "),e("code",[t._v("Wallet")]),t._v("'s policy is not your policy it's going to be tricky to get it to do what you want.\nHere are some examples:")]),t._v(" "),e("ol",[e("li",[t._v("In order to control how the "),e("code",[t._v("Wallet")]),t._v(" will select coins for a transaction internally you have to\npass in something implementing the "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/coin_selection/trait.CoinSelectionAlgorithm.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("CoinSelectionAlgorithm")]),e("OutboundLink")],1),t._v(" trait. A coin selection algorithm\nis clearly mechanism code but the policy of "),e("code",[t._v("Wallet")]),t._v(" restricts that mechanism's interface. We\nhave "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/281",target:"_blank",rel:"noopener noreferrer"}},[t._v("very old issues"),e("OutboundLink")],1),t._v(" related to what the\ninterface of this trait should be and we don't have a clear way forward. In "),e("code",[t._v("bdk_core")]),t._v(" I want to\npurely provide the coin selection mechanisms for figuring out whether you need to select more\nUTXOs or whether you need a change output etc. How you use that mechanism will be up to you.")]),t._v(" "),e("li",[t._v("Another trait that has a similar structure is the "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/signer/index.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Signer")]),e("OutboundLink")],1),t._v(" trait. You have to pass in signers\nso your wallet can sign PSBTs but you have little control over how the wallet chooses which\nsigners to use in any given situation. Right now the wallet will just iterate through all the\nsigners and ask them to sign. This is not always appropriate. In "),e("code",[t._v("bdk_core")]),t._v(" I want to provide\nfunctions for populating PSBTs given something that can sign. You'll be in control of when they\nget called.")])]),t._v(" "),e("h2",{attrs:{id:"a-syncing-mechansim-without-the-policy"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#a-syncing-mechansim-without-the-policy"}},[t._v("#")]),t._v(" A syncing mechansim without the policy")]),t._v(" "),e("p",[t._v("Syncing in "),e("code",[t._v("bdk")]),t._v(" is the place where the design of "),e("code",[t._v("Wallet")]),t._v(" is most restrictive. The "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/blockchain/trait.WalletSync.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("WalletSync")]),e("OutboundLink")],1),t._v("\ntrait forces you to sync all addresses in a wallet in one big batch. But this is not always what you\nwant to do. I spoke to a developer who wanted to sync his wallet slowly over time with each address\nbeing queried over a different Tor connection. It would be really difficult to implement\n"),e("code",[t._v("WalletSync")]),t._v(" with such a strategy. Another example where "),e("code",[t._v("WalletSync")]),t._v(" isn't the right fit is the\n"),e("a",{attrs:{href:"https://l2.technology/sensei",target:"_blank",rel:"noopener noreferrer"}},[t._v("Sensei"),e("OutboundLink")],1),t._v(" project which uses BDK but incrementally updates the database whenever new information\ncomes in from the blockchain.")]),t._v(" "),e("p",[t._v("Even if syncing all addresses at the same time is roughly what you want to do "),e("code",[t._v("WalletSync")]),t._v(" still\ngets in the way since it defines whether you do it synchronously or asynchrononusly. Applications\ncan control this through "),e("code",[t._v("bdk")]),t._v("'s "),e("code",[t._v("async-interface")]),t._v(" feature flag which internally changes the trait\ndefinition through macros. Another annoyance is that when using "),e("code",[t._v("async-interface")]),t._v(" the future that\ngets returned from "),e("code",[t._v("WalletSync")]),t._v(" "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/165",target:"_blank",rel:"noopener noreferrer"}},[t._v("cannot be "),e("code",[t._v("Send")]),e("OutboundLink")],1),t._v("\nbecause of how "),e("code",[t._v("Wallet")]),t._v(" handles database mutability internally, meaning you can't spawn the future\ninto a new thread.")]),t._v(" "),e("h3",{attrs:{id:"a-general-syncing-mechanism"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#a-general-syncing-mechanism"}},[t._v("#")]),t._v(" A general syncing mechanism")]),t._v(" "),e("p",[t._v("So what is the most general syncing mechanism that solves these problems? These are the things I\nthink it has to do regardless of where the blockchain data comes from or how it's stored:")]),t._v(" "),e("ol",[e("li",[t._v("Generate and store addresses.")]),t._v(" "),e("li",[t._v("Index transaction data, e.g. transaction outputs we own, when/if they were spent, etc.")]),t._v(" "),e("li",[t._v("Keep track of which addresses have been given out and which have been used.")]),t._v(" "),e("li",[t._v('Be able to "roll back" our view of the above data if a reorg makes some of it stale.')]),t._v(" "),e("li",[t._v("Keep track of transactions related our addresses in our mempool.")])]),t._v(" "),e("p",[t._v("Let's talk about how to implement a mechanism that does all that.")]),t._v(" "),e("h3",{attrs:{id:"how-to-store-and-index-transactions"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#how-to-store-and-index-transactions"}},[t._v("#")]),t._v(" How to store and index transactions")]),t._v(" "),e("p",[t._v("Different persistent storage backends have different APIs and their own indexing strategies. That's\nwhy the "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/database/trait.Database.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Database")]),e("OutboundLink")],1),t._v(" trait exists in BDK, to make a clean API to the different storage engines. It's\nimportant to note that the database in BDK only holds public data that could always be retrieved\nfrom the chain. It's just a cache. Despite this we support different backends. Right now it is a\nlot of work to add a new index to the data since you have to add it to every backend and you might have\nto apply schema changes (we still "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/359",target:"_blank",rel:"noopener noreferrer"}},[t._v("don't have a standard approach to\nthis"),e("OutboundLink")],1),t._v(").")]),t._v(" "),e("p",[t._v("Thomas Eizinger "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/165#issuecomment-1047483895",target:"_blank",rel:"noopener noreferrer"}},[t._v("suggested"),e("OutboundLink")],1),t._v("\ndoing everything in memory and only writing to persistent storage when it was convenient. It took me\nsome time but I came around to this idea. It would allow us to get rid of the "),e("code",[t._v("Database")]),t._v(" trait (at\nleast at the "),e("code",[t._v("bdk_core")]),t._v(" level) and greatly simplify what the persistent storage layer has to do.\nWhenever the data is loaded from persistent storage we can just do the indexing in memory and\npresent it to the application.")]),t._v(" "),e("p",[e("em",[t._v("But wait! Wouldn't this mean we'd use way more memory than we need to?")]),t._v(" Yes but memory is cheap.\nConsider that if we say the average transaction size is 300 bytes then with all our indexes each\ntransaction might cost 1kb of memory (pessimistically). This means we could index one thousand\ntransactions in a single megabyte! My iPhone has 4gb of memory so it could index a million\ntransactions with plenty of memory to spare. "),e("em",[t._v("But what if some users can't afford an iPhone?")]),t._v(" Then\nthey also couldn't have afforded to have made a million Bitcoin transactions! "),e("em",[t._v("But what about memory\nconstrained devices like hardware wallets!?")]),t._v(" Those devices typically don't store and retrieve\ntransactions. They're usually just signing devices. Perhaps one day someone will build a memory\nconstrained device that needs to do this work but until then I think this is a fine approach to\ntake.")]),t._v(" "),e("p",[t._v("For now I'm calling this thing that does the in-memory indexing of transactions related to a single\ndescriptor a "),e("code",[t._v("DescriptorTracker")]),t._v(". Here's a diagram that communicates how I imagine it relates to the\nother components.")]),t._v(" "),e("figure",[e("img",{attrs:{src:a(324),alt:""}})]),t._v(" "),e("h3",{attrs:{id:"rolling-back-rolling-forward-and-syncing-to-disk"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#rolling-back-rolling-forward-and-syncing-to-disk"}},[t._v("#")]),t._v(" Rolling back, rolling forward and syncing to disk")]),t._v(" "),e("p",[t._v("State changes in blockchains are clearly delineated. They all happen in blocks! Every view of the\nblockchain, whether you're getting it through compact block filters, an electrum server or something\nwacky like a utreexo bridge will have a concept of blocks and transactions in them. For a wallet we\nonly need a very sparse view of the blockchain that includes at which block a set of transactions\nexisted. That way, if a block disappears we know that all those transactions might disappear too.")]),t._v(" "),e("p",[t._v("With "),e("code",[t._v("bdk_core")]),t._v(" I want to introduce the concept of a "),e("em",[t._v("checkpoint")]),t._v(", which is a block height and hash and\na set of txids that were present at that height "),e("strong",[t._v("but not present in the previous checkpoint")]),t._v(". In\nthis way we create an append-only data structure that can easily be rolled back to a previous height\nif there is a reorg. After rolling back we can then roll forward and apply the new blocks.")]),t._v(" "),e("p",[t._v("Here's an example of how this idea works:")]),t._v(" "),e("figure",[e("img",{attrs:{src:a(325),alt:""}})]),t._v(" "),e("p",[t._v("There are a few edge cases I'd like to cover:")]),t._v(" "),e("ol",[e("li",[t._v("What if when gathering new data from the chain to update a "),e("code",[t._v("DescriptorTracker")]),t._v(" we find an old transaction that belongs to an earlier checkpoint that we had missed form our earlier syncs?")]),t._v(" "),e("li",[t._v("What if when we go to write to persistent storage from a "),e("code",[t._v("DescriptorTracker")]),t._v(" we find that it has some transactions the tracker doesn't? Should we try and reconcile the two sets of transactions?")])]),t._v(" "),e("p",[t._v("I think the correct approach is to treat the chain data as the source of truth for the\n"),e("code",[t._v("DescriptorTracker")]),t._v(" and the "),e("code",[t._v("DescriptorTracker")]),t._v(" as the source of truth for persistent storage. That\nis in the case of (1) we should just rollback the "),e("code",[t._v("DescriptorTracker")]),t._v(" and insert the old but\nrecently discovered transaction in the right place. In the case of (2) we should roll back the\npersistent storage to the point where it differs and apply changes from there. This implies that you\nshould only keep one instance of a "),e("code",[t._v("DescriptorTracker")]),t._v(" for a descriptor in your application and only\nupdate persistent storage by first applying the changes to the tracker.")]),t._v(" "),e("h2",{attrs:{id:"examples"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#examples"}},[t._v("#")]),t._v(" Examples")]),t._v(" "),e("p",[t._v("Here are some examples of what I think this may end up looking like in code. Keep in mind that if\nthis looks complicated it will probably be more complicated in practice! This doesn't mean that we\ncan't create simplifying abstractions and tools around these primitives to cover common policies. I hope we can implement "),e("code",[t._v("Wallet")]),t._v(" with "),e("code",[t._v("DescriptorTracker")]),t._v("s internally.")]),t._v(" "),e("h3",{attrs:{id:"doing-an-initial-sync-of-a-descriptor-that-may-already-contain-coins"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#doing-an-initial-sync-of-a-descriptor-that-may-already-contain-coins"}},[t._v("#")]),t._v(" Doing an initial sync of a descriptor that may already contain coins")]),t._v(" "),e("p",[t._v("When we first sync a descriptor that may already contain coins we want to iterate over all the\nscripts of the wallet and then stop if there's a big enough gap (e.g. 20). In this example we use an\nstateless "),e("a",{attrs:{href:"https://mempool.space/docs/api/rest",target:"_blank",rel:"noopener noreferrer"}},[t._v("esplora-like API"),e("OutboundLink")],1),t._v(".")]),t._v(" "),e("div",{staticClass:"language-rust extra-class"},[e("pre",{pre:!0,attrs:{class:"language-rust"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create a descriptor tracker the external addresses of a BIP86 key")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("let")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("mut")]),t._v(" tracker "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DescriptorTracker")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("new")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token string"}},[t._v("\"tr([73c5da0a/86'/0'/0']xpub6BgBgsespWvERF3LHQu6CnqdvfEvtMcQjYrcRzx53QJjSxarj2afYWcLteoGVky7D3UKDP9QyrLprQ3VCECoY49yfdDEHGCtMMj92pReUsQ/0/*)\"")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("let")]),t._v(" esplora "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("bdk_esplora"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")])]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Client")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("new")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token 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punctuation"}},[t._v(";")]),t._v("\n")])])]),e("h3",{attrs:{id:"doing-a-sync-of-a-wallet-after-you-already-have-syncd"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#doing-a-sync-of-a-wallet-after-you-already-have-syncd"}},[t._v("#")]),t._v(" Doing a sync of a wallet after you already have sync'd")]),t._v(" "),e("p",[t._v("Now imagine you just want to check if any UTXOs in your wallet have been spent. In this case we've\nalready sync'd before so we need to load that data into the tracker from disk first (rather than\ngoing straight to the blockchain). Then we just ask esplora for transactions related to these\ntransaction outputs.")]),t._v(" "),e("div",{staticClass:"language-rust extra-class"},[e("pre",{pre:!0,attrs:{class:"language-rust"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create a descriptor tracker the external addresses of a BIP86 key")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("let")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("mut")]),t._v(" tracker "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DescriptorTracker")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("new")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token 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"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("h3",{attrs:{id:"updating-state-when-you-get-the-data-in-real-time"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#updating-state-when-you-get-the-data-in-real-time"}},[t._v("#")]),t._v(" Updating state when you get the data in real time")]),t._v(" "),e("p",[t._v("If you have an event based view of the blockchain that feeds you block connected or block\ndisconnected events then I imagine the API would look something like this.\nThere's quite a bit left out here but I hope you get the idea.")]),t._v(" "),e("div",{staticClass:"language-rust extra-class"},[e("pre",{pre:!0,attrs:{class:"language-rust"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create a descriptor tracker the external addresses of a BIP86 key")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("let")]),t._v(" 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punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("await")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("match")]),t._v(" blockchain_event "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BlockChainEvent")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Connected")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("new_block"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("match")]),t._v(" tracker"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("apply_block")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("new_block"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Ok")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("modified"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" modified "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// update persistent storage from tracker")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Err")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ApplyBlockError")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("OutOfOrder")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// the block event we got was not the next block we expected.")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// How to recover from this will depend on the application and block source")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BlockchainEvent")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Disconnected")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("disconnected_height"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" disconnected_hash"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// this might invalidate a checkpoint")]),t._v("\n tracker"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("disconnect_block")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("disconnected_height"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" disconnected_hash"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Now apply to persistent storage")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])])]),e("h2",{attrs:{id:"feedback"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#feedback"}},[t._v("#")]),t._v(" Feedback")]),t._v(" "),e("p",[t._v("The best way to give feedback on this would be to comment on the "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bitcoindevkit.org/pull/100",target:"_blank",rel:"noopener noreferrer"}},[t._v("pull request"),e("OutboundLink")],1),t._v(" for this blog post.\nThanks in advance.")])])}),[],!1,null,null,null);e.default=n.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[16],{321:function(t,e,a){t.exports=a.p+"assets/img/descriptor-tracker.5942c853.jpg"},322:function(t,e,a){t.exports=a.p+"assets/img/checkpoints.a4179787.jpg"},365:function(t,e,a){"use strict";a.r(e);var s=a(7),n=Object(s.a)({},(function(){var t=this,e=t._self._c;return e("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[e("p",[t._v("The Bitcoin Devkit (BDK) lets you do a lot of useful things through convenient high level\nabstractions. It works great when these abstractions map nicely onto what you are trying to do. My\ngoal is to develop a new "),e("code",[t._v("bdk_core")]),t._v(" library for when they don't. I want "),e("code",[t._v("bdk_core")]),t._v(" to expose all the\nuseful "),e("em",[t._v("mechanisms")]),t._v(" that BDK has inside it without them being tied to any particular usage "),e("em",[t._v("policy")]),t._v("\nand with very minimal dependencies.")]),t._v(" "),e("p",[t._v("The "),e("code",[t._v("bdk_core")]),t._v(' idea is still "in the lab". We\'re not sure yet whether '),e("code",[t._v("bdk_core")]),t._v(" will just be what's\nleft of "),e("code",[t._v("bdk")]),t._v(" once we spin off all the components that have extra dependencies into their own crates\nand refine it a bit. In that case "),e("code",[t._v("bdk_core")]),t._v(" will just be called "),e("code",[t._v("bdk v1.0.0")]),t._v(" or something. Or it might\nbe that "),e("code",[t._v("bdk")]),t._v(" lives on with its current APIs and uses stuff "),e("code",[t._v("bdk_core")]),t._v(" to implement it internally.")]),t._v(" "),e("h2",{attrs:{id:"the-separation-of-policy-and-mechanism"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#the-separation-of-policy-and-mechanism"}},[t._v("#")]),t._v(" The separation of policy and mechanism")]),t._v(" "),e("p",[t._v("My guiding principle for "),e("code",[t._v("bdk_core")]),t._v(" is the "),e("em",[t._v("separation of policy and mechanism")]),t._v(". This is\nwhat I mean by these terms:")]),t._v(" "),e("ul",[e("li",[e("em",[t._v("mechanism")]),t._v(": How you do a particular thing. Mechanism code is functional and doesn't change much.")]),t._v(" "),e("li",[e("em",[t._v("policy")]),t._v(": What you want to do. Policy code composes mechanisms to achieve something in\nan application.")])]),t._v(" "),e("p",[t._v("Here's a nice passage about why the designers of the "),e("a",{attrs:{href:"https://en.wikipedia.org/wiki/X_Window_System",target:"_blank",rel:"noopener noreferrer"}},[t._v("X window system"),e("OutboundLink")],1),t._v(" applied this principle. X has\nbeen around since 1984 and doesn't look like it's going anywhere so it probably has a lot to teach us.\nFrom "),e("em",[e("a",{attrs:{href:"https://en.wikipedia.org/wiki/The_Art_of_Unix_Programming",target:"_blank",rel:"noopener noreferrer"}},[t._v("The Art of UNIX Programming"),e("OutboundLink")],1)]),t._v(":")]),t._v(" "),e("blockquote",[e("p",[t._v("...we observed that the designers of X made a basic decision to implement “mechanism, not policy”—to\nmake X a generic graphics engine and leave decisions about user-interface style to toolkits and\nother levels of the system. We justified this by pointing out that policy and mechanism tend to\nmutate on different timescales, with policy changing much faster than mechanism. Fashions in the\nlook and feel of GUI toolkits may come and go, but raster operations and compositing are forever.")])]),t._v(" "),e("blockquote",[e("p",[t._v("Thus, hardwiring policy and mechanism together has two bad effects: It makes policy rigid and\nharder to change in response to user requirements, and it means that trying to change policy has a\nstrong tendency to destabilize the mechanisms.")])]),t._v(" "),e("blockquote",[e("p",[t._v("On the other hand, by separating the two we make it\npossible to experiment with new policy without breaking mechanisms. We also make it much easier to\nwrite good tests for the mechanism (policy, because it ages so quickly, often does not justify the\ninvestment).")])]),t._v(" "),e("ul",[e("li",[t._v("[ ] > This design rule has wide application outside the GUI context. In general, it implies that we")])]),t._v(" "),e("blockquote",[e("p",[t._v("should look for ways to separate interfaces from engines.")])]),t._v(" "),e("p",[t._v("You'll notice we have a similar situation in Bitcoin engineering. We have mechanism code like\nsigning algorithms, key derivation, transaction construction logic, etc., that don't change much. But\nhow these compose together in applications changes quickly over time and between applications.")]),t._v(" "),e("p",[t._v("The main culprit of policy and mechanism conflation in "),e("code",[t._v("bdk")]),t._v(" is the main "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/struct.Wallet.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Wallet")]),e("OutboundLink")],1),t._v(" type.\nWallets do all of the following:")]),t._v(" "),e("ol",[e("li",[t._v("Store one or two descriptors (external and optional internal).")]),t._v(" "),e("li",[t._v("Keep track of which addresses you've given out so you only give out fresh ones from each descriptor.")]),t._v(" "),e("li",[t._v("Keep a list of transactions associated with the addresses in the wallet.")]),t._v(" "),e("li",[t._v("Given a source of blockchain data it can update its internal list of transactions.")]),t._v(" "),e("li",[t._v("Given some parameters it can build a PSBT from transaction outputs.")]),t._v(" "),e("li",[t._v("Given a PSBT it can sign it with its "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/signer/index.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Signers")]),e("OutboundLink")],1),t._v(".")])]),t._v(" "),e("p",[t._v("All of that is very useful but it is bound together with the particular policies and opinions of "),e("code",[t._v("Wallet")]),t._v(".\nIf "),e("code",[t._v("Wallet")]),t._v("'s policy is not your policy it's going to be tricky to get it to do what you want.\nHere are some examples:")]),t._v(" "),e("ol",[e("li",[t._v("In order to control how the "),e("code",[t._v("Wallet")]),t._v(" will select coins for a transaction internally you have to\npass in something implementing the "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/coin_selection/trait.CoinSelectionAlgorithm.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("CoinSelectionAlgorithm")]),e("OutboundLink")],1),t._v(" trait. A coin selection algorithm\nis clearly mechanism code but the policy of "),e("code",[t._v("Wallet")]),t._v(" restricts that mechanism's interface. We\nhave "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/281",target:"_blank",rel:"noopener noreferrer"}},[t._v("very old issues"),e("OutboundLink")],1),t._v(" related to what the\ninterface of this trait should be and we don't have a clear way forward. In "),e("code",[t._v("bdk_core")]),t._v(" I want to\npurely provide the coin selection mechanisms for figuring out whether you need to select more\nUTXOs or whether you need a change output etc. How you use that mechanism will be up to you.")]),t._v(" "),e("li",[t._v("Another trait that has a similar structure is the "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/wallet/signer/index.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Signer")]),e("OutboundLink")],1),t._v(" trait. You have to pass in signers\nso your wallet can sign PSBTs but you have little control over how the wallet chooses which\nsigners to use in any given situation. Right now the wallet will just iterate through all the\nsigners and ask them to sign. This is not always appropriate. In "),e("code",[t._v("bdk_core")]),t._v(" I want to provide\nfunctions for populating PSBTs given something that can sign. You'll be in control of when they\nget called.")])]),t._v(" "),e("h2",{attrs:{id:"a-syncing-mechansim-without-the-policy"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#a-syncing-mechansim-without-the-policy"}},[t._v("#")]),t._v(" A syncing mechansim without the policy")]),t._v(" "),e("p",[t._v("Syncing in "),e("code",[t._v("bdk")]),t._v(" is the place where the design of "),e("code",[t._v("Wallet")]),t._v(" is most restrictive. The "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/blockchain/trait.WalletSync.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("WalletSync")]),e("OutboundLink")],1),t._v("\ntrait forces you to sync all addresses in a wallet in one big batch. But this is not always what you\nwant to do. I spoke to a developer who wanted to sync his wallet slowly over time with each address\nbeing queried over a different Tor connection. It would be really difficult to implement\n"),e("code",[t._v("WalletSync")]),t._v(" with such a strategy. Another example where "),e("code",[t._v("WalletSync")]),t._v(" isn't the right fit is the\n"),e("a",{attrs:{href:"https://l2.technology/sensei",target:"_blank",rel:"noopener noreferrer"}},[t._v("Sensei"),e("OutboundLink")],1),t._v(" project which uses BDK but incrementally updates the database whenever new information\ncomes in from the blockchain.")]),t._v(" "),e("p",[t._v("Even if syncing all addresses at the same time is roughly what you want to do "),e("code",[t._v("WalletSync")]),t._v(" still\ngets in the way since it defines whether you do it synchronously or asynchrononusly. Applications\ncan control this through "),e("code",[t._v("bdk")]),t._v("'s "),e("code",[t._v("async-interface")]),t._v(" feature flag which internally changes the trait\ndefinition through macros. Another annoyance is that when using "),e("code",[t._v("async-interface")]),t._v(" the future that\ngets returned from "),e("code",[t._v("WalletSync")]),t._v(" "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/165",target:"_blank",rel:"noopener noreferrer"}},[t._v("cannot be "),e("code",[t._v("Send")]),e("OutboundLink")],1),t._v("\nbecause of how "),e("code",[t._v("Wallet")]),t._v(" handles database mutability internally, meaning you can't spawn the future\ninto a new thread.")]),t._v(" "),e("h3",{attrs:{id:"a-general-syncing-mechanism"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#a-general-syncing-mechanism"}},[t._v("#")]),t._v(" A general syncing mechanism")]),t._v(" "),e("p",[t._v("So what is the most general syncing mechanism that solves these problems? These are the things I\nthink it has to do regardless of where the blockchain data comes from or how it's stored:")]),t._v(" "),e("ol",[e("li",[t._v("Generate and store addresses.")]),t._v(" "),e("li",[t._v("Index transaction data, e.g. transaction outputs we own, when/if they were spent, etc.")]),t._v(" "),e("li",[t._v("Keep track of which addresses have been given out and which have been used.")]),t._v(" "),e("li",[t._v('Be able to "roll back" our view of the above data if a reorg makes some of it stale.')]),t._v(" "),e("li",[t._v("Keep track of transactions related our addresses in our mempool.")])]),t._v(" "),e("p",[t._v("Let's talk about how to implement a mechanism that does all that.")]),t._v(" "),e("h3",{attrs:{id:"how-to-store-and-index-transactions"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#how-to-store-and-index-transactions"}},[t._v("#")]),t._v(" How to store and index transactions")]),t._v(" "),e("p",[t._v("Different persistent storage backends have different APIs and their own indexing strategies. That's\nwhy the "),e("a",{attrs:{href:"https://docs.rs/bdk/latest/bdk/database/trait.Database.html",target:"_blank",rel:"noopener noreferrer"}},[e("code",[t._v("Database")]),e("OutboundLink")],1),t._v(" trait exists in BDK, to make a clean API to the different storage engines. It's\nimportant to note that the database in BDK only holds public data that could always be retrieved\nfrom the chain. It's just a cache. Despite this we support different backends. Right now it is a\nlot of work to add a new index to the data since you have to add it to every backend and you might have\nto apply schema changes (we still "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/359",target:"_blank",rel:"noopener noreferrer"}},[t._v("don't have a standard approach to\nthis"),e("OutboundLink")],1),t._v(").")]),t._v(" "),e("p",[t._v("Thomas Eizinger "),e("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk/issues/165#issuecomment-1047483895",target:"_blank",rel:"noopener noreferrer"}},[t._v("suggested"),e("OutboundLink")],1),t._v("\ndoing everything in memory and only writing to persistent storage when it was convenient. It took me\nsome time but I came around to this idea. It would allow us to get rid of the "),e("code",[t._v("Database")]),t._v(" trait (at\nleast at the "),e("code",[t._v("bdk_core")]),t._v(" level) and greatly simplify what the persistent storage layer has to do.\nWhenever the data is loaded from persistent storage we can just do the indexing in memory and\npresent it to the application.")]),t._v(" "),e("p",[e("em",[t._v("But wait! Wouldn't this mean we'd use way more memory than we need to?")]),t._v(" Yes but memory is cheap.\nConsider that if we say the average transaction size is 300 bytes then with all our indexes each\ntransaction might cost 1kb of memory (pessimistically). This means we could index one thousand\ntransactions in a single megabyte! My iPhone has 4gb of memory so it could index a million\ntransactions with plenty of memory to spare. "),e("em",[t._v("But what if some users can't afford an iPhone?")]),t._v(" Then\nthey also couldn't have afforded to have made a million Bitcoin transactions! "),e("em",[t._v("But what about memory\nconstrained devices like hardware wallets!?")]),t._v(" Those devices typically don't store and retrieve\ntransactions. They're usually just signing devices. Perhaps one day someone will build a memory\nconstrained device that needs to do this work but until then I think this is a fine approach to\ntake.")]),t._v(" "),e("p",[t._v("For now I'm calling this thing that does the in-memory indexing of transactions related to a single\ndescriptor a "),e("code",[t._v("DescriptorTracker")]),t._v(". Here's a diagram that communicates how I imagine it relates to the\nother components.")]),t._v(" "),e("figure",[e("img",{attrs:{src:a(321),alt:""}})]),t._v(" "),e("h3",{attrs:{id:"rolling-back-rolling-forward-and-syncing-to-disk"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#rolling-back-rolling-forward-and-syncing-to-disk"}},[t._v("#")]),t._v(" Rolling back, rolling forward and syncing to disk")]),t._v(" "),e("p",[t._v("State changes in blockchains are clearly delineated. They all happen in blocks! Every view of the\nblockchain, whether you're getting it through compact block filters, an electrum server or something\nwacky like a utreexo bridge will have a concept of blocks and transactions in them. For a wallet we\nonly need a very sparse view of the blockchain that includes at which block a set of transactions\nexisted. That way, if a block disappears we know that all those transactions might disappear too.")]),t._v(" "),e("p",[t._v("With "),e("code",[t._v("bdk_core")]),t._v(" I want to introduce the concept of a "),e("em",[t._v("checkpoint")]),t._v(", which is a block height and hash and\na set of txids that were present at that height "),e("strong",[t._v("but not present in the previous checkpoint")]),t._v(". In\nthis way we create an append-only data structure that can easily be rolled back to a previous height\nif there is a reorg. After rolling back we can then roll forward and apply the new blocks.")]),t._v(" "),e("p",[t._v("Here's an example of how this idea works:")]),t._v(" "),e("figure",[e("img",{attrs:{src:a(322),alt:""}})]),t._v(" "),e("p",[t._v("There are a few edge cases I'd like to cover:")]),t._v(" "),e("ol",[e("li",[t._v("What if when gathering new data from the chain to update a "),e("code",[t._v("DescriptorTracker")]),t._v(" we find an old transaction that belongs to an earlier checkpoint that we had missed form our earlier syncs?")]),t._v(" "),e("li",[t._v("What if when we go to write to persistent storage from a "),e("code",[t._v("DescriptorTracker")]),t._v(" we find that it has some transactions the tracker doesn't? Should we try and reconcile the two sets of transactions?")])]),t._v(" "),e("p",[t._v("I think the correct approach is to treat the chain data as the source of truth for the\n"),e("code",[t._v("DescriptorTracker")]),t._v(" and the "),e("code",[t._v("DescriptorTracker")]),t._v(" as the source of truth for persistent storage. That\nis in the case of (1) we should just rollback the "),e("code",[t._v("DescriptorTracker")]),t._v(" and insert the old but\nrecently discovered transaction in the right place. In the case of (2) we should roll back the\npersistent storage to the point where it differs and apply changes from there. This implies that you\nshould only keep one instance of a "),e("code",[t._v("DescriptorTracker")]),t._v(" for a descriptor in your application and only\nupdate persistent storage by first applying the changes to the tracker.")]),t._v(" "),e("h2",{attrs:{id:"examples"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#examples"}},[t._v("#")]),t._v(" Examples")]),t._v(" "),e("p",[t._v("Here are some examples of what I think this may end up looking like in code. Keep in mind that if\nthis looks complicated it will probably be more complicated in practice! This doesn't mean that we\ncan't create simplifying abstractions and tools around these primitives to cover common policies. I hope we can implement "),e("code",[t._v("Wallet")]),t._v(" with "),e("code",[t._v("DescriptorTracker")]),t._v("s internally.")]),t._v(" "),e("h3",{attrs:{id:"doing-an-initial-sync-of-a-descriptor-that-may-already-contain-coins"}},[e("a",{staticClass:"header-anchor",attrs:{href:"#doing-an-initial-sync-of-a-descriptor-that-may-already-contain-coins"}},[t._v("#")]),t._v(" Doing an initial sync of a descriptor that may already contain coins")]),t._v(" "),e("p",[t._v("When we first sync a descriptor that may already contain coins we want to iterate over all the\nscripts of the wallet and then stop if there's a big enough gap (e.g. 20). 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In this case we've\nalready sync'd before so we need to load that data into the tracker from disk first (rather than\ngoing straight to the blockchain). Then we just ask esplora for transactions related to these\ntransaction outputs.")]),t._v(" "),e("div",{staticClass:"language-rust extra-class"},[e("pre",{pre:!0,attrs:{class:"language-rust"}},[e("code",[e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// create a descriptor tracker the external addresses of a BIP86 key")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("let")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("mut")]),t._v(" tracker "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DescriptorTracker")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("new")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token 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punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("apply_block")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("new_block"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Ok")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("modified"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" modified "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// update persistent storage from tracker")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Err")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ApplyBlockError")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("OutOfOrder")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// the block event we got was not the next block we expected.")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// How to recover from this will depend on the application and block source")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BlockchainEvent")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("::")]),e("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Disconnected")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("disconnected_height"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" disconnected_hash"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=>")]),t._v(" "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// this might invalidate a checkpoint")]),t._v("\n tracker"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),e("span",{pre:!0,attrs:{class:"token function"}},[t._v("disconnect_block")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("disconnected_height"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" disconnected_hash"),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Now apply to persistent storage")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n "),e("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),e("span",{pre:!0,attrs:{class:"token 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t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This post is part 1 of 3 of a series. 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On the other hand, a fee rate too low would wait for a confirmation longer than planned or, even worse, the transaction could not be confirmed at all.")]),e._v(" "),t("h2",{attrs:{id:"the-problem"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-problem"}},[e._v("#")]),e._v(" The problem")]),e._v(" "),t("p",[e._v("Bitcoin Core offers fee estimation through the "),t("a",{attrs:{href:"https://bitcoincore.org/en/doc/0.20.0/rpc/util/estimatesmartfee/",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("estimatesmartfee")]),t("OutboundLink")],1),e._v(" RPC method, and there are also a lot of third-party "),t("a",{attrs:{href:"https://b10c.me/blog/003-a-list-of-public-bitcoin-feerate-estimation-apis/",target:"_blank",rel:"noopener noreferrer"}},[e._v("fee estimators"),t("OutboundLink")],1),e._v(" online, so do we need yet another estimator?")]),e._v(" "),t("p",[e._v("The model used by Bitcoin Core is not well suited for light-clients such as mobile wallets, even when running in pruned mode. Online estimators are lacking in terms of:")]),e._v(" "),t("ul",[t("li",[e._v("Privacy: Contacting the server leaks your IP (unless you are using Tor or a VPN), and the request timing may be used to correlate the request to a transaction broadcasted to the network soon thereafter.")]),e._v(" "),t("li",[e._v("Security: A malicious estimator could provide a high fee rate leading to a waste of money, or a low fee rate hampering the transaction confirmation.")])]),e._v(" "),t("p",[e._v("Replace By Fee (RBF) and Child Pays For Parent (CPFP) are techniques that can somewhat minimize the fee estimation problem, because one could simply underestimate the fee rate and then raise it when necessary, however:")]),e._v(" "),t("ul",[t("li",[e._v("RBF and CPFP may leak more information, such as patterns that may allow to detect the kind of wallet used, or which one of the transaction outputs is the change.")]),e._v(" "),t("li",[e._v('Requires additional interaction: the client must come back "online" to perform the fee bump. Sometimes this might be impractical or risky, for instance when using an offline signer or a multisignature with geographically distributed keys.')])]),e._v(" "),t("p",[e._v("Thus, this work is an effort to build a "),t("strong",[e._v("good fee estimator for purely peer to peer light clients")]),e._v(" such as "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[e._v("neutrino"),t("OutboundLink")],1),e._v(" based ones, or at least determine whether the approach we take is infeasible and open the discussion\nfor other, better, models.")]),e._v(" "),t("p",[e._v("In the meantime, another sub-goal is pursued: attract the interest of data scientists; Indeed the initial step for this analysis consists in constructing a data set, which could also also help kickstart other studies on fee estimation or, more broadly, on the Bitcoin mempool.")]),e._v(" "),t("h4",{attrs:{id:"the-challenges-and-the-solution"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-challenges-and-the-solution"}},[e._v("#")]),e._v(" The challenges and the solution")]),e._v(" "),t("p",[e._v("The hardest part of doing fee estimation on a light client is the lack of information: for example, Bitcoin Core's "),t("code",[e._v("estimatesmartfee")]),e._v(" uses up to the last 1008 blocks and knows everything about the mempool"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn2",id:"fnref2"}},[e._v("[2]")])]),e._v(", such as the fee rate of every transaction it contains, but a light-client does not.")]),e._v(" "),t("p",[e._v("Also, there are other factors that may help doing fee estimation, such as the day of the week (the mempool usually empties during the "),t("a",{attrs:{href:"https://www.blockchainresearchlab.org/2020/03/30/a-week-with-bitcoin-transaction-timing-and-transaction-fees/",target:"_blank",rel:"noopener noreferrer"}},[e._v("weekend"),t("OutboundLink")],1),e._v(") or the time of the day to anticipate recurring daily events\n(such as the batch of "),t("a",{attrs:{href:"https://b10c.me/mempool-observations/2-bitmex-broadcast-13-utc/",target:"_blank",rel:"noopener noreferrer"}},[e._v("bitmex withdrawals"),t("OutboundLink")],1),e._v(").")]),e._v(" "),t("p",[e._v("The idea is to apply Machine Learning (ML) techniques"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn3",id:"fnref3"}},[e._v("[3]")])]),e._v(" to discover patterns over what a light-client knows and see if they are enough to achieve consistently good estimations.")]),e._v(" "),t("h4",{attrs:{id:"the-question"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-question"}},[e._v("#")]),e._v(" The question")]),e._v(" "),t("p",[e._v('We are going to use a DNN (Deep Neural Network), a ML technique in the supervised learning branch. The "ELI5" is: give a lot of example inputs and the desired output to a black box; if there are correlations between inputs and outputs,\nand there are enough examples, the black box will eventually start predicting the correct output even with inputs it has never seen before.')]),e._v(" "),t("p",[e._v("To define our inputs and outputs, we need to start from the question we want to answer. For a fee estimator this is:")]),e._v(" "),t("p",[t("em",[e._v('"Which minimum fee rate should I use if I want this transaction to be confirmed in at most '),t("code",[e._v("n")]),e._v(' blocks?"')])]),e._v(" "),t("p",[e._v("This can be translated to a table with many rows like:")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("confirms_in")]),e._v(" "),t("th",[e._v("other_information")]),e._v(" "),t("th",[e._v("fee_rate")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("1")]),e._v(" "),t("td",[e._v("...")]),e._v(" "),t("td",[e._v("100.34")])]),e._v(" "),t("tr",[t("td",[e._v("2")]),e._v(" "),t("td",[e._v("...")]),e._v(" "),t("td",[e._v("84.33")])]),e._v(" "),t("tr",[t("td",[e._v("10")]),e._v(" "),t("td",[e._v("...")]),e._v(" "),t("td",[e._v("44.44")])])])]),e._v(" "),t("p",[e._v("where the "),t("code",[e._v("fee_rate")]),e._v(' column is the output we want, also called the "'),t("em",[e._v("target")]),e._v('" or "'),t("em",[e._v("label")]),e._v('" in ML terminology, and the other columns are our inputs.')]),e._v(" "),t("p",[e._v("Can we build this table just by looking at the Bitcoin blockchain? Unfortunately, we can't:\nThe main thing that's missing is an indication of when the node first saw a transaction that has been later confirmed in a block. With that knowledge we can say that the fee rate of that transaction was the exact value required to confirm\nwithin the number of blocks it actually took to be confirmed. For instance, if we see transaction "),t("code",[e._v("t")]),e._v(" when the blockchain is at height "),t("code",[e._v("1000")]),e._v(" and then we notice that "),t("code",[e._v("t")]),e._v(" has been included in block "),t("code",[e._v("1006")]),e._v(", we can deduce that the\nfee rate paid by "),t("code",[e._v("t")]),e._v(" was the exact value required to get confirmed within the next "),t("code",[e._v("6")]),e._v(" blocks.")]),e._v(" "),t("p",[e._v("So to build our model, we first need to gather these data, and machine learning needs a "),t("em",[e._v("lot")]),e._v(" of data to work well.")]),e._v(" "),t("h4",{attrs:{id:"the-data-logger"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-data-logger"}},[e._v("#")]),e._v(" The data logger")]),e._v(" "),t("p",[e._v("The "),t("a",{attrs:{href:"https://github.com/RCasatta/bitcoin_logger",target:"_blank",rel:"noopener noreferrer"}},[e._v("data logger"),t("OutboundLink")],1),e._v(" is built with the purpose of collecting all the data we need, and it's MIT licensed open source software written in Rust.")]),e._v(" "),t("p",[e._v("We need to register the moment in time when transactions enter in the node's mempool; to be efficient and precise we should not only call the RPC endpoints but listen to "),t("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/zmq.md",target:"_blank",rel:"noopener noreferrer"}},[e._v("ZMQ"),t("OutboundLink")],1),e._v(" events. Luckily, the just released bitcoin core 0.21.0 added a new "),t("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/zmq.md",target:"_blank",rel:"noopener noreferrer"}},[e._v("ZMQ"),t("OutboundLink")],1),e._v(" topic "),t("code",[e._v("zmqpubsequence")]),e._v(" notifying mempool events (and block events). The logger is also listening to "),t("code",[e._v("zmqpubrawtx")]),e._v(" and "),t("code",[e._v("zmqpubrawblock")]),e._v(" topics, to make less RPC calls.")]),e._v(" "),t("p",[e._v("We are not only interested in the timestamp of the transaction entering the mempool, but also how many blocks it will take until the same transaction is confirmed.\nIn the final dataset this field is called "),t("code",[e._v("confirms_in")]),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn4",id:"fnref4"}},[e._v("[4]")])]),e._v("; if "),t("code",[e._v("confirms_in = 1")]),e._v(" it means the transaction is confirmed in the first block created after it has been seen for the first time.")]),e._v(" "),t("p",[e._v("Another critical piece of information logged by the data logger is the "),t("code",[e._v("fee_rate")]),e._v(" of the transaction, since the absolute fee value paid by a bitcoin transaction is not available nor derivable given only the transaction itself, as the inputs don't have explicit amounts.")]),e._v(" "),t("p",[e._v("All these data (apart from the time of the transaction entering in the mempool) can actually be reconstructed simply by looking at the blockchain. However, querying the bitcoin node can be fairly slow, and during the model training iterations we want to recreate the ML dataset rapidly"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn5",id:"fnref5"}},[e._v("[5]")])]),e._v(", for example whenever we need to modify or add a new field.")]),e._v(" "),t("p",[e._v("For these reasons, the logger is split into two parts: a process listening to the events sent by our node, which creates raw logs, and then a second process that uses these logs to create the final CSV dataset.\nRaw logs are self-contained: for example, they contain all the previous transaction output values for every relevant transaction. This causes some redundancy, but in this case it's better to trade some efficiency for more performance\nwhen recreating the dataset.")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/high-level-graph.svg",alt:"High level graph"}})]),e._v(" "),t("p",[e._v("My logger instance started collecting data on the 18th of December 2020, and as of today (25th January 2020), the raw logs are about 16GB.")]),e._v(" "),t("p",[e._v("I expect (or at least hope) the raw logs, the CSV dataset, or the data logger will be useful also for other projects as well, like monitoring the propagation of transactions or other works involving raw mempool data. We will share raw logs data through torrent soon.")]),e._v(" "),t("p",[e._v("In the following "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-2/"}},[e._v("Part 2")]),e._v(" we are going to talk about the dataset.")],1),e._v(" "),t("hr",{staticClass:"footnotes-sep"}),e._v(" "),t("section",{staticClass:"footnotes"},[t("ol",{staticClass:"footnotes-list"},[t("li",{staticClass:"footnote-item",attrs:{id:"fn1"}},[t("p",[e._v("The transaction fee rate is the ratio between the absolute fee expressed in satoshi, over the weight of the transaction measured in virtual bytes. The weight of the transaction is similar to the byte size, however a part of the transaction (the segwit part) is discounted, their byte size is considered less because it creates less burden for the network. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref1"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn2"}},[t("p",[e._v("mempool is the set of transactions that are valid by consensus rules (for example, they are spending existing bitcoin), broadcasted in the bitcoin peer to peer network, but they are not yet part of the blockchain. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref2"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn3"}},[t("p",[e._v("DISCLAIMER: I am not an expert data-scientist! "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref3"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn4"}},[t("p",[e._v("Conceptually similar to bitcoin core "),t("code",[e._v("estimatesmartfee")]),e._v(' parameter called "blocks target", however, '),t("code",[e._v("confirms_in")]),e._v(" is the real value not the desired target. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref4"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn5"}},[t("p",[e._v("16GB of compressed raw logs are processed and a compressed CSV produced in about 5 minutes. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref5"}},[e._v("↩︎")])])])])])])}),[],!1,null,null,null);t.default=n.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[22],{367:function(e,t,a){"use strict";a.r(t);var o=a(7),n=Object(o.a)({},(function(){var e=this,t=e._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This post is part 1 of 3 of a series. ("),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-2/"}},[e._v("Part 2")]),e._v(", "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-3/"}},[e._v("Part 3")]),e._v(")")],1),e._v(" "),t("ul",[t("li",[t("a",{attrs:{href:"#introduction-what-is-fee-estimation"}},[e._v("Introduction: what is fee estimation?")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#the-problem"}},[e._v("The problem")]),e._v(" "),t("ul",[t("li",[t("a",{attrs:{href:"#the-challenges-and-the-solution"}},[e._v("The challenges and the solution")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#the-question"}},[e._v("The question")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#the-data-logger"}},[e._v("The data logger")])])])])]),e._v(" "),t("h2",{attrs:{id:"introduction-what-is-fee-estimation"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#introduction-what-is-fee-estimation"}},[e._v("#")]),e._v(" Introduction: what is fee estimation?")]),e._v(" "),t("p",[e._v("Fee estimation is the process of selecting the fee rate"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn1",id:"fnref1"}},[e._v("[1]")])]),e._v(" for a bitcoin transaction being created, according to two main factors:")]),e._v(" "),t("ul",[t("li",[e._v("The current congestion of the Bitcoin network.")]),e._v(" "),t("li",[e._v("The urgency, or lack thereof, for the transaction confirmation, i.e, its inclusion in a block.")])]),e._v(" "),t("p",[e._v("A fee rate should be adequate to the above factors: a fee too high would be a waste of money, because the same result could have been achieved with a lower expense. On the other hand, a fee rate too low would wait for a confirmation longer than planned or, even worse, the transaction could not be confirmed at all.")]),e._v(" "),t("h2",{attrs:{id:"the-problem"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-problem"}},[e._v("#")]),e._v(" The problem")]),e._v(" "),t("p",[e._v("Bitcoin Core offers fee estimation through the "),t("a",{attrs:{href:"https://bitcoincore.org/en/doc/0.20.0/rpc/util/estimatesmartfee/",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("estimatesmartfee")]),t("OutboundLink")],1),e._v(" RPC method, and there are also a lot of third-party "),t("a",{attrs:{href:"https://b10c.me/blog/003-a-list-of-public-bitcoin-feerate-estimation-apis/",target:"_blank",rel:"noopener noreferrer"}},[e._v("fee estimators"),t("OutboundLink")],1),e._v(" online, so do we need yet another estimator?")]),e._v(" "),t("p",[e._v("The model used by Bitcoin Core is not well suited for light-clients such as mobile wallets, even when running in pruned mode. Online estimators are lacking in terms of:")]),e._v(" "),t("ul",[t("li",[e._v("Privacy: Contacting the server leaks your IP (unless you are using Tor or a VPN), and the request timing may be used to correlate the request to a transaction broadcasted to the network soon thereafter.")]),e._v(" "),t("li",[e._v("Security: A malicious estimator could provide a high fee rate leading to a waste of money, or a low fee rate hampering the transaction confirmation.")])]),e._v(" "),t("p",[e._v("Replace By Fee (RBF) and Child Pays For Parent (CPFP) are techniques that can somewhat minimize the fee estimation problem, because one could simply underestimate the fee rate and then raise it when necessary, however:")]),e._v(" "),t("ul",[t("li",[e._v("RBF and CPFP may leak more information, such as patterns that may allow to detect the kind of wallet used, or which one of the transaction outputs is the change.")]),e._v(" "),t("li",[e._v('Requires additional interaction: the client must come back "online" to perform the fee bump. Sometimes this might be impractical or risky, for instance when using an offline signer or a multisignature with geographically distributed keys.')])]),e._v(" "),t("p",[e._v("Thus, this work is an effort to build a "),t("strong",[e._v("good fee estimator for purely peer to peer light clients")]),e._v(" such as "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[e._v("neutrino"),t("OutboundLink")],1),e._v(" based ones, or at least determine whether the approach we take is infeasible and open the discussion\nfor other, better, models.")]),e._v(" "),t("p",[e._v("In the meantime, another sub-goal is pursued: attract the interest of data scientists; Indeed the initial step for this analysis consists in constructing a data set, which could also also help kickstart other studies on fee estimation or, more broadly, on the Bitcoin mempool.")]),e._v(" "),t("h4",{attrs:{id:"the-challenges-and-the-solution"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-challenges-and-the-solution"}},[e._v("#")]),e._v(" The challenges and the solution")]),e._v(" "),t("p",[e._v("The hardest part of doing fee estimation on a light client is the lack of information: for example, Bitcoin Core's "),t("code",[e._v("estimatesmartfee")]),e._v(" uses up to the last 1008 blocks and knows everything about the mempool"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn2",id:"fnref2"}},[e._v("[2]")])]),e._v(", such as the fee rate of every transaction it contains, but a light-client does not.")]),e._v(" "),t("p",[e._v("Also, there are other factors that may help doing fee estimation, such as the day of the week (the mempool usually empties during the "),t("a",{attrs:{href:"https://www.blockchainresearchlab.org/2020/03/30/a-week-with-bitcoin-transaction-timing-and-transaction-fees/",target:"_blank",rel:"noopener noreferrer"}},[e._v("weekend"),t("OutboundLink")],1),e._v(") or the time of the day to anticipate recurring daily events\n(such as the batch of "),t("a",{attrs:{href:"https://b10c.me/mempool-observations/2-bitmex-broadcast-13-utc/",target:"_blank",rel:"noopener noreferrer"}},[e._v("bitmex withdrawals"),t("OutboundLink")],1),e._v(").")]),e._v(" "),t("p",[e._v("The idea is to apply Machine Learning (ML) techniques"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn3",id:"fnref3"}},[e._v("[3]")])]),e._v(" to discover patterns over what a light-client knows and see if they are enough to achieve consistently good estimations.")]),e._v(" "),t("h4",{attrs:{id:"the-question"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-question"}},[e._v("#")]),e._v(" The question")]),e._v(" "),t("p",[e._v('We are going to use a DNN (Deep Neural Network), a ML technique in the supervised learning branch. The "ELI5" is: give a lot of example inputs and the desired output to a black box; if there are correlations between inputs and outputs,\nand there are enough examples, the black box will eventually start predicting the correct output even with inputs it has never seen before.')]),e._v(" "),t("p",[e._v("To define our inputs and outputs, we need to start from the question we want to answer. For a fee estimator this is:")]),e._v(" "),t("p",[t("em",[e._v('"Which minimum fee rate should I use if I want this transaction to be confirmed in at most '),t("code",[e._v("n")]),e._v(' blocks?"')])]),e._v(" "),t("p",[e._v("This can be translated to a table with many rows like:")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("confirms_in")]),e._v(" "),t("th",[e._v("other_information")]),e._v(" "),t("th",[e._v("fee_rate")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("1")]),e._v(" "),t("td",[e._v("...")]),e._v(" "),t("td",[e._v("100.34")])]),e._v(" "),t("tr",[t("td",[e._v("2")]),e._v(" "),t("td",[e._v("...")]),e._v(" "),t("td",[e._v("84.33")])]),e._v(" "),t("tr",[t("td",[e._v("10")]),e._v(" "),t("td",[e._v("...")]),e._v(" "),t("td",[e._v("44.44")])])])]),e._v(" "),t("p",[e._v("where the "),t("code",[e._v("fee_rate")]),e._v(' column is the output we want, also called the "'),t("em",[e._v("target")]),e._v('" or "'),t("em",[e._v("label")]),e._v('" in ML terminology, and the other columns are our inputs.')]),e._v(" "),t("p",[e._v("Can we build this table just by looking at the Bitcoin blockchain? Unfortunately, we can't:\nThe main thing that's missing is an indication of when the node first saw a transaction that has been later confirmed in a block. With that knowledge we can say that the fee rate of that transaction was the exact value required to confirm\nwithin the number of blocks it actually took to be confirmed. For instance, if we see transaction "),t("code",[e._v("t")]),e._v(" when the blockchain is at height "),t("code",[e._v("1000")]),e._v(" and then we notice that "),t("code",[e._v("t")]),e._v(" has been included in block "),t("code",[e._v("1006")]),e._v(", we can deduce that the\nfee rate paid by "),t("code",[e._v("t")]),e._v(" was the exact value required to get confirmed within the next "),t("code",[e._v("6")]),e._v(" blocks.")]),e._v(" "),t("p",[e._v("So to build our model, we first need to gather these data, and machine learning needs a "),t("em",[e._v("lot")]),e._v(" of data to work well.")]),e._v(" "),t("h4",{attrs:{id:"the-data-logger"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-data-logger"}},[e._v("#")]),e._v(" The data logger")]),e._v(" "),t("p",[e._v("The "),t("a",{attrs:{href:"https://github.com/RCasatta/bitcoin_logger",target:"_blank",rel:"noopener noreferrer"}},[e._v("data logger"),t("OutboundLink")],1),e._v(" is built with the purpose of collecting all the data we need, and it's MIT licensed open source software written in Rust.")]),e._v(" "),t("p",[e._v("We need to register the moment in time when transactions enter in the node's mempool; to be efficient and precise we should not only call the RPC endpoints but listen to "),t("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/zmq.md",target:"_blank",rel:"noopener noreferrer"}},[e._v("ZMQ"),t("OutboundLink")],1),e._v(" events. Luckily, the just released bitcoin core 0.21.0 added a new "),t("a",{attrs:{href:"https://github.com/bitcoin/bitcoin/blob/master/doc/zmq.md",target:"_blank",rel:"noopener noreferrer"}},[e._v("ZMQ"),t("OutboundLink")],1),e._v(" topic "),t("code",[e._v("zmqpubsequence")]),e._v(" notifying mempool events (and block events). The logger is also listening to "),t("code",[e._v("zmqpubrawtx")]),e._v(" and "),t("code",[e._v("zmqpubrawblock")]),e._v(" topics, to make less RPC calls.")]),e._v(" "),t("p",[e._v("We are not only interested in the timestamp of the transaction entering the mempool, but also how many blocks it will take until the same transaction is confirmed.\nIn the final dataset this field is called "),t("code",[e._v("confirms_in")]),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn4",id:"fnref4"}},[e._v("[4]")])]),e._v("; if "),t("code",[e._v("confirms_in = 1")]),e._v(" it means the transaction is confirmed in the first block created after it has been seen for the first time.")]),e._v(" "),t("p",[e._v("Another critical piece of information logged by the data logger is the "),t("code",[e._v("fee_rate")]),e._v(" of the transaction, since the absolute fee value paid by a bitcoin transaction is not available nor derivable given only the transaction itself, as the inputs don't have explicit amounts.")]),e._v(" "),t("p",[e._v("All these data (apart from the time of the transaction entering in the mempool) can actually be reconstructed simply by looking at the blockchain. However, querying the bitcoin node can be fairly slow, and during the model training iterations we want to recreate the ML dataset rapidly"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn5",id:"fnref5"}},[e._v("[5]")])]),e._v(", for example whenever we need to modify or add a new field.")]),e._v(" "),t("p",[e._v("For these reasons, the logger is split into two parts: a process listening to the events sent by our node, which creates raw logs, and then a second process that uses these logs to create the final CSV dataset.\nRaw logs are self-contained: for example, they contain all the previous transaction output values for every relevant transaction. This causes some redundancy, but in this case it's better to trade some efficiency for more performance\nwhen recreating the dataset.")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/high-level-graph.svg",alt:"High level graph"}})]),e._v(" "),t("p",[e._v("My logger instance started collecting data on the 18th of December 2020, and as of today (25th January 2020), the raw logs are about 16GB.")]),e._v(" "),t("p",[e._v("I expect (or at least hope) the raw logs, the CSV dataset, or the data logger will be useful also for other projects as well, like monitoring the propagation of transactions or other works involving raw mempool data. We will share raw logs data through torrent soon.")]),e._v(" "),t("p",[e._v("In the following "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-2/"}},[e._v("Part 2")]),e._v(" we are going to talk about the dataset.")],1),e._v(" "),t("hr",{staticClass:"footnotes-sep"}),e._v(" "),t("section",{staticClass:"footnotes"},[t("ol",{staticClass:"footnotes-list"},[t("li",{staticClass:"footnote-item",attrs:{id:"fn1"}},[t("p",[e._v("The transaction fee rate is the ratio between the absolute fee expressed in satoshi, over the weight of the transaction measured in virtual bytes. The weight of the transaction is similar to the byte size, however a part of the transaction (the segwit part) is discounted, their byte size is considered less because it creates less burden for the network. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref1"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn2"}},[t("p",[e._v("mempool is the set of transactions that are valid by consensus rules (for example, they are spending existing bitcoin), broadcasted in the bitcoin peer to peer network, but they are not yet part of the blockchain. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref2"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn3"}},[t("p",[e._v("DISCLAIMER: I am not an expert data-scientist! "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref3"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn4"}},[t("p",[e._v("Conceptually similar to bitcoin core "),t("code",[e._v("estimatesmartfee")]),e._v(' parameter called "blocks target", however, '),t("code",[e._v("confirms_in")]),e._v(" is the real value not the desired target. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref4"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn5"}},[t("p",[e._v("16GB of compressed raw logs are processed and a compressed CSV produced in about 5 minutes. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref5"}},[e._v("↩︎")])])])])])])}),[],!1,null,null,null);t.default=n.exports}}]); \ No newline at end of file diff --git a/assets/js/23.dda94059.js b/assets/js/23.ec6da89d.js similarity index 99% rename from assets/js/23.dda94059.js rename to assets/js/23.ec6da89d.js index d0a6d21c2f..c366da12d7 100644 --- a/assets/js/23.dda94059.js +++ b/assets/js/23.ec6da89d.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[23],{369:function(e,t,a){"use strict";a.r(t);var o=a(7),n=Object(o.a)({},(function(){var e=this,t=e._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This post is part 2 of 3 of a series. ("),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-1/"}},[e._v("Part 1")]),e._v(", "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-3/"}},[e._v("Part 3")]),e._v(")")],1),e._v(" "),t("ul",[t("li",[t("a",{attrs:{href:"#the-dataset"}},[e._v("The dataset")]),e._v(" "),t("ul",[t("li",[t("a",{attrs:{href:"#the-mempool"}},[e._v("The mempool")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#the-outliers"}},[e._v("The outliers")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#recap"}},[e._v("Recap")])])])])]),e._v(" "),t("h2",{attrs:{id:"the-dataset"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-dataset"}},[e._v("#")]),e._v(" The dataset")]),e._v(" "),t("p",[e._v("The "),t("a",{attrs:{href:"https://storage.googleapis.com/bitcoin_log/dataset_18.csv.gz",target:"_blank",rel:"noopener noreferrer"}},[e._v("dataset"),t("OutboundLink")],1),e._v(" is publicly available (~500MB gzip compressed, ~2GB as plain CSV).")]),e._v(" "),t("p",[e._v("The output of the model is the fee rate, expressed in "),t("code",[e._v("[satoshi/vbytes]")]),e._v(".")]),e._v(" "),t("p",[e._v("What about the inputs? Generally speaking, we have two main requirements for what can be included as input for our model:")]),e._v(" "),t("ul",[t("li",[e._v("It must be correlated to the output, even with a non-linear relation.")]),e._v(" "),t("li",[e._v("It must be available to a light client: for instance, assuming to have knowledge and an index of the last 1000 blocks is considered too much.")])]),e._v(" "),t("p",[e._v("To evaluate the approach we are taking, we also want to compare our model's results with another available estimation: for this reason the dataset includes data to compute the error agains Bitcoin Core's "),t("code",[e._v("estimatesmartfee")]),e._v(" results, even though we are not going to use it for this model.")]),e._v(" "),t("p",[e._v("The dataset will contain only transactions that spend already confirmed inputs. If we wanted to include transactions with unconfirmed inputs as well, the fee rate would have to be computed as a whole;\nfor example if transaction "),t("code",[e._v("t2")]),e._v(" spends an unconfirmed input from "),t("code",[e._v("t1")]),e._v(" (while "),t("code",[e._v("t1")]),e._v(" only spends confirmed inputs, and all its other outputs are unspent), the aggregated fee rate would have to be used.\nSupposing "),t("code",[e._v("f()")]),e._v(" is extracts the absolute fee and "),t("code",[e._v("w()")]),e._v(" the transaction weight, the aggregated fee rate would be "),t("code",[e._v("(f(t1) + f(t2)) / (w(t1) + w(t2))")]),e._v(". Thus, as already said previously, to keep things simple the model simply discards all the transaction\nthat would need to perform this computation.")]),e._v(" "),t("p",[e._v("For the same reason the dataset has the "),t("code",[e._v("parent_in_cpfp")]),e._v(" flag. When a transaction has inputs confirmed (so it's not excluded by the previous rule) but one or more of its output have been spent by a transaction confirmed in the same block, "),t("code",[e._v("parent_in_cpfp")]),e._v(" is "),t("code",[e._v("1")]),e._v(".\nTransactions with "),t("code",[e._v("parent_in_cpfp = 1")]),e._v(" are included in the dataset but excluded by the current model, since the miner probably considered an aggregated fee rate while picking the transactions to build a block.")]),e._v(" "),t("h4",{attrs:{id:"the-mempool"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-mempool"}},[e._v("#")]),e._v(" The mempool")]),e._v(" "),t("p",[e._v("The most important input of our model is the current "),t("em",[e._v("status")]),e._v(' of the mempool itself. However, we cannot feed the model with a list of the fee rate of every unconfirmed transaction, because this array would have a variable length.\nTo overcome this, the transaction contained in the mempool are grouped in "buckets" which are basically subsets of the mempool where all the transactions contained in a bucket have a similar fee rate. In particular we only care about the\n'),t("em",[e._v("number")]),e._v(" of transaction in every "),t("em",[e._v("bucket")]),e._v(", not which transactions it contains.")]),e._v(" "),t("p",[e._v("The mempool buckets array is defined by two parameters, the "),t("code",[e._v("percentage_increment")]),e._v(" and the "),t("code",[e._v("array_max")]),e._v(" value.\nStarting from the minimum fee rate value "),t("code",[e._v("min_relay_fee=1.0")]),e._v(", the "),t("code",[e._v("ith")]),e._v(" element is: "),t("code",[e._v("a_i=min_relay_fee * (1+percentage_increment)^(i+1)")])]),e._v(" "),t("p",[e._v("For instance, choosing the mempool buckets array to have parameters "),t("code",[e._v("percentage_increment = 50%")]),e._v(" and "),t("code",[e._v("array_max = 500.0 sat/vbytes")]),e._v(" the buckets would be constructed like so:")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("bucket")]),e._v(" "),t("th",[e._v("bucket min fee rate")]),e._v(" "),t("th",[e._v("bucket max fee rate")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("a_0")]),e._v(" "),t("td",[e._v("1.0")]),e._v(" "),t("td",[e._v("1.5")])]),e._v(" "),t("tr",[t("td",[e._v("a_1")]),e._v(" "),t("td",[e._v("1.5")]),e._v(" "),t("td",[e._v("2.25")])]),e._v(" "),t("tr",[t("td",[e._v("a_2")]),e._v(" "),t("td",[e._v("2.25")]),e._v(" "),t("td",[e._v("3.375")])]),e._v(" "),t("tr",[t("td",[e._v("a_15")]),e._v(" "),t("td",[e._v("437.89")]),e._v(" "),t("td",[e._v("inf")])])])]),e._v(" "),t("p",[e._v("The array stops at "),t("code",[e._v("a15")]),e._v(" because "),t("code",[e._v("a16")]),e._v(" would have a bucket min greater than "),t("code",[e._v("array_max")]),e._v(".")]),e._v(" "),t("p",[e._v("The model is for light-client such as "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[e._v("neutrino"),t("OutboundLink")],1),e._v(" based ones. In these clients the mempool is already available (it's needed to check for received transactions) but we can't compute fee rates of this transactions because previous confirmed inputs are not in the mempool!")]),e._v(" "),t("p",[e._v("Luckily, "),t("strong",[e._v("thanks to temporal locality "),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn1",id:"fnref1"}},[e._v("[1]")])]),e._v(", an important part of mempool transactions spend outputs created very recently")]),e._v(", for example in the last 6 blocks.\nThe blocks are available through the p2p network, and downloading the last 6 is considered a good compromise between resource consumption and accurate prediction. We need the model to be built with the same data available in the prediction phase, as a consequence "),t("em",[e._v("the mempool data in the dataset refers only to transactions having their inputs in the last 6 blocks")]),e._v(". However the "),t("code",[e._v("bitcoin-csv")]),e._v(" tool inside the "),t("a",{attrs:{href:"https://github.com/RCasatta/bitcoin_logger",target:"_blank",rel:"noopener noreferrer"}},[e._v("data logger"),t("OutboundLink")],1),e._v(" allows to configure this parameter.")]),e._v(" "),t("h4",{attrs:{id:"the-outliers"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-outliers"}},[e._v("#")]),e._v(" The outliers")]),e._v(" "),t("p",[e._v("The dataset also contains the block percentile fee rate "),t("code",[e._v("q_k")]),e._v(", considering "),t("code",[e._v("r_i")]),e._v(" to be the rate of the "),t("code",[e._v("ith")]),e._v(" transaction in a block, "),t("code",[e._v("q_k")]),e._v(" is the fee rate value such that for each transaction in a block "),t("code",[e._v("r_i")]),e._v(" < "),t("code",[e._v("q_k")]),e._v(" returns the "),t("code",[e._v("k%")]),e._v(" transactions in the block that are paying lower fees.")]),e._v(" "),t("p",[e._v("Percentiles are not used to feed the model but to filter some outliers tx.\nRemoving this observations is controversial at best and considered cheating at worse. However, it should be considered that Bitcoin Core "),t("code",[e._v("estimatesmartfee")]),e._v(" doesn't even bother to give estimation for the next block, we think this is due to the fact that many transactions that are confirming in the next block are huge overestimation, or clearly errors like "),t("a",{attrs:{href:"https://blockstream.info/tx/33291156ab79e9b4a1019b618b0acfa18cbdf8fa6b71c43a9eed62a849b86f9a",target:"_blank",rel:"noopener noreferrer"}},[e._v("this one"),t("OutboundLink")],1),e._v(" we found when we started logging data.\nThese outliers are several for transactions confirming in the next block ("),t("code",[e._v("confirms_in=1")]),e._v("), less so for "),t("code",[e._v("confirms_in=2")]),e._v(", mostly disappeared for "),t("code",[e._v("confirms_in=3")]),e._v(" or more. It's counterintuitive that overestimation exists for "),t("code",[e._v("confirms_in>1")]),e._v(", by definition an overestimation is a fee rate way higher than needed, so how is possible that an overestimation doesn't enter the very next block? There are a couple of reasons why a block is discovered without containing a transaction with high fee rate:")]),e._v(" "),t("ul",[t("li",[e._v("network latency: my node saw the transaction but the miner didn't see that transaction yet,")]),e._v(" "),t("li",[e._v("block building latency: the miner saw the transaction, but didn't finish to rebuild the block template or decided it's more efficient to finish a cycle on the older block template.")])]),e._v(" "),t("p",[e._v("To keep the model balanced, when overestimation is filtered out, underestimation are filtered out as well. This also has the effect to remove some of the transactions possibly included because a fee is payed out-of-band.\nAnother reason to filter transactions is that the dataset is over-represented by transactions with low "),t("code",[e._v("confirms_in")]),e._v(": more than 50% of transactions get confirmed in the next block, so we think it's good to filter some of these transactions.")]),e._v(" "),t("p",[e._v("The applied filters are the following:")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("confirms_in")]),e._v(" "),t("th",[e._v("lower")]),e._v(" "),t("th",[e._v("higher")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("1")]),e._v(" "),t("td",[e._v("q45")]),e._v(" "),t("td",[e._v("q55")])]),e._v(" "),t("tr",[t("td",[e._v("2")]),e._v(" "),t("td",[e._v("q30")]),e._v(" "),t("td",[e._v("q70")])]),e._v(" "),t("tr",[t("td",[e._v("3")]),e._v(" "),t("td",[e._v("q1")]),e._v(" "),t("td",[e._v("q99")])])])]),e._v(" "),t("p",[e._v("Not yet convinced by the removal of these outliers? The "),t("a",{attrs:{href:"https://storage.googleapis.com/bitcoin_log/dataset_18.csv.gz",target:"_blank",rel:"noopener noreferrer"}},[e._v("dataset"),t("OutboundLink")],1),e._v(" contains all the observations, make your model 😃")]),e._v(" "),t("h4",{attrs:{id:"recap"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#recap"}},[e._v("#")]),e._v(" Recap")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("column")]),e._v(" "),t("th",[e._v("used in the model")]),e._v(" "),t("th",[e._v("description")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("txid")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Transaction hash, useful for debugging")])]),e._v(" "),t("tr",[t("td",[e._v("timestamp")]),e._v(" "),t("td",[e._v("converted")]),e._v(" "),t("td",[e._v("The time when the transaction has been added in the mempool, in the model is used in the form "),t("code",[e._v("day_of_week")]),e._v(" and "),t("code",[e._v("hour")])])]),e._v(" "),t("tr",[t("td",[e._v("current_height")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("The blockchain height seen by the node in this moment")])]),e._v(" "),t("tr",[t("td",[e._v("confirms_in")]),e._v(" "),t("td",[e._v("yes")]),e._v(" "),t("td",[e._v("This transaction confirmed at block height "),t("code",[e._v("current_height+confirms_in")])])]),e._v(" "),t("tr",[t("td",[e._v("fee_rate")]),e._v(" "),t("td",[e._v("target")]),e._v(" "),t("td",[e._v("This transaction fee rate measured in "),t("code",[e._v("[sat/vbytes]")])])]),e._v(" "),t("tr",[t("td",[e._v("fee_rate_bytes")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("fee rate in satoshi / bytes, used to check Bitcoin Core "),t("code",[e._v("estimatesmartfee")]),e._v(" predictions")])]),e._v(" "),t("tr",[t("td",[e._v("block_avg_fee")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("block average fee rate "),t("code",[e._v("[sat/vbytes]")]),e._v(" of block "),t("code",[e._v("current_height+confirms_in")])])]),e._v(" "),t("tr",[t("td",[e._v("core_econ")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("bitcoin "),t("code",[e._v("estimatesmartfee")]),e._v(" result for "),t("code",[e._v("confirms_in")]),e._v(" block target and in economic mode. Could be not available "),t("code",[e._v("?")]),e._v(" when a block is connected more recently than the estimation has been requested, estimation are requested every 10 secs.")])]),e._v(" "),t("tr",[t("td",[e._v("core_cons")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Same as above but with conservative mode")])]),e._v(" "),t("tr",[t("td",[e._v("mempool_len")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Sum of the mempool transactions with fee rate available (sum of every "),t("code",[e._v("a*")]),e._v(" field)")])]),e._v(" "),t("tr",[t("td",[e._v("parent_in_cpfp")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("It's 1 when the transaction has outputs that are spent in the same block in which the transaction is confirmed (they are parent in a CPFP relations).")])]),e._v(" "),t("tr",[t("td",[e._v("q1-q30-...")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Transaction confirming fast could be outliers, usually paying a lot more than required, this percentiles are used to filter those transactions,")])]),e._v(" "),t("tr",[t("td",[e._v("a1-a2-...")]),e._v(" "),t("td",[e._v("yes")]),e._v(" "),t("td",[e._v("Contains the number of transaction in the mempool with known fee rate in the ith bucket.")])])])]),e._v(" "),t("p",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/the-good-the-bad-the-ugly.jpg",alt:"The good, the bad and the ugly"}})]),t("div",{attrs:{align:"center"}},[e._v('My biological neural network fired this, I think it\'s because a lot of chapters start with "The"')]),e._v(" "),t("br"),t("br"),t("p"),e._v(" "),t("p",[e._v("In the previous "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-1/"}},[e._v("Part 1")]),e._v(" we talked about the problem.")],1),e._v(" "),t("p",[e._v("In the following "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-3/"}},[e._v("Part 3")]),e._v(" we are going to talk about the model.")],1),e._v(" "),t("hr",{staticClass:"footnotes-sep"}),e._v(" "),t("section",{staticClass:"footnotes"},[t("ol",{staticClass:"footnotes-list"},[t("li",{staticClass:"footnote-item",attrs:{id:"fn1"}},[t("p",[e._v("In computer science temporal locality refers to the tendency to access recent data more often than older data. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref1"}},[e._v("↩︎")])])])])])])}),[],!1,null,null,null);t.default=n.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[23],{368:function(e,t,a){"use strict";a.r(t);var o=a(7),n=Object(o.a)({},(function(){var e=this,t=e._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This post is part 2 of 3 of a series. 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Generally speaking, we have two main requirements for what can be included as input for our model:")]),e._v(" "),t("ul",[t("li",[e._v("It must be correlated to the output, even with a non-linear relation.")]),e._v(" "),t("li",[e._v("It must be available to a light client: for instance, assuming to have knowledge and an index of the last 1000 blocks is considered too much.")])]),e._v(" "),t("p",[e._v("To evaluate the approach we are taking, we also want to compare our model's results with another available estimation: for this reason the dataset includes data to compute the error agains Bitcoin Core's "),t("code",[e._v("estimatesmartfee")]),e._v(" results, even though we are not going to use it for this model.")]),e._v(" "),t("p",[e._v("The dataset will contain only transactions that spend already confirmed inputs. If we wanted to include transactions with unconfirmed inputs as well, the fee rate would have to be computed as a whole;\nfor example if transaction "),t("code",[e._v("t2")]),e._v(" spends an unconfirmed input from "),t("code",[e._v("t1")]),e._v(" (while "),t("code",[e._v("t1")]),e._v(" only spends confirmed inputs, and all its other outputs are unspent), the aggregated fee rate would have to be used.\nSupposing "),t("code",[e._v("f()")]),e._v(" is extracts the absolute fee and "),t("code",[e._v("w()")]),e._v(" the transaction weight, the aggregated fee rate would be "),t("code",[e._v("(f(t1) + f(t2)) / (w(t1) + w(t2))")]),e._v(". Thus, as already said previously, to keep things simple the model simply discards all the transaction\nthat would need to perform this computation.")]),e._v(" "),t("p",[e._v("For the same reason the dataset has the "),t("code",[e._v("parent_in_cpfp")]),e._v(" flag. When a transaction has inputs confirmed (so it's not excluded by the previous rule) but one or more of its output have been spent by a transaction confirmed in the same block, "),t("code",[e._v("parent_in_cpfp")]),e._v(" is "),t("code",[e._v("1")]),e._v(".\nTransactions with "),t("code",[e._v("parent_in_cpfp = 1")]),e._v(" are included in the dataset but excluded by the current model, since the miner probably considered an aggregated fee rate while picking the transactions to build a block.")]),e._v(" "),t("h4",{attrs:{id:"the-mempool"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-mempool"}},[e._v("#")]),e._v(" The mempool")]),e._v(" "),t("p",[e._v("The most important input of our model is the current "),t("em",[e._v("status")]),e._v(' of the mempool itself. However, we cannot feed the model with a list of the fee rate of every unconfirmed transaction, because this array would have a variable length.\nTo overcome this, the transaction contained in the mempool are grouped in "buckets" which are basically subsets of the mempool where all the transactions contained in a bucket have a similar fee rate. In particular we only care about the\n'),t("em",[e._v("number")]),e._v(" of transaction in every "),t("em",[e._v("bucket")]),e._v(", not which transactions it contains.")]),e._v(" "),t("p",[e._v("The mempool buckets array is defined by two parameters, the "),t("code",[e._v("percentage_increment")]),e._v(" and the "),t("code",[e._v("array_max")]),e._v(" value.\nStarting from the minimum fee rate value "),t("code",[e._v("min_relay_fee=1.0")]),e._v(", the "),t("code",[e._v("ith")]),e._v(" element is: "),t("code",[e._v("a_i=min_relay_fee * (1+percentage_increment)^(i+1)")])]),e._v(" "),t("p",[e._v("For instance, choosing the mempool buckets array to have parameters "),t("code",[e._v("percentage_increment = 50%")]),e._v(" and "),t("code",[e._v("array_max = 500.0 sat/vbytes")]),e._v(" the buckets would be constructed like so:")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("bucket")]),e._v(" "),t("th",[e._v("bucket min fee rate")]),e._v(" "),t("th",[e._v("bucket max fee rate")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("a_0")]),e._v(" "),t("td",[e._v("1.0")]),e._v(" "),t("td",[e._v("1.5")])]),e._v(" "),t("tr",[t("td",[e._v("a_1")]),e._v(" "),t("td",[e._v("1.5")]),e._v(" "),t("td",[e._v("2.25")])]),e._v(" "),t("tr",[t("td",[e._v("a_2")]),e._v(" "),t("td",[e._v("2.25")]),e._v(" "),t("td",[e._v("3.375")])]),e._v(" "),t("tr",[t("td",[e._v("a_15")]),e._v(" "),t("td",[e._v("437.89")]),e._v(" "),t("td",[e._v("inf")])])])]),e._v(" "),t("p",[e._v("The array stops at "),t("code",[e._v("a15")]),e._v(" because "),t("code",[e._v("a16")]),e._v(" would have a bucket min greater than "),t("code",[e._v("array_max")]),e._v(".")]),e._v(" "),t("p",[e._v("The model is for light-client such as "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[e._v("neutrino"),t("OutboundLink")],1),e._v(" based ones. In these clients the mempool is already available (it's needed to check for received transactions) but we can't compute fee rates of this transactions because previous confirmed inputs are not in the mempool!")]),e._v(" "),t("p",[e._v("Luckily, "),t("strong",[e._v("thanks to temporal locality "),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn1",id:"fnref1"}},[e._v("[1]")])]),e._v(", an important part of mempool transactions spend outputs created very recently")]),e._v(", for example in the last 6 blocks.\nThe blocks are available through the p2p network, and downloading the last 6 is considered a good compromise between resource consumption and accurate prediction. We need the model to be built with the same data available in the prediction phase, as a consequence "),t("em",[e._v("the mempool data in the dataset refers only to transactions having their inputs in the last 6 blocks")]),e._v(". However the "),t("code",[e._v("bitcoin-csv")]),e._v(" tool inside the "),t("a",{attrs:{href:"https://github.com/RCasatta/bitcoin_logger",target:"_blank",rel:"noopener noreferrer"}},[e._v("data logger"),t("OutboundLink")],1),e._v(" allows to configure this parameter.")]),e._v(" "),t("h4",{attrs:{id:"the-outliers"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-outliers"}},[e._v("#")]),e._v(" The outliers")]),e._v(" "),t("p",[e._v("The dataset also contains the block percentile fee rate "),t("code",[e._v("q_k")]),e._v(", considering "),t("code",[e._v("r_i")]),e._v(" to be the rate of the "),t("code",[e._v("ith")]),e._v(" transaction in a block, "),t("code",[e._v("q_k")]),e._v(" is the fee rate value such that for each transaction in a block "),t("code",[e._v("r_i")]),e._v(" < "),t("code",[e._v("q_k")]),e._v(" returns the "),t("code",[e._v("k%")]),e._v(" transactions in the block that are paying lower fees.")]),e._v(" "),t("p",[e._v("Percentiles are not used to feed the model but to filter some outliers tx.\nRemoving this observations is controversial at best and considered cheating at worse. However, it should be considered that Bitcoin Core "),t("code",[e._v("estimatesmartfee")]),e._v(" doesn't even bother to give estimation for the next block, we think this is due to the fact that many transactions that are confirming in the next block are huge overestimation, or clearly errors like "),t("a",{attrs:{href:"https://blockstream.info/tx/33291156ab79e9b4a1019b618b0acfa18cbdf8fa6b71c43a9eed62a849b86f9a",target:"_blank",rel:"noopener noreferrer"}},[e._v("this one"),t("OutboundLink")],1),e._v(" we found when we started logging data.\nThese outliers are several for transactions confirming in the next block ("),t("code",[e._v("confirms_in=1")]),e._v("), less so for "),t("code",[e._v("confirms_in=2")]),e._v(", mostly disappeared for "),t("code",[e._v("confirms_in=3")]),e._v(" or more. It's counterintuitive that overestimation exists for "),t("code",[e._v("confirms_in>1")]),e._v(", by definition an overestimation is a fee rate way higher than needed, so how is possible that an overestimation doesn't enter the very next block? There are a couple of reasons why a block is discovered without containing a transaction with high fee rate:")]),e._v(" "),t("ul",[t("li",[e._v("network latency: my node saw the transaction but the miner didn't see that transaction yet,")]),e._v(" "),t("li",[e._v("block building latency: the miner saw the transaction, but didn't finish to rebuild the block template or decided it's more efficient to finish a cycle on the older block template.")])]),e._v(" "),t("p",[e._v("To keep the model balanced, when overestimation is filtered out, underestimation are filtered out as well. This also has the effect to remove some of the transactions possibly included because a fee is payed out-of-band.\nAnother reason to filter transactions is that the dataset is over-represented by transactions with low "),t("code",[e._v("confirms_in")]),e._v(": more than 50% of transactions get confirmed in the next block, so we think it's good to filter some of these transactions.")]),e._v(" "),t("p",[e._v("The applied filters are the following:")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("confirms_in")]),e._v(" "),t("th",[e._v("lower")]),e._v(" "),t("th",[e._v("higher")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("1")]),e._v(" "),t("td",[e._v("q45")]),e._v(" "),t("td",[e._v("q55")])]),e._v(" "),t("tr",[t("td",[e._v("2")]),e._v(" "),t("td",[e._v("q30")]),e._v(" "),t("td",[e._v("q70")])]),e._v(" "),t("tr",[t("td",[e._v("3")]),e._v(" "),t("td",[e._v("q1")]),e._v(" "),t("td",[e._v("q99")])])])]),e._v(" "),t("p",[e._v("Not yet convinced by the removal of these outliers? The "),t("a",{attrs:{href:"https://storage.googleapis.com/bitcoin_log/dataset_18.csv.gz",target:"_blank",rel:"noopener noreferrer"}},[e._v("dataset"),t("OutboundLink")],1),e._v(" contains all the observations, make your model 😃")]),e._v(" "),t("h4",{attrs:{id:"recap"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#recap"}},[e._v("#")]),e._v(" Recap")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("column")]),e._v(" "),t("th",[e._v("used in the model")]),e._v(" "),t("th",[e._v("description")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("txid")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Transaction hash, useful for debugging")])]),e._v(" "),t("tr",[t("td",[e._v("timestamp")]),e._v(" "),t("td",[e._v("converted")]),e._v(" "),t("td",[e._v("The time when the transaction has been added in the mempool, in the model is used in the form "),t("code",[e._v("day_of_week")]),e._v(" and "),t("code",[e._v("hour")])])]),e._v(" "),t("tr",[t("td",[e._v("current_height")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("The blockchain height seen by the node in this moment")])]),e._v(" "),t("tr",[t("td",[e._v("confirms_in")]),e._v(" "),t("td",[e._v("yes")]),e._v(" "),t("td",[e._v("This transaction confirmed at block height "),t("code",[e._v("current_height+confirms_in")])])]),e._v(" "),t("tr",[t("td",[e._v("fee_rate")]),e._v(" "),t("td",[e._v("target")]),e._v(" "),t("td",[e._v("This transaction fee rate measured in "),t("code",[e._v("[sat/vbytes]")])])]),e._v(" "),t("tr",[t("td",[e._v("fee_rate_bytes")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("fee rate in satoshi / bytes, used to check Bitcoin Core "),t("code",[e._v("estimatesmartfee")]),e._v(" predictions")])]),e._v(" "),t("tr",[t("td",[e._v("block_avg_fee")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("block average fee rate "),t("code",[e._v("[sat/vbytes]")]),e._v(" of block "),t("code",[e._v("current_height+confirms_in")])])]),e._v(" "),t("tr",[t("td",[e._v("core_econ")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("bitcoin "),t("code",[e._v("estimatesmartfee")]),e._v(" result for "),t("code",[e._v("confirms_in")]),e._v(" block target and in economic mode. Could be not available "),t("code",[e._v("?")]),e._v(" when a block is connected more recently than the estimation has been requested, estimation are requested every 10 secs.")])]),e._v(" "),t("tr",[t("td",[e._v("core_cons")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Same as above but with conservative mode")])]),e._v(" "),t("tr",[t("td",[e._v("mempool_len")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Sum of the mempool transactions with fee rate available (sum of every "),t("code",[e._v("a*")]),e._v(" field)")])]),e._v(" "),t("tr",[t("td",[e._v("parent_in_cpfp")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("It's 1 when the transaction has outputs that are spent in the same block in which the transaction is confirmed (they are parent in a CPFP relations).")])]),e._v(" "),t("tr",[t("td",[e._v("q1-q30-...")]),e._v(" "),t("td",[e._v("no")]),e._v(" "),t("td",[e._v("Transaction confirming fast could be outliers, usually paying a lot more than required, this percentiles are used to filter those transactions,")])]),e._v(" "),t("tr",[t("td",[e._v("a1-a2-...")]),e._v(" "),t("td",[e._v("yes")]),e._v(" "),t("td",[e._v("Contains the number of transaction in the mempool with known fee rate in the ith bucket.")])])])]),e._v(" "),t("p",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/the-good-the-bad-the-ugly.jpg",alt:"The good, the bad and the ugly"}})]),t("div",{attrs:{align:"center"}},[e._v('My biological neural network fired this, I think it\'s because a lot of chapters start with "The"')]),e._v(" "),t("br"),t("br"),t("p"),e._v(" "),t("p",[e._v("In the previous "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-1/"}},[e._v("Part 1")]),e._v(" we talked about the problem.")],1),e._v(" "),t("p",[e._v("In the following "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-3/"}},[e._v("Part 3")]),e._v(" we are going to talk about the model.")],1),e._v(" "),t("hr",{staticClass:"footnotes-sep"}),e._v(" "),t("section",{staticClass:"footnotes"},[t("ol",{staticClass:"footnotes-list"},[t("li",{staticClass:"footnote-item",attrs:{id:"fn1"}},[t("p",[e._v("In computer science temporal locality refers to the tendency to access recent data more often than older data. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref1"}},[e._v("↩︎")])])])])])])}),[],!1,null,null,null);t.default=n.exports}}]); \ No newline at end of file diff --git a/assets/js/24.bf504d89.js b/assets/js/24.a58c5c87.js similarity index 99% rename from assets/js/24.bf504d89.js rename to assets/js/24.a58c5c87.js index dcd29ccc97..ec72c9e014 100644 --- a/assets/js/24.bf504d89.js +++ b/assets/js/24.a58c5c87.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[24],{370:function(e,t,a){"use strict";a.r(t);var n=a(7),s=Object(n.a)({},(function(){var e=this,t=e._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This post is part 3 of 3 of a series. ("),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-1/"}},[e._v("Part 1")]),e._v(", "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-2/"}},[e._v("Part 2")]),e._v(")")],1),e._v(" "),t("ul",[t("li",[t("a",{attrs:{href:"#the-model"}},[e._v("The model")]),e._v(" "),t("ul",[t("li",[t("a",{attrs:{href:"#splitting"}},[e._v("Splitting")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#preprocessing"}},[e._v("Preprocessing")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#build"}},[e._v("Build")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#finally--training"}},[e._v("Finally, training")])])])]),e._v(" "),t("li",[t("a",{attrs:{href:"#the-prediction-phase"}},[e._v("The prediction phase")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#conclusion-and-future-development"}},[e._v("Conclusion and future development")])]),e._v(" "),t("li",[t("a",{attrs:{href:"#acknowledgements"}},[e._v("Acknowledgements")])])]),e._v(" "),t("h2",{attrs:{id:"the-model"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-model"}},[e._v("#")]),e._v(" The model")]),e._v(" "),t("p",[e._v("The code building and training the model with "),t("a",{attrs:{href:"https://www.tensorflow.org/",target:"_blank",rel:"noopener noreferrer"}},[e._v("tensorflow"),t("OutboundLink")],1),e._v(" is available in "),t("a",{attrs:{href:"https://colab.research.google.com/drive/1yamwh8nE4NhmGButep-pfUT-1uRKs49a?usp=sharing",target:"_blank",rel:"noopener noreferrer"}},[e._v("google colab notebook"),t("OutboundLink")],1),e._v(" (jupyter notebook); you can also download the file as plain python and run it locally. At least 1 hour is needed to train the full model, but it heavily depends on the hardware available.")]),e._v(" "),t("p",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-confirms_in-fee_rate.png",alt:"graph confirm_in blocks vs fee_rate"}})]),t("div",{attrs:{align:"center"}},[e._v("Do you want to choose the fee without a model? In the last 5 weeks a ~50 sat/vbyte transaction never took more than a day to confirm and a ~10 sat/vbyte never took more than a week")]),t("br"),t("p"),e._v(" "),t("p",[e._v("As a reference, in the code we have a calculation of the bitcoin core "),t("code",[e._v("estimatesmartfee")]),e._v(" MAE"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn1",id:"fnref1"}},[e._v("[1]")])]),e._v(" and drift"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn2",id:"fnref2"}},[e._v("[2]")])]),e._v(".\nMAE is computed as "),t("code",[e._v("avg(abs(fee_rate - core_econ))")]),e._v(" when "),t("code",[e._v("core_econ")]),e._v(" is available (about 1.2M observations, sometime the value is not available when considered too old).")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("estimatesmartfee mode")]),e._v(" "),t("th",[e._v("MAE [satoshi/vbytes]")]),e._v(" "),t("th",[e._v("drift")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("economic")]),e._v(" "),t("td",[e._v("28.77")]),e._v(" "),t("td",[e._v("20.79")])]),e._v(" "),t("tr",[t("td",[e._v("conservative")]),e._v(" "),t("td",[e._v("46.49")]),e._v(" "),t("td",[e._v("44.73")])])])]),e._v(" "),t("p",[e._v("As seen from the table, the error is quite high, but the positive drift suggests "),t("code",[e._v("estimatesmartfee")]),e._v(" prefers to overestimate to avoid transactions not confirming.")]),e._v(" "),t("p",[e._v('As we said in the introduction, network traffic is correlated with time and we have the timestamp of when the transaction has been first seen, however a ML model doesn\'t like plain numbers too much, but it behaves better with "number that repeats", like categories, so we are converting the timestamp in '),t("code",[e._v("day_of_week")]),e._v(" a number from 0 to 6, and "),t("code",[e._v("hours")]),e._v(" a number from 0 to 24.")]),e._v(" "),t("h4",{attrs:{id:"splitting"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#splitting"}},[e._v("#")]),e._v(" Splitting")]),e._v(" "),t("p",[e._v("The dataset is splitted in training and test data with a 80/20 proportion. As the name suggest the training part is used to train the model, the test is composed of other observations to test if the model is good with observations that has never seen (proving the model can generalize, not just memorizing the answer).")]),e._v(" "),t("p",[e._v("During the training the data is splitted again in 80/20 for training and validation respectively, validation is basically testing during training.")]),e._v(" "),t("p",[e._v("During splitting, the dataset is converted from a pandas data frame to tensorflow dataset, decreasing training times.")]),e._v(" "),t("h4",{attrs:{id:"preprocessing"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#preprocessing"}},[e._v("#")]),e._v(" Preprocessing")]),e._v(" "),t("p",[e._v("The preprocessing phase is part of the model however it contains transformations without parameters trained by the model.\nThis transformations are useful because model trains better if data are in some format, and having this phase inside the model helps to avoid to prepare the data before feeding the model at prediction phase.")]),e._v(" "),t("p",[e._v("Our model performs 2 kind of preprocessing:")]),e._v(" "),t("ul",[t("li",[t("p",[e._v("Normalization: model trains faster if numerical features have mean 0 and standard deviation equal to 1, so this layer is built by computing the "),t("code",[e._v("mean")]),e._v(" and "),t("code",[e._v("std")]),e._v(" from the series of a feature before training, and the model is feed with "),t("code",[e._v("(feature - mean)/std")]),e._v(". 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Trainable parameters are values initialized randomly and changed during the training phase. The trainable parameters are "),t("code",[e._v("7,361")]),e._v(", this number comes from the following, every neuron has an associated bias and a weight for every element in the inputs, thus:")]),e._v(" "),t("div",{staticClass:"language-shell extra-class"},[t("pre",{pre:!0,attrs:{class:"language-shell"}},[t("code",[t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("48")]),e._v(" input_values_weights + "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("1")]),e._v(" bias"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" * "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" first_layer_neurons"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n+ "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" input_values_weights + "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("1")]),e._v(" bias"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" * "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" second layer neurons"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n+ "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" input values weights + "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("1")]),e._v(" bias"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n\n"),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("49")]),e._v("*64+65*64+65 "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("=")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("7361")]),e._v("\n")])])]),t("p",[e._v("Honestly, neural network parameters are mostly the one taken from this tensorflow "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/regression",target:"_blank",rel:"noopener noreferrer"}},[e._v("example"),t("OutboundLink")],1),e._v(", we even tried to "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/keras_tuner",target:"_blank",rel:"noopener noreferrer"}},[e._v("tune hyperparameters"),t("OutboundLink")],1),e._v(", however, we decided to follow this "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/overfit_and_underfit#demonstrate_overfitting",target:"_blank",rel:"noopener noreferrer"}},[e._v("advice"),t("OutboundLink")],1),e._v(": "),t("em",[e._v('"The simplest way to prevent overfitting is to start with a small model:"')]),e._v(". We hope this work will attract other data scientists to this bitcoin problem, improving the model. We also think that a longer time for the data collection is needed to capture various situations.")]),e._v(" "),t("p",[e._v("A significant part of a ML model are the activation functions, "),t("code",[e._v("relu")]),e._v(" (Rectified Linear Unit) is one of the most used lately, because it's simple and works well as we learned in this "),t("a",{attrs:{href:"https://youtu.be/aircAruvnKk?t=1035",target:"_blank",rel:"noopener noreferrer"}},[e._v("introducing neural network video"),t("OutboundLink")],1),e._v(". "),t("code",[e._v("relu")]),e._v(" it's equal to zero for negative values and equal to the input for positive values. Being non-linear allows the whole model to be non-linear.")]),e._v(" "),t("p",[e._v("For the last layer it is different: we want to enforce a minimum for the output, which is the minimum relay fee "),t("code",[e._v("1.0")]),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn3",id:"fnref3"}},[e._v("[3]")])]),e._v(". One could not simply cut the output of the model after prediction because all the training would not consider this constraint. So we need to build a custom activation function that the model training will be able to use for the "),t("a",{attrs:{href:"https://en.wikipedia.org/wiki/Gradient_descent#:~:text=Gradient%20descent%20is%20a%20first,the%20direction%20of%20steepest%20descent.",target:"_blank",rel:"noopener noreferrer"}},[e._v("gradient descent"),t("OutboundLink")],1),e._v(" optimization step. Luckily this is very simple using tensorflow primitives:")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("def clip(x):\n min = tf.constant(1.0)\n return tf.where(tf.less(x, min), min, x)\n")])])]),t("p",[e._v("Another important part is the optimizer, when we first read the aforementioned "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/regression",target:"_blank",rel:"noopener noreferrer"}},[e._v("example"),t("OutboundLink")],1),e._v(" the optimizer used was "),t("code",[e._v("RMSProp")]),e._v(" however the example updated lately and we noticed the optimizer changed in favor of "),t("code",[e._v("Adam")]),e._v(" which we read is the "),t("a",{attrs:{href:"https://towardsdatascience.com/adam-latest-trends-in-deep-learning-optimization-6be9a291375c",target:"_blank",rel:"noopener noreferrer"}},[e._v("latest trend"),t("OutboundLink")],1),e._v(" in data science. We changed the model to use "),t("code",[e._v("Adam")]),e._v(" and effectively the training is faster with "),t("code",[e._v("Adam")]),e._v(" and even slightly lower error is achieved.\nAnother important parameter is the learning rate, which we set to "),t("code",[e._v("0.01")]),e._v(" after manual trials; however there might be space for improvements such as using "),t("a",{attrs:{href:"https://www.tensorflow.org/api_docs/python/tf/compat/v1/train/exponential_decay",target:"_blank",rel:"noopener noreferrer"}},[e._v("exponential decay"),t("OutboundLink")],1),e._v(", starting with an high learning rate and decreasing it through training epochs.")]),e._v(" "),t("p",[e._v('The last part of the model configuration is the loss function: the objective of the training is to find the minimum of this function. Usually for regression problem (the ones having a number as output, not a category) the most used is the Mean squared error (MSE). MSE is measured as the average of squared difference between predictions and actual observations, giving larger penalties to large difference because of the square. An interesting property is that the bigger the error the faster the changes is good at the beginning of the training, while slowing down when the model predicts better is desirable to avoid "jumping out" the local minimum.')]),e._v(" "),t("h4",{attrs:{id:"finally-the-model-training"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#finally-the-model-training"}},[e._v("#")]),e._v(" Finally, the model training")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("PATIENCE = 20\nMAX_EPOCHS = 200\n\ndef train():\n early_stop = keras.callbacks.EarlyStopping(monitor='val_loss', patience=PATIENCE)\n history = model.fit(train_ds, epochs=MAX_EPOCHS, validation_data=val_ds, verbose=1, callbacks=[early_stop])\n return history\n\nhistory = train()\n")])])]),t("p",[e._v("This steps is the core of the neural network, it takes a while, let's analyze the output:")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("Epoch 1/200\n7559/7559 [==============================] - 34s 3ms/step - loss: 547.8023 - mae: 16.9547 - mse: 547.8023 - val_loss: 300.5965 - val_ma\ne: 11.9202 - val_mse: 300.5965\n...\nEpoch 158/200\n7559/7559 [==============================] - 31s 3ms/step - loss: 163.2548 - mae: 8.3126 - mse: 163.2548 - val_loss: 164.8296 - val_mae: 8.3402 - val_mse: 164.8296\n")])])]),t("p",[e._v("Training is done in epochs, under every epoch all the training data is iterated and model parameters updated to minimize the loss function.")]),e._v(" "),t("p",[e._v("The number "),t("code",[e._v("7559")]),e._v(" represent the number of steps. Theoretically the whole training data should be processed at once and parameters updated accordingly, however in practice this is infeasible for example for memory resource, thus the training happens in batch. In our case we have "),t("code",[e._v("1,934,999")]),e._v(" observations in the training set and our batch size is "),t("code",[e._v("256")]),e._v(", thus we have "),t("code",[e._v("1,437,841/256=7,558.58")]),e._v(" which by excess result in "),t("code",[e._v("7559")]),e._v(" steps.")]),e._v(" "),t("p",[e._v("The "),t("code",[e._v("~31s")]),e._v(" is the time it takes to process the epoch on a threadripper CPU but GPU or TPU could do better.")]),e._v(" "),t("p",[e._v("The value "),t("code",[e._v("loss")]),e._v(" is the MSE on the training data while "),t("code",[e._v("val_loss")]),e._v(" is the MSE value on the validation data. As far as we understand the separated validation data helps to detect the machine learning enemy, overfitting. Because in case of overfitting the value "),t("code",[e._v("loss")]),e._v(" continue to improve (almost indefinitely) while "),t("code",[e._v("val_loss")]),e._v(" start improving with the loss but a certain point diverge, indicating the network is memorizing the training data to improve "),t("code",[e._v("loss")]),e._v(" but in doing so losing generalizing capabilities.")]),e._v(" "),t("p",[e._v("Our model doesn't look to suffer overfitting cause "),t("code",[e._v("loss")]),e._v(" and "),t("code",[e._v("val_loss")]),e._v(" doesn't diverge during training")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-train-history.png",alt:"train history"}})]),e._v(" "),t("p",[e._v("While we told the training to do 200 epochs, the training stopped at 158 because we added an "),t("code",[e._v("early_stop")]),e._v(" call back with "),t("code",[e._v("20")]),e._v(" as "),t("code",[e._v("PATIENCE")]),e._v(", meaning that after 20 epoch and no improvement in "),t("code",[e._v("val_loss")]),e._v(" the training is halted, saving time and potentially avoiding overfitting.")]),e._v(" "),t("h2",{attrs:{id:"the-prediction-phase"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-prediction-phase"}},[e._v("#")]),e._v(" The prediction phase")]),e._v(" "),t("p",[e._v("A "),t("a",{attrs:{href:"https://github.com/RCasatta/estimate_ml_fee",target:"_blank",rel:"noopener noreferrer"}},[e._v("prediction test tool"),t("OutboundLink")],1),e._v(" is available on github. At the moment it uses a bitcoin core node to provide network data for simplicity, but it queries it only for the mempool and the last 6 blocks, so it's something that also a light-client could do"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn4",id:"fnref4"}},[e._v("[4]")])]),e._v(".")]),e._v(" "),t("p",[e._v("The following chart is probably the best visualization to evaluate the model, on the x axis there is the real fee rate while on the y axis there is the prediction, the more the points are centered on the bisection, the more the model is good.\nWe can see the model is doing quite well, the MAE is 8 which is way lower than "),t("code",[e._v("estimatesmartfee")]),e._v(". However, there are big errors some times, in particular for prediction for fast confirmation ("),t("code",[e._v("confirms_in=1 or confirms_in=2")]),e._v(") as shown by the orange points. Creating a model only for blocks target greater than 2 instead of simply remove some observations may be an option.")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-true-and-predictions.png",alt:"prediction results"}})]),e._v(" "),t("p",[e._v("The following chart is instead a distribution of the errors, which for good model should resemble the normal distribution centered in 0, and it loooks like the model is respecting that.")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-error-distribution.png",alt:"error distribution"}})]),e._v(" "),t("h2",{attrs:{id:"conclusion-and-future-development"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#conclusion-and-future-development"}},[e._v("#")]),e._v(" Conclusion and future development")]),e._v(" "),t("p",[e._v("The results have shown deep neural network are a tool capable of good bitcoin transaction fee estimations; this suggests that further ML research in this area might be promising.")]),e._v(" "),t("p",[e._v("This is just a starting point, there are many future improvements such as:")]),e._v(" "),t("ul",[t("li",[e._v("Build a separate model with full knowledge, thus for full, always-connected nodes could be interesting and improve network resource allocation with respect to current estimators.")]),e._v(" "),t("li",[e._v("Tensorflow is a huge dependency, and since it contains all the feature to build and train a model, most of the feature are not needed in the prediction phase. In fact tensorflow lite exists which is specifically created for embedded and mobile devices; the "),t("a",{attrs:{href:"https://github.com/RCasatta/estimate_ml_fee",target:"_blank",rel:"noopener noreferrer"}},[e._v("prediction test tool"),t("OutboundLink")],1),e._v(" and the final integration in "),t("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk",target:"_blank",rel:"noopener noreferrer"}},[e._v("bdk"),t("OutboundLink")],1),e._v(" should use it.")]),e._v(" "),t("li",[e._v("Explore other fields to improve model predictions such as:\n"),t("ul",[t("li",[e._v("A bucket array of the transactions in the last 6 blocks with known fee rates. This should in particular help estimations with almost empty mempool.")]),e._v(" "),t("li",[e._v("Transaction weight")]),e._v(" "),t("li",[e._v("Time from last block")])])]),e._v(" "),t("li",[e._v("Some fields are very important and could benefit from pre-processing expansion, for instance applying "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/structured_data/feature_columns#hashed_feature_columns",target:"_blank",rel:"noopener noreferrer"}},[e._v("hashed feature columns"),t("OutboundLink")],1),e._v(" to "),t("code",[e._v("confirms_in")]),e._v(".")]),e._v(" "),t("li",[e._v("Bitcoin logger could be improved by a merge command to unify raw logs files, reducing redundancy and consequently disk occupation.")]),e._v(" "),t("li",[e._v("The dataset could be created in multiple files to allow more parallelism and use less memory during training.")]),e._v(" "),t("li",[e._v("Saving the dataset in "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/load_data/tfrecord",target:"_blank",rel:"noopener noreferrer"}},[e._v("TFRecord format"),t("OutboundLink")],1),e._v(" instead of CSV")]),e._v(" "),t("li",[e._v("At the moment we are training the model on a threadripper CPU, training the code on GPU or even TPU will be needed to decrease training time, especially because input data will grow.")]),e._v(" "),t("li",[e._v("The "),t("a",{attrs:{href:"https://github.com/RCasatta/estimate_ml_fee",target:"_blank",rel:"noopener noreferrer"}},[e._v("prediction test tool"),t("OutboundLink")],1),e._v(" should estimate only using the p2p bitcoin network, without requiring a node. This work would be propedeutic for "),t("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk",target:"_blank",rel:"noopener noreferrer"}},[e._v("bdk"),t("OutboundLink")],1),e._v(" integration")]),e._v(" "),t("li",[e._v("At the moment mempool buckets are multiple inputs "),t("code",[e._v("a*")]),e._v(" as show in the model graph; since they are related, is it possible to merge them in one TensorArray?")]),e._v(" "),t("li",[e._v("Sometimes the model does not learn and "),t("a",{attrs:{href:"https://github.com/RCasatta/bitcoin_logger/blob/master/notes.md",target:"_blank",rel:"noopener noreferrer"}},[e._v("gets stuck"),t("OutboundLink")],1),e._v(". The reason is the "),t("code",[e._v("clip")]),e._v(" function applied in the last layer is constant for a value lower than 1. In this case, the derivative is 0 and the gradient descent doesn't know where to go. Instead of using the "),t("code",[e._v("clip")]),e._v(" function apply penalties to the loss function for values lower than 1.")]),e._v(" "),t("li",[e._v("There are issues regarding dead neurons (going to 0) or neurons with big weight, weight results should be monitored for this events, and also weight decay and L2 regularization should be explored.")]),e._v(" "),t("li",[e._v("Tune hyper-parameters technique should be re-tested.")]),e._v(" "),t("li",[e._v("Predictions should be monotonic decreasing for growing "),t("code",[e._v("confirms_in")]),e._v(" parameter; for obvious reason it doesn't make sense that an higher fee rate will result in a higher confirmation time. But since this is not enforced anywhere in the model, at the moment this could happen.")]),e._v(" "),t("li",[e._v("Since nodes with bloom filter disabled doesn't serve the mempool anymore, a model based only on last blocks should be evaluated.")])]),e._v(" "),t("h2",{attrs:{id:"acknowledgements"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#acknowledgements"}},[e._v("#")]),e._v(" Acknowledgements")]),e._v(" "),t("p",[e._v("Thanks to "),t("a",{attrs:{href:"https://squarecrypto.org/",target:"_blank",rel:"noopener noreferrer"}},[e._v("Square crypto"),t("OutboundLink")],1),e._v(" for sponsoring this work and thanks to the reviewers: "),t("a",{attrs:{href:"https://twitter.com/LeoComandini",target:"_blank",rel:"noopener noreferrer"}},[e._v("Leonardo Comandini"),t("OutboundLink")],1),e._v(", "),t("a",{attrs:{href:"https://twitter.com/domegabri",target:"_blank",rel:"noopener noreferrer"}},[e._v("Domenico Gabriele"),t("OutboundLink")],1),e._v(", "),t("a",{attrs:{href:"https://twitter.com/afilini",target:"_blank",rel:"noopener noreferrer"}},[e._v("Alekos Filini"),t("OutboundLink")],1),e._v(", "),t("a",{attrs:{href:"https://twitter.com/Ferdinando1970",target:"_blank",rel:"noopener noreferrer"}},[e._v("Ferdinando Ametrano"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("And also this tweet that remembered me "),t("a",{attrs:{href:"https://twitter.com/RCasatta",target:"_blank",rel:"noopener noreferrer"}},[e._v("I"),t("OutboundLink")],1),e._v(" had this work in my TODO list")]),e._v(" "),t("blockquote",{staticClass:"twitter-tweet"},[t("p",{attrs:{lang:"en",dir:"ltr"}},[e._v("I don't understand Machine Learning(ML), but is it horrible to use ML to predict bitcoin fees? "),t("br"),t("br"),e._v('I have heard tales of this "Deep Learning" thing where you throw a bunch of data at it and it gives you good results with high accuracy.')]),e._v("— sanket1729 (@sanket1729) "),t("a",{attrs:{href:"https://twitter.com/sanket1729/status/1336624662365822977?ref_src=twsrc%5Etfw"}},[e._v("December 9, 2020")])]),e._v(" "),t("script",{attrs:{async:"",src:"https://platform.twitter.com/widgets.js",charset:"utf-8"}}),e._v(" "),t("p",[e._v("This is the final part of the series. In the previous "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-1/"}},[e._v("Part 1")]),e._v(" we talked about the problem and in "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-2/"}},[e._v("Part 2")]),e._v(" we talked about the dataset.")],1),e._v(" "),t("hr",{staticClass:"footnotes-sep"}),e._v(" "),t("section",{staticClass:"footnotes"},[t("ol",{staticClass:"footnotes-list"},[t("li",{staticClass:"footnote-item",attrs:{id:"fn1"}},[t("p",[e._v("MAE is Mean Absolute Error, which is the average of the series built by the absolute difference between the real value and the estimation. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref1"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn2"}},[t("p",[e._v("drift like MAE, but without the absolute value "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref2"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn3"}},[t("p",[e._v("Most node won't relay transactions with fee lower than the min relay fee, which has a default of "),t("code",[e._v("1.0")]),e._v(" "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref3"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn4"}},[t("p",[e._v("An important issue emerged after the article came out, a bitcoin core client with bloom filter disabled (default as of 0.21) doesn't serve the mempool via p2p. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref4"}},[e._v("↩︎")])])])])])])}),[],!1,null,null,null);t.default=s.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[24],{369:function(e,t,a){"use strict";a.r(t);var n=a(7),s=Object(n.a)({},(function(){var e=this,t=e._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This post is part 3 of 3 of a series. 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At least 1 hour is needed to train the full model, but it heavily depends on the hardware available.")]),e._v(" "),t("p",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-confirms_in-fee_rate.png",alt:"graph confirm_in blocks vs fee_rate"}})]),t("div",{attrs:{align:"center"}},[e._v("Do you want to choose the fee without a model? In the last 5 weeks a ~50 sat/vbyte transaction never took more than a day to confirm and a ~10 sat/vbyte never took more than a week")]),t("br"),t("p"),e._v(" "),t("p",[e._v("As a reference, in the code we have a calculation of the bitcoin core "),t("code",[e._v("estimatesmartfee")]),e._v(" MAE"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn1",id:"fnref1"}},[e._v("[1]")])]),e._v(" and drift"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn2",id:"fnref2"}},[e._v("[2]")])]),e._v(".\nMAE is computed as "),t("code",[e._v("avg(abs(fee_rate - core_econ))")]),e._v(" when "),t("code",[e._v("core_econ")]),e._v(" is available (about 1.2M observations, sometime the value is not available when considered too old).")]),e._v(" "),t("table",[t("thead",[t("tr",[t("th",[e._v("estimatesmartfee mode")]),e._v(" "),t("th",[e._v("MAE [satoshi/vbytes]")]),e._v(" "),t("th",[e._v("drift")])])]),e._v(" "),t("tbody",[t("tr",[t("td",[e._v("economic")]),e._v(" "),t("td",[e._v("28.77")]),e._v(" "),t("td",[e._v("20.79")])]),e._v(" "),t("tr",[t("td",[e._v("conservative")]),e._v(" "),t("td",[e._v("46.49")]),e._v(" "),t("td",[e._v("44.73")])])])]),e._v(" "),t("p",[e._v("As seen from the table, the error is quite high, but the positive drift suggests "),t("code",[e._v("estimatesmartfee")]),e._v(" prefers to overestimate to avoid transactions not confirming.")]),e._v(" "),t("p",[e._v('As we said in the introduction, network traffic is correlated with time and we have the timestamp of when the transaction has been first seen, however a ML model doesn\'t like plain numbers too much, but it behaves better with "number that repeats", like categories, so we are converting the timestamp in '),t("code",[e._v("day_of_week")]),e._v(" a number from 0 to 6, and "),t("code",[e._v("hours")]),e._v(" a number from 0 to 24.")]),e._v(" "),t("h4",{attrs:{id:"splitting"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#splitting"}},[e._v("#")]),e._v(" Splitting")]),e._v(" "),t("p",[e._v("The dataset is splitted in training and test data with a 80/20 proportion. 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Trainable parameters are values initialized randomly and changed during the training phase. The trainable parameters are "),t("code",[e._v("7,361")]),e._v(", this number comes from the following, every neuron has an associated bias and a weight for every element in the inputs, thus:")]),e._v(" "),t("div",{staticClass:"language-shell extra-class"},[t("pre",{pre:!0,attrs:{class:"language-shell"}},[t("code",[t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("48")]),e._v(" input_values_weights + "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("1")]),e._v(" bias"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" * "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" first_layer_neurons"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n+ "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" input_values_weights + "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("1")]),e._v(" bias"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" * "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" second layer neurons"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n+ "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("64")]),e._v(" input values weights + "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("1")]),e._v(" bias"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n\n"),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("49")]),e._v("*64+65*64+65 "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("=")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[e._v("7361")]),e._v("\n")])])]),t("p",[e._v("Honestly, neural network parameters are mostly the one taken from this tensorflow "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/regression",target:"_blank",rel:"noopener noreferrer"}},[e._v("example"),t("OutboundLink")],1),e._v(", we even tried to "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/keras_tuner",target:"_blank",rel:"noopener noreferrer"}},[e._v("tune hyperparameters"),t("OutboundLink")],1),e._v(", however, we decided to follow this "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/overfit_and_underfit#demonstrate_overfitting",target:"_blank",rel:"noopener noreferrer"}},[e._v("advice"),t("OutboundLink")],1),e._v(": "),t("em",[e._v('"The simplest way to prevent overfitting is to start with a small model:"')]),e._v(". We hope this work will attract other data scientists to this bitcoin problem, improving the model. We also think that a longer time for the data collection is needed to capture various situations.")]),e._v(" "),t("p",[e._v("A significant part of a ML model are the activation functions, "),t("code",[e._v("relu")]),e._v(" (Rectified Linear Unit) is one of the most used lately, because it's simple and works well as we learned in this "),t("a",{attrs:{href:"https://youtu.be/aircAruvnKk?t=1035",target:"_blank",rel:"noopener noreferrer"}},[e._v("introducing neural network video"),t("OutboundLink")],1),e._v(". "),t("code",[e._v("relu")]),e._v(" it's equal to zero for negative values and equal to the input for positive values. Being non-linear allows the whole model to be non-linear.")]),e._v(" "),t("p",[e._v("For the last layer it is different: we want to enforce a minimum for the output, which is the minimum relay fee "),t("code",[e._v("1.0")]),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn3",id:"fnref3"}},[e._v("[3]")])]),e._v(". One could not simply cut the output of the model after prediction because all the training would not consider this constraint. So we need to build a custom activation function that the model training will be able to use for the "),t("a",{attrs:{href:"https://en.wikipedia.org/wiki/Gradient_descent#:~:text=Gradient%20descent%20is%20a%20first,the%20direction%20of%20steepest%20descent.",target:"_blank",rel:"noopener noreferrer"}},[e._v("gradient descent"),t("OutboundLink")],1),e._v(" optimization step. Luckily this is very simple using tensorflow primitives:")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("def clip(x):\n min = tf.constant(1.0)\n return tf.where(tf.less(x, min), min, x)\n")])])]),t("p",[e._v("Another important part is the optimizer, when we first read the aforementioned "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/keras/regression",target:"_blank",rel:"noopener noreferrer"}},[e._v("example"),t("OutboundLink")],1),e._v(" the optimizer used was "),t("code",[e._v("RMSProp")]),e._v(" however the example updated lately and we noticed the optimizer changed in favor of "),t("code",[e._v("Adam")]),e._v(" which we read is the "),t("a",{attrs:{href:"https://towardsdatascience.com/adam-latest-trends-in-deep-learning-optimization-6be9a291375c",target:"_blank",rel:"noopener noreferrer"}},[e._v("latest trend"),t("OutboundLink")],1),e._v(" in data science. We changed the model to use "),t("code",[e._v("Adam")]),e._v(" and effectively the training is faster with "),t("code",[e._v("Adam")]),e._v(" and even slightly lower error is achieved.\nAnother important parameter is the learning rate, which we set to "),t("code",[e._v("0.01")]),e._v(" after manual trials; however there might be space for improvements such as using "),t("a",{attrs:{href:"https://www.tensorflow.org/api_docs/python/tf/compat/v1/train/exponential_decay",target:"_blank",rel:"noopener noreferrer"}},[e._v("exponential decay"),t("OutboundLink")],1),e._v(", starting with an high learning rate and decreasing it through training epochs.")]),e._v(" "),t("p",[e._v('The last part of the model configuration is the loss function: the objective of the training is to find the minimum of this function. Usually for regression problem (the ones having a number as output, not a category) the most used is the Mean squared error (MSE). MSE is measured as the average of squared difference between predictions and actual observations, giving larger penalties to large difference because of the square. An interesting property is that the bigger the error the faster the changes is good at the beginning of the training, while slowing down when the model predicts better is desirable to avoid "jumping out" the local minimum.')]),e._v(" "),t("h4",{attrs:{id:"finally-the-model-training"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#finally-the-model-training"}},[e._v("#")]),e._v(" Finally, the model training")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("PATIENCE = 20\nMAX_EPOCHS = 200\n\ndef train():\n early_stop = keras.callbacks.EarlyStopping(monitor='val_loss', patience=PATIENCE)\n history = model.fit(train_ds, epochs=MAX_EPOCHS, validation_data=val_ds, verbose=1, callbacks=[early_stop])\n return history\n\nhistory = train()\n")])])]),t("p",[e._v("This steps is the core of the neural network, it takes a while, let's analyze the output:")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("Epoch 1/200\n7559/7559 [==============================] - 34s 3ms/step - loss: 547.8023 - mae: 16.9547 - mse: 547.8023 - val_loss: 300.5965 - val_ma\ne: 11.9202 - val_mse: 300.5965\n...\nEpoch 158/200\n7559/7559 [==============================] - 31s 3ms/step - loss: 163.2548 - mae: 8.3126 - mse: 163.2548 - val_loss: 164.8296 - val_mae: 8.3402 - val_mse: 164.8296\n")])])]),t("p",[e._v("Training is done in epochs, under every epoch all the training data is iterated and model parameters updated to minimize the loss function.")]),e._v(" "),t("p",[e._v("The number "),t("code",[e._v("7559")]),e._v(" represent the number of steps. Theoretically the whole training data should be processed at once and parameters updated accordingly, however in practice this is infeasible for example for memory resource, thus the training happens in batch. In our case we have "),t("code",[e._v("1,934,999")]),e._v(" observations in the training set and our batch size is "),t("code",[e._v("256")]),e._v(", thus we have "),t("code",[e._v("1,437,841/256=7,558.58")]),e._v(" which by excess result in "),t("code",[e._v("7559")]),e._v(" steps.")]),e._v(" "),t("p",[e._v("The "),t("code",[e._v("~31s")]),e._v(" is the time it takes to process the epoch on a threadripper CPU but GPU or TPU could do better.")]),e._v(" "),t("p",[e._v("The value "),t("code",[e._v("loss")]),e._v(" is the MSE on the training data while "),t("code",[e._v("val_loss")]),e._v(" is the MSE value on the validation data. As far as we understand the separated validation data helps to detect the machine learning enemy, overfitting. Because in case of overfitting the value "),t("code",[e._v("loss")]),e._v(" continue to improve (almost indefinitely) while "),t("code",[e._v("val_loss")]),e._v(" start improving with the loss but a certain point diverge, indicating the network is memorizing the training data to improve "),t("code",[e._v("loss")]),e._v(" but in doing so losing generalizing capabilities.")]),e._v(" "),t("p",[e._v("Our model doesn't look to suffer overfitting cause "),t("code",[e._v("loss")]),e._v(" and "),t("code",[e._v("val_loss")]),e._v(" doesn't diverge during training")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-train-history.png",alt:"train history"}})]),e._v(" "),t("p",[e._v("While we told the training to do 200 epochs, the training stopped at 158 because we added an "),t("code",[e._v("early_stop")]),e._v(" call back with "),t("code",[e._v("20")]),e._v(" as "),t("code",[e._v("PATIENCE")]),e._v(", meaning that after 20 epoch and no improvement in "),t("code",[e._v("val_loss")]),e._v(" the training is halted, saving time and potentially avoiding overfitting.")]),e._v(" "),t("h2",{attrs:{id:"the-prediction-phase"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#the-prediction-phase"}},[e._v("#")]),e._v(" The prediction phase")]),e._v(" "),t("p",[e._v("A "),t("a",{attrs:{href:"https://github.com/RCasatta/estimate_ml_fee",target:"_blank",rel:"noopener noreferrer"}},[e._v("prediction test tool"),t("OutboundLink")],1),e._v(" is available on github. At the moment it uses a bitcoin core node to provide network data for simplicity, but it queries it only for the mempool and the last 6 blocks, so it's something that also a light-client could do"),t("sup",{staticClass:"footnote-ref"},[t("a",{attrs:{href:"#fn4",id:"fnref4"}},[e._v("[4]")])]),e._v(".")]),e._v(" "),t("p",[e._v("The following chart is probably the best visualization to evaluate the model, on the x axis there is the real fee rate while on the y axis there is the prediction, the more the points are centered on the bisection, the more the model is good.\nWe can see the model is doing quite well, the MAE is 8 which is way lower than "),t("code",[e._v("estimatesmartfee")]),e._v(". However, there are big errors some times, in particular for prediction for fast confirmation ("),t("code",[e._v("confirms_in=1 or confirms_in=2")]),e._v(") as shown by the orange points. Creating a model only for blocks target greater than 2 instead of simply remove some observations may be an option.")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-true-and-predictions.png",alt:"prediction results"}})]),e._v(" "),t("p",[e._v("The following chart is instead a distribution of the errors, which for good model should resemble the normal distribution centered in 0, and it loooks like the model is respecting that.")]),e._v(" "),t("figure",[t("img",{attrs:{src:"/img/fee-estimation-for-light-clients/20210125-091313-error-distribution.png",alt:"error distribution"}})]),e._v(" "),t("h2",{attrs:{id:"conclusion-and-future-development"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#conclusion-and-future-development"}},[e._v("#")]),e._v(" Conclusion and future development")]),e._v(" "),t("p",[e._v("The results have shown deep neural network are a tool capable of good bitcoin transaction fee estimations; this suggests that further ML research in this area might be promising.")]),e._v(" "),t("p",[e._v("This is just a starting point, there are many future improvements such as:")]),e._v(" "),t("ul",[t("li",[e._v("Build a separate model with full knowledge, thus for full, always-connected nodes could be interesting and improve network resource allocation with respect to current estimators.")]),e._v(" "),t("li",[e._v("Tensorflow is a huge dependency, and since it contains all the feature to build and train a model, most of the feature are not needed in the prediction phase. In fact tensorflow lite exists which is specifically created for embedded and mobile devices; the "),t("a",{attrs:{href:"https://github.com/RCasatta/estimate_ml_fee",target:"_blank",rel:"noopener noreferrer"}},[e._v("prediction test tool"),t("OutboundLink")],1),e._v(" and the final integration in "),t("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk",target:"_blank",rel:"noopener noreferrer"}},[e._v("bdk"),t("OutboundLink")],1),e._v(" should use it.")]),e._v(" "),t("li",[e._v("Explore other fields to improve model predictions such as:\n"),t("ul",[t("li",[e._v("A bucket array of the transactions in the last 6 blocks with known fee rates. This should in particular help estimations with almost empty mempool.")]),e._v(" "),t("li",[e._v("Transaction weight")]),e._v(" "),t("li",[e._v("Time from last block")])])]),e._v(" "),t("li",[e._v("Some fields are very important and could benefit from pre-processing expansion, for instance applying "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/structured_data/feature_columns#hashed_feature_columns",target:"_blank",rel:"noopener noreferrer"}},[e._v("hashed feature columns"),t("OutboundLink")],1),e._v(" to "),t("code",[e._v("confirms_in")]),e._v(".")]),e._v(" "),t("li",[e._v("Bitcoin logger could be improved by a merge command to unify raw logs files, reducing redundancy and consequently disk occupation.")]),e._v(" "),t("li",[e._v("The dataset could be created in multiple files to allow more parallelism and use less memory during training.")]),e._v(" "),t("li",[e._v("Saving the dataset in "),t("a",{attrs:{href:"https://www.tensorflow.org/tutorials/load_data/tfrecord",target:"_blank",rel:"noopener noreferrer"}},[e._v("TFRecord format"),t("OutboundLink")],1),e._v(" instead of CSV")]),e._v(" "),t("li",[e._v("At the moment we are training the model on a threadripper CPU, training the code on GPU or even TPU will be needed to decrease training time, especially because input data will grow.")]),e._v(" "),t("li",[e._v("The "),t("a",{attrs:{href:"https://github.com/RCasatta/estimate_ml_fee",target:"_blank",rel:"noopener noreferrer"}},[e._v("prediction test tool"),t("OutboundLink")],1),e._v(" should estimate only using the p2p bitcoin network, without requiring a node. This work would be propedeutic for "),t("a",{attrs:{href:"https://github.com/bitcoindevkit/bdk",target:"_blank",rel:"noopener noreferrer"}},[e._v("bdk"),t("OutboundLink")],1),e._v(" integration")]),e._v(" "),t("li",[e._v("At the moment mempool buckets are multiple inputs "),t("code",[e._v("a*")]),e._v(" as show in the model graph; since they are related, is it possible to merge them in one TensorArray?")]),e._v(" "),t("li",[e._v("Sometimes the model does not learn and "),t("a",{attrs:{href:"https://github.com/RCasatta/bitcoin_logger/blob/master/notes.md",target:"_blank",rel:"noopener noreferrer"}},[e._v("gets stuck"),t("OutboundLink")],1),e._v(". The reason is the "),t("code",[e._v("clip")]),e._v(" function applied in the last layer is constant for a value lower than 1. In this case, the derivative is 0 and the gradient descent doesn't know where to go. Instead of using the "),t("code",[e._v("clip")]),e._v(" function apply penalties to the loss function for values lower than 1.")]),e._v(" "),t("li",[e._v("There are issues regarding dead neurons (going to 0) or neurons with big weight, weight results should be monitored for this events, and also weight decay and L2 regularization should be explored.")]),e._v(" "),t("li",[e._v("Tune hyper-parameters technique should be re-tested.")]),e._v(" "),t("li",[e._v("Predictions should be monotonic decreasing for growing "),t("code",[e._v("confirms_in")]),e._v(" parameter; for obvious reason it doesn't make sense that an higher fee rate will result in a higher confirmation time. But since this is not enforced anywhere in the model, at the moment this could happen.")]),e._v(" "),t("li",[e._v("Since nodes with bloom filter disabled doesn't serve the mempool anymore, a model based only on last blocks should be evaluated.")])]),e._v(" "),t("h2",{attrs:{id:"acknowledgements"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#acknowledgements"}},[e._v("#")]),e._v(" Acknowledgements")]),e._v(" "),t("p",[e._v("Thanks to "),t("a",{attrs:{href:"https://squarecrypto.org/",target:"_blank",rel:"noopener noreferrer"}},[e._v("Square crypto"),t("OutboundLink")],1),e._v(" for sponsoring this work and thanks to the reviewers: "),t("a",{attrs:{href:"https://twitter.com/LeoComandini",target:"_blank",rel:"noopener noreferrer"}},[e._v("Leonardo Comandini"),t("OutboundLink")],1),e._v(", "),t("a",{attrs:{href:"https://twitter.com/domegabri",target:"_blank",rel:"noopener noreferrer"}},[e._v("Domenico Gabriele"),t("OutboundLink")],1),e._v(", "),t("a",{attrs:{href:"https://twitter.com/afilini",target:"_blank",rel:"noopener noreferrer"}},[e._v("Alekos Filini"),t("OutboundLink")],1),e._v(", "),t("a",{attrs:{href:"https://twitter.com/Ferdinando1970",target:"_blank",rel:"noopener noreferrer"}},[e._v("Ferdinando Ametrano"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("And also this tweet that remembered me "),t("a",{attrs:{href:"https://twitter.com/RCasatta",target:"_blank",rel:"noopener noreferrer"}},[e._v("I"),t("OutboundLink")],1),e._v(" had this work in my TODO list")]),e._v(" "),t("blockquote",{staticClass:"twitter-tweet"},[t("p",{attrs:{lang:"en",dir:"ltr"}},[e._v("I don't understand Machine Learning(ML), but is it horrible to use ML to predict bitcoin fees? "),t("br"),t("br"),e._v('I have heard tales of this "Deep Learning" thing where you throw a bunch of data at it and it gives you good results with high accuracy.')]),e._v("— sanket1729 (@sanket1729) "),t("a",{attrs:{href:"https://twitter.com/sanket1729/status/1336624662365822977?ref_src=twsrc%5Etfw"}},[e._v("December 9, 2020")])]),e._v(" "),t("script",{attrs:{async:"",src:"https://platform.twitter.com/widgets.js",charset:"utf-8"}}),e._v(" "),t("p",[e._v("This is the final part of the series. In the previous "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-1/"}},[e._v("Part 1")]),e._v(" we talked about the problem and in "),t("RouterLink",{attrs:{to:"/blog/2021/01/fee-estimation-for-light-clients-part-2/"}},[e._v("Part 2")]),e._v(" we talked about the dataset.")],1),e._v(" "),t("hr",{staticClass:"footnotes-sep"}),e._v(" "),t("section",{staticClass:"footnotes"},[t("ol",{staticClass:"footnotes-list"},[t("li",{staticClass:"footnote-item",attrs:{id:"fn1"}},[t("p",[e._v("MAE is Mean Absolute Error, which is the average of the series built by the absolute difference between the real value and the estimation. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref1"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn2"}},[t("p",[e._v("drift like MAE, but without the absolute value "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref2"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn3"}},[t("p",[e._v("Most node won't relay transactions with fee lower than the min relay fee, which has a default of "),t("code",[e._v("1.0")]),e._v(" "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref3"}},[e._v("↩︎")])])]),e._v(" "),t("li",{staticClass:"footnote-item",attrs:{id:"fn4"}},[t("p",[e._v("An important issue emerged after the article came out, a bitcoin core client with bloom filter disabled (default as of 0.21) doesn't serve the mempool via p2p. "),t("a",{staticClass:"footnote-backref",attrs:{href:"#fnref4"}},[e._v("↩︎")])])])])])])}),[],!1,null,null,null);t.default=s.exports}}]); \ No newline at end of file diff --git a/assets/js/25.139a3121.js b/assets/js/25.d5b3948e.js similarity index 99% rename from assets/js/25.139a3121.js rename to assets/js/25.d5b3948e.js index 47035b7e85..ffcc812fed 100644 --- a/assets/js/25.139a3121.js +++ b/assets/js/25.d5b3948e.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[25],{371:function(e,t,s){"use strict";s.r(t);var n=s(7),a=Object(n.a)({},(function(){var e=this,t=e._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This is the first of a two-parts blog series in which I will try to explain all the changes that I made to BDK (and some of its dependencies) to make our "),t("a",{attrs:{href:"https://twitter.com/afilini/status/1459763243556163584",target:"_blank",rel:"noopener noreferrer"}},[e._v("first Taproot transaction in mainnet"),t("OutboundLink")],1),e._v(", which also\nturned out to be "),t("a",{attrs:{href:"https://twitter.com/afilini/status/1459774394054725634",target:"_blank",rel:"noopener noreferrer"}},[e._v("the first ever use of the new "),t("code",[e._v("OP_CHECKSIGADD")]),e._v(" opcode"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("Hopefully this will give an insight into what kind of changes need to be made to a wallet in order to support spending "),t("code",[e._v("P2TR")]),e._v(" outputs, both with key-spend and script-spend. BDK actually delegates\nmost of the hard work to "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(", and luckily most of the Taproot code was already implemented by the time I started working on it. I only had to patch a few little bugs here and there, and it ended up\nworking flawlessly in the end.")]),e._v(" "),t("p",[e._v("In this first part I will focus on the changes made to our dependencies, "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(". In the second part I will talk about BDK itself.")]),e._v(" "),t("h2",{attrs:{id:"backstory"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#backstory"}},[e._v("#")]),e._v(" Backstory")]),e._v(" "),t("p",[e._v("On the evening of Thursday, November 11th I was attending our weekly "),t("a",{attrs:{href:"https://www.satoshispritz.com/",target:"_blank",rel:"noopener noreferrer"}},[e._v("Satoshi Spritz"),t("OutboundLink")],1),e._v(" meetup in Milan. The activation of Taproot was right around the corner, and naturally that was the main discussion\ntopic that night. The activation was forecasted for the early afternoon of Sunday, November 14th, a little less than 72h later.")]),e._v(" "),t("p",[e._v("I began to wonder how hard it would be to patch BDK and add support for Taproot. I knew most of the work had already been done in our main dependencies, "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(", and so I decided\nto challenge myself: could I make it in time for the activation?")]),e._v(" "),t("p",[e._v('The following day I started digging into the topic. It didn\'t help that up until that time I only had a rather "high level" idea of how Taproot worked, but luckily all the BIPs were very well written and\nstraightforward to understand.')]),e._v(" "),t("p",[e._v("By Friday night (or rather, early Saturday morning) "),t("a",{attrs:{href:"https://mempool.space/signet/tx/ba0ebb350717701ca4ea109aadfbaf3058f6cd73e5ece3927ddee653de06cf5a",target:"_blank",rel:"noopener noreferrer"}},[e._v("I had Taproot key-spend working"),t("OutboundLink")],1),e._v(", which made me pretty optimistic even though the activation date was actually moving closer, now being forecasted for\nSunday "),t("em",[e._v("morning")]),e._v(".")]),e._v(" "),t("p",[e._v("After a few hours of sleep I went back to work and by early Saturday afternoon "),t("a",{attrs:{href:"https://mempool.space/signet/tx/41d7d49f9f4edffa9ca88ad6fb887fbf1ae68f9f31def267fdb3a5949f766bf5",target:"_blank",rel:"noopener noreferrer"}},[e._v("I had Taproot script-spend working as well"),t("OutboundLink")],1),e._v(". This left me a few hours to coordinate with some friends and "),t("a",{attrs:{href:"https://mempool.space/address/1Taproote7gvQGKz5g982ecSbPvqJhMUf",target:"_blank",rel:"noopener noreferrer"}},[e._v("generate a vanity address"),t("OutboundLink")],1),e._v("\nto deposit funds into temporarily, as we didn't trust sending them to Taproot addresses before the activation (as they were anyone-can-spend according to the pre-activation rules).")]),e._v(" "),t("p",[e._v("After another pretty short night, I woke up a 5:30 AM on Sunday to monitor the activation. I broadcasted our transactions shortly after 6:00 AM as the activation block was being mined. Unfortunately, the first\nthree blocks that were enforcing Taproot rules "),t("a",{attrs:{href:"https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-November/019598.html",target:"_blank",rel:"noopener noreferrer"}},[e._v("didn't include any Taproot transaction"),t("OutboundLink")],1),e._v(", which indicates that the miners weren't actually running the new Bitcoin Core 22.0 nodes. The fourth block, mined by "),t("code",[e._v("Foundry USA")]),e._v(" "),t("a",{attrs:{href:"https://mempool.space/tx/2eb8dbaa346d4be4e82fe444c2f0be00654d8cfd8c4a9a61b11aeaab8c00b272",target:"_blank",rel:"noopener noreferrer"}},[e._v("included my transaction"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://twitter.com/achow101/status/1459760452775387136?s=20",target:"_blank",rel:"noopener noreferrer"}},[e._v("a few others"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("In the end our transaction was the third Taproot script-spend in the block, but the first to use the new "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0342.mediawiki#script-execution",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("OP_CHECKSIGADD")]),t("OutboundLink")],1),e._v(" opcode, as the two preceding it were respectively "),t("a",{attrs:{href:"https://mempool.space/tx/37777defed8717c581b4c0509329550e344bdc14ac38f71fc050096887e535c8",target:"_blank",rel:"noopener noreferrer"}},[e._v("a single-sig"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://mempool.space/tx/905ecdf95a84804b192f4dc221cfed4d77959b81ed66013a7e41a6e61e7ed530",target:"_blank",rel:"noopener noreferrer"}},[e._v("a 2-of-2 multisig"),t("OutboundLink")],1),e._v("\nscript, made with with two "),t("code",[e._v("OP_CHECKSIG(VERIFY)")]),e._v("s.")]),e._v(" "),t("p",[e._v("Now, with the context out of the way, we can begin talking about the code!")]),e._v(" "),t("h2",{attrs:{id:"rust-bitcoin"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#rust-bitcoin"}},[e._v("#")]),e._v(" rust-bitcoin")]),e._v(" "),t("p",[e._v("The first dependency I had to update was "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(". Most of the taproot stuff were already merged in "),t("code",[e._v("master")]),e._v(" (altough they hadn't been released yet). One notable missing part was the support for "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0371.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP371")]),t("OutboundLink")],1),e._v(",\nwhich is an extension of "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP174")]),t("OutboundLink")],1),e._v(", aka the "),t("code",[e._v("Partially Signed Bitcoin Transaction")]),e._v(" BIP. This new BIP defines a few new fields that are required to properly handle Taproot transactions.")]),e._v(" "),t("p",[e._v("Luckily most of the work had already been done by "),t("a",{attrs:{href:"https://twitter.com/sanket1729",target:"_blank",rel:"noopener noreferrer"}},[e._v("sanket1729"),t("OutboundLink")],1),e._v(", so I forked his branch and made only few very minor changes, just to expose a structure that I will have to use later which in his code wasn't public.")]),e._v(" "),t("p",[e._v("You can find all the commits mentioned here in "),t("a",{attrs:{href:"https://github.com/afilini/rust-bitcoin/tree/taproot-testing",target:"_blank",rel:"noopener noreferrer"}},[e._v("my rust-bitcoin "),t("code",[e._v("taproot-testing")]),e._v(" branch"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git diff 187234f f830df9\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("diff --git a/src/lib.rs b/src/lib.rs\nindex 87d9c36..d5e5802 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("@@ -54,7 +54,6 @@")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_mut)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(dead_code)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_imports)]\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(missing_docs)]\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_must_use)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(broken_intra_doc_links)]\n")])]),e._v("\ndiff --git a/src/util/taproot.rs b/src/util/taproot.rs\nindex 674eeee..3d56cbc 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/util/taproot.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/util/taproot.rs")]),e._v("\n@@ -440,7 +440,7 @@ impl TaprootBuilder {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("// Internally used structure to represent the node information in taproot tree\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]\n')])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("pub(crate) struct NodeInfo {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("pub struct NodeInfo {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" /// Merkle Hash for this node\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub(crate) hash: sha256::Hash,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" /// information about leaves inside this node\n")])]),e._v("@@ -448,8 +448,12 @@ pub(crate) struct NodeInfo {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("}\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("impl NodeInfo {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn hash(&self) -> &sha256::Hash {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" &self.hash\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Create a new NodeInfo with omitted/hidden info\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn new_hidden(hash: sha256::Hash) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn new_hidden(hash: sha256::Hash) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Self {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" hash: hash,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" leaves: vec![],\n")])]),e._v("@@ -457,7 +461,7 @@ impl NodeInfo {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Create a new leaf with NodeInfo\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn new_leaf_with_ver(script: Script, ver: LeafVersion) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn new_leaf_with_ver(script: Script, ver: LeafVersion) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let leaf = LeafInfo::new(script, ver);\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Self {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" hash: leaf.hash(),\n")])]),e._v("@@ -466,7 +470,7 @@ impl NodeInfo {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Combine two NodeInfo's to create a new parent\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn combine(a: Self, b: Self) -> Result {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn combine(a: Self, b: Self) -> Result {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut all_leaves = Vec::with_capacity(a.leaves.len() + b.leaves.len());\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for mut a_leaf in a.leaves {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" a_leaf.merkle_branch.push(b.hash)?; // add hashing partner\n")])]),e._v("\n")])])]),t("p",[e._v("There isn't much to explain here: I disabled the "),t("code",[e._v("missing_docs")]),e._v(" lint so that the compiler wouldn't complain about the new public methods that aren't documented.\nThen, I added a getter for the "),t("code",[e._v("hash")]),e._v(" field of "),t("code",[e._v("NodeInfo")]),e._v(" and made the struct itself and a bunch of methods public.")]),e._v(" "),t("p",[e._v('We will use this structure later to recover the merkle root of a Taproot script tree, given one leaf and the other "hidden" branches.')]),e._v(" "),t("h2",{attrs:{id:"rust-miniscript"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#rust-miniscript"}},[e._v("#")]),e._v(" rust-miniscript")]),e._v(" "),t("p",[e._v("Moving on to "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(': once again, most of the work required to support Taproot had already been done, but this time I was working with very "early" prototype-like code, so I was prepared to\nmake some changes to the code to get it to work how I wanted.')]),e._v(" "),t("p",[e._v("Instead of showing one big diff I will talk about the commits individually, which I think will help making more clear what I was doing.")]),e._v(" "),t("p",[e._v("Once again, you can find all the commits referenced here in "),t("a",{attrs:{href:"https://github.com/afilini/rust-miniscript/tree/taproot",target:"_blank",rel:"noopener noreferrer"}},[e._v("my rust-miniscript "),t("code",[e._v("taproot")]),e._v(" branch"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 34cf15b\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 34cf15b3aac1d8c2693af1b9749b888f3f29e510\nAuthor: Alekos Filini \nDate: Fri Nov 12 12:06:35 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Fix TapTree iter depth\n")])]),e._v("\ndiff --git a/src/descriptor/tr.rs b/src/descriptor/tr.rs\nindex 79d3c05..314c7f4 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/tr.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/tr.rs")]),e._v("\n@@ -65,7 +65,7 @@ impl TapTree {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" /// Iterate over all miniscripts\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn iter(&self) -> TapTreeIter {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTreeIter { stack: vec![self] }\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTreeIter { stack: vec![(0, self)] }\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Helper function to translate keys\n")])]),e._v("@@ -262,7 +262,7 @@ pub struct TapTreeIter<'a, Pk: MiniscriptKey>\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("where\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Pk: 'a,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("{\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" stack: Vec<&'a TapTree>,\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" stack: Vec<(usize, &'a TapTree)>,\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("}\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("impl<'a, Pk> Iterator for TapTreeIter<'a, Pk>\n")])]),e._v("@@ -273,13 +273,13 @@ where\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn next(&mut self) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" while !self.stack.is_empty() {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let last = self.stack.pop().expect("Size checked above");\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let (depth, last) = self.stack.pop().expect("Size checked above");\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match &*last {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTree::Tree(l, r) => {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push(&r);\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push(&l);\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push((depth + 1, &r));\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push((depth + 1, &l));\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTree::Leaf(ref ms) => return Some((self.stack.len(), ms)),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTree::Leaf(ref ms) => return Some((depth, ms)),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" None\n")])])])])]),t("p",[t("code",[e._v("TapTreeIterator")]),e._v(" is an iterator that goes through a "),t("code",[e._v("TapTree")]),e._v(" and yields a "),t("code",[e._v("(depth, node)")]),e._v(" pair. This is then fed to "),t("a",{attrs:{href:"https://github.com/afilini/rust-miniscript/blob/taproot/src/descriptor/tr.rs#L183-L189",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("TaprootBuilder")]),t("OutboundLink")],1),e._v(", which returns an error if trying to insert nodes\nin "),t("a",{attrs:{href:"https://github.com/afilini/rust-bitcoin/blob/taproot-testing/src/util/taproot.rs#L403-L405",target:"_blank",rel:"noopener noreferrer"}},[e._v("an order that is not DFS"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("The way the depth was computed before made the builder always fail for non-trivial trees (i.e. more than 1 node).")]),e._v(" "),t("p",[e._v("Here I decided to play the safe card, and just keep track of the depth explicitly: I think there might be a way to compute the depth just knowing the "),t("code",[e._v("self.stack.len()")]),e._v(" (assuming the tree has a specific structure,\nwhich I'm not sure applies here), but anyway I didn't have much time to think about it and I just went for the \"dumb but idiot-proof\" way which ended up working fine.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show f4a3459\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit f4a3459128e37ca0c2701b8b6da064d4952296ff\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:15:52 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Switch rust-bitcoin rev\n")])]),e._v("\ndiff --git a/Cargo.toml b/Cargo.toml\nindex 12825e8..8240024 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/Cargo.toml")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/Cargo.toml")]),e._v('\n@@ -17,7 +17,7 @@ rand = ["bitcoin/rand"]\n\n'),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("[dependencies]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('# bitcoin = "0.27"\n')])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('bitcoin = {git = "https://github.com/sanket1729/rust-bitcoin", branch = "taproot_psbt"}\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('bitcoin = { git = "https://github.com/afilini/rust-bitcoin.git", branch = "taproot-testing" }\n')])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("[dependencies.serde]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('version = "1.0"\n')])])])])]),t("p",[e._v("Trivial commit, switch to "),t("a",{attrs:{href:"https://github.com/afilini/rust-bitcoin/tree/taproot-testing",target:"_blank",rel:"noopener noreferrer"}},[e._v("my fork of rust-bitcoin"),t("OutboundLink")],1),e._v(" so that I can make changes if necessary.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 0446b16\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 0446b1631cec9f7118d46f0f4c94ccd20de29f94\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:25:18 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Parse x-only keys\n")])]),e._v("\ndiff --git a/src/descriptor/key.rs b/src/descriptor/key.rs\nindex 4108d00..b7f90b5 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/key.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/key.rs")]),e._v("\n@@ -283,9 +283,9 @@ impl FromStr for DescriptorPublicKey {\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn from_str(s: &str) -> Result {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' // A "raw" public key without any origin is the least we accept.\n')])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if s.len() < 66 {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if s.len() < 64 {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" return Err(DescriptorKeyParseError(\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' "Key too short (<66 char), doesn\'t match any format",\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' "Key too short (<64 char), doesn\'t match any format",\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" ));\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n@@ -301,6 +301,14 @@ impl FromStr for DescriptorPublicKey {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" derivation_path,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" wildcard,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }))\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else if key_part.len() == 64 {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // x-only pubkey, prefix it with `02`\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let key = bitcoin::PublicKey::from_str(&format!("02{}", key_part))\n')]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' .map_err(|_| DescriptorKeyParseError("Error while parsing x-only public key"))?;\n')]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Ok(DescriptorPublicKey::SinglePub(DescriptorSinglePub {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" key,\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" origin,\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }))\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if key_part.len() >= 2\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' && !(&key_part[0..2] == "02" || &key_part[0..2] == "03" || &key_part[0..2] == "04")\n')])]),e._v("diff --git a/src/lib.rs b/src/lib.rs\nindex e168b16..3a2335e 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("@@ -95,8 +95,6 @@")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(non_snake_case)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_mut)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(dead_code)]\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_imports)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(missing_docs)]\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("pub extern crate bitcoin;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('#[cfg(feature = "serde")]\n')])])])])]),t("p",[e._v("This, I'm not really sure of: Taproot uses x-only public keys, which means that the first byte (which is usually a "),t("code",[e._v("03")]),e._v(" or a "),t("code",[e._v("02")]),e._v(") that indicates the parity of the EC point is completely dropped, and it's implicit\nthat the point is even (= "),t("code",[e._v("02")]),e._v("). Check out "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP340")]),t("OutboundLink")],1),e._v(" for a much better explanation.")]),e._v(" "),t("p",[e._v("So here when I find a string that is only 64 characters long I will assume it's an x-only pubkey, and I will parse it as a normal "),t("code",[e._v("bitcoin::PublicKey")]),e._v(" by prefixing it with "),t("code",[e._v("02")]),e._v(".")]),e._v(" "),t("p",[e._v("I guess one alternative could have been to try and parse it as a "),t("code",[e._v("schnorr::PublicKey")]),e._v(' and then "convert" it to a '),t("code",[e._v("ecdsa::PublicKey")]),e._v(" which should be supported, but once again I just wanted to get it done quickly and\nthis worked fine.")]),e._v(" "),t("p",[e._v("I also disabled the "),t("code",[e._v("unused_imports")]),e._v(" and "),t("code",[e._v("missing_docs")]),e._v(" lint so that the compiler wouldn't whine too much.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 87316ff\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 87316fffd06ab3bdf300fd1a958ddaa2789a6696\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:26:01 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Parse `tr()` descriptors\n")])]),e._v("\ndiff --git a/src/descriptor/mod.rs b/src/descriptor/mod.rs\nindex 06d98e1..4190786 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/mod.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/mod.rs")]),e._v("\n@@ -610,6 +610,7 @@ where\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("wpkh", 1) => Descriptor::Wpkh(Wpkh::from_tree(top)?),\n')]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("sh", 1) => Descriptor::Sh(Sh::from_tree(top)?),\n')]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("wsh", 1) => Descriptor::Wsh(Wsh::from_tree(top)?),\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("tr", _) => Descriptor::Tr(Tr::from_tree(top)?),\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => Descriptor::Bare(Bare::from_tree(top)?),\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" })\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("diff --git a/src/expression.rs b/src/expression.rs\nindex 1cef614..11a68d3 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/expression.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/expression.rs")]),e._v("\n@@ -100,7 +100,12 @@ impl<'a> Tree<'a> {\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" sl = &sl[n + 1..];\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" loop {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let (arg, new_sl) = Tree::from_slice_helper_round(sl, depth + 1)?;\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let (arg, new_sl) = if sl.contains('{') {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Tree::from_slice_helper_curly(sl, depth + 1)?\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Tree::from_slice_helper_round(sl, depth + 1)?\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" };\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" ret.args.push(arg);\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if new_sl.is_empty() {\n")])])])])]),t("p",[e._v("When trying to parse a descriptor (essentially turning a recursive string of "),t("code",[e._v("operator(args)")]),e._v(" into an abstract tree in memory) use a "),t("em",[e._v("curly-bracket-aware")]),e._v(" parser if there is one in the string.")]),e._v(" "),t("p",[e._v("The code to then build a "),t("code",[e._v("Tr")]),e._v(" struct given an "),t("code",[e._v("expression::Tree")]),e._v(" (and the "),t("code",[e._v("from_slice_helper_curly")]),e._v(" function) were already implemented, so it was just a matter of correctly\nbuilding the abstract tree by parsing curly brackets in descriptors.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 3055cab\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 3055cabef8bd51eda344ce501b03c533fd367b4f\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:26:30 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Fix control block creation when satisfying `Tr`\n")])]),e._v("\ndiff --git a/src/descriptor/tr.rs b/src/descriptor/tr.rs\nindex 314c7f4..8487d56 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/tr.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/tr.rs")]),e._v("\n@@ -571,17 +571,14 @@ impl DescriptorTrait for Tr {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let ver = LeafVersion::default();\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let leaf_script = (ms.encode(), ver);\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let control_block_set = spend_info\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .as_script_map()\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .get(&leaf_script)\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' .expect("Control block must exist in script map for every known leaf");\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // let control_block_set = spend_info\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // .as_script_map()\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // .get(&leaf_script)\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' // .expect("Control block must exist in script map for every known leaf");\n')]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let control_block = spend_info.control_block(&leaf_script).expect("Control block must exist in script map for every known leaf");\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" wit.push(leaf_script.0.into_bytes()); // Push the leaf script\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // There can be multiple control blocks for a (script, ver) pair\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Find the smallest one amongst those\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let control_block = control_block_set\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .iter()\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .min_by(|x, y| x.as_inner().len().cmp(&y.as_inner().len()))\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' .expect("Atleast one control must exist for a known leaf");\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" wit.push(control_block.serialize());\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Finally, save the minimum\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" min_wit = Some(wit);\n")])]),e._v("\n")])])]),t("p",[e._v("This is where things get more interesting: this section of code builds the witness to satisfy a Taproot descriptor. In case of a script-spend, we need to prove that the script we are using had been committed\ninto the public key of our "),t("code",[e._v("P2TR")]),e._v(' input. We do this by adding a "control block", that contains data about the parity of the key, the leaf version used, and the merkle path from the leaf we are using to spend\nup to the merkle root, which is committed into the public key. Once again, this is explained very well in '),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP341")]),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("Before my patch the code was only getting the set of merkle paths that could lead from the root to the leaves that contain a given script. For context, the signature of "),t("code",[e._v("TaprootSpendInfo::as_script_map(&self)")]),e._v(" is:")]),e._v(" "),t("div",{staticClass:"language-rust extra-class"},[t("pre",{pre:!0,attrs:{class:"language-rust"}},[t("code",[t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// Access the internal script map")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("pub")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("fn")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token function-definition function"}},[e._v("as_script_map")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("->")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("BTreeMap")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("<")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Script")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("LeafVersion")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("BTreeSet")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("TaprootMerkleBranch")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v(">>")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("{")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("}")]),e._v("\n")])])]),t("p",[e._v('Then the code would look for the "shortest" path to that specific script, as it would save size in the final transaction (leaves that are more "deep" in the tree than others naturally have more hidden branches\nin their path to the root, and thus require a longer control block to reveal them all).')]),e._v(" "),t("p",[e._v("The issue here is that the "),t("code",[e._v("control_block")]),e._v(" variable is then serialized directly into the witness. But this is not a control block, it's just a set of merkle paths! A control block only has "),t("em",[e._v("one")]),e._v(" merkle path, and\nincludes the leaf version and the key parity bit.")]),e._v(" "),t("p",[e._v("Conveniently, the "),t("code",[e._v("TaprootSpendInfo")]),e._v(' struct also has this other method (I\'m including the implementation as well, because it shows that internally it does the same "trick" to find the shortest path):')]),e._v(" "),t("div",{staticClass:"language-rust extra-class"},[t("pre",{pre:!0,attrs:{class:"language-rust"}},[t("code",[t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// Obtain a [`ControlBlock`] for particular script with the given version.")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// Returns [`None`] if the script is not contained in the [`TaprootSpendInfo`]")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// If there are multiple ControlBlocks possible, this returns the shortest one.")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("pub")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("fn")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token function-definition function"}},[e._v("control_block")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" script_ver"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Script")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("LeafVersion")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("->")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Option")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("ControlBlock")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v(">")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("{")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("let")]),e._v(" merkle_branch_set "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("=")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),e._v("script_map"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("get")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),e._v("script_ver"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("?")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(";")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("// Choose the smallest one amongst the multiple script maps")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("let")]),e._v(" smallest "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("=")]),e._v(" merkle_branch_set\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("iter")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("min_by")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token closure-params"}},[t("span",{pre:!0,attrs:{class:"token closure-punctuation punctuation"}},[e._v("|")]),e._v("x"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" y"),t("span",{pre:!0,attrs:{class:"token closure-punctuation punctuation"}},[e._v("|")])]),e._v(" x"),t("span",{pre:!0,attrs:{class:"token number"}},[e._v(".0")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("len")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("cmp")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),e._v("y"),t("span",{pre:!0,attrs:{class:"token number"}},[e._v(".0")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("len")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("expect")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[e._v('"Non-empty iterator"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(";")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Some")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("ControlBlock")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("{")]),e._v("\n internal_key"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),e._v("internal_key"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n output_key_parity"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),e._v("output_key_parity"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n leaf_version"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("LeafVersion")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("::")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("default")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n merkle_branch"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" smallest"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("clone")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("}")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("}")]),e._v("\n")])])]),t("p",[e._v("So to fix this code we just have to use that method instead, and we can get it done in one single line!")]),e._v(" "),t("p",[e._v('Instead of removing the old code at the time I only commented it out, because I initially thought I would still have to look for the shortest script myself, and I figured the "sorting" code would come in handy\nlater on.')]),e._v(" "),t("p",[e._v("Also, if you are an acute observer, you might have noticed that there's a bug in this last snippet of code. Feel free to think about it a little bit, then check out the "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin/pull/703",target:"_blank",rel:"noopener noreferrer"}},[e._v("PR"),t("OutboundLink")],1),e._v(" I made\nif you wanna know the answer!")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("git show 35378ad\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 35378ad01a6f2b8161a3f36448b24d031f8aeaec\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:27:14 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Consider key-spend max satisfaction weight\n")])]),e._v("\ndiff --git a/src/descriptor/tr.rs b/src/descriptor/tr.rs\nindex 8487d56..fabf860 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/tr.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/tr.rs")]),e._v("\n@@ -593,7 +593,7 @@ impl DescriptorTrait for Tr {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn max_satisfaction_weight(&self) -> Result {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut max_wieght = None;\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut max_wieght = Some(65);\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for (depth, ms) in self.iter_scripts() {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let script_size = ms.script_size();\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let max_sat_elems = match ms.max_satisfaction_witness_elements() {\n")])])])])]),t("p",[e._v("This is a little bug in the code that tries to compute what the maximum satisfaction weight would be for a descriptor. For instance, we use this in BDK to compute how many extra sats of fees we need to pay\nin order to target a given fee rate, assuming the descriptor is satisfied with the worst (larger and most expensive) path.")]),e._v(" "),t("p",[e._v("For Taproot descriptors, it's just a matter of iterating over the leaves in the tree and pick the most expensive one... or is it? This doesn't take into account that Taproot outputs can also be spent with\nkey-spend, which means just pushing a signature to the witness. This signature is 64 bytes long when using the new "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("SIGHASH_DEFAULT")]),t("OutboundLink")],1),e._v(" sighash, or 65 otherwise. Since we are thinking about the maximum satisfaction\nweight, or the worst case possible, we naturally pick the latter.")]),e._v(" "),t("p",[e._v("Note that theoretically you could build a Taproot address \"without\" an available key-path spend (by using an unspendable Schnorr public key), but the code here in rust-miniscript doesn't take that into\naccount, as there's no way that I'm aware of to specificy in a "),t("code",[e._v("tr()")]),e._v(" descriptor that the key is unspendable. So, while theoretically here we should first check whether the key-spend path is available before\naccounting for its weight, in practice this is always true in miniscript so we just use that as our starting worst case and update it later if necessary while iterating the tree leaves.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show b4878f8\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit b4878f816e9ede11d5ed947c06e03aa988e3e26f\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:27:53 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Look for taproot stuff in psbts\n")])]),e._v("\ndiff --git a/src/psbt/mod.rs b/src/psbt/mod.rs\nindex 9a8b17d..42c6ce8 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/psbt/mod.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/psbt/mod.rs")]),e._v("\n@@ -25,13 +25,14 @@ use bitcoin;\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d};\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::secp256k1::{self, Secp256k1};\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::util::psbt::PartiallySignedTransaction as Psbt;\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::util::taproot::TapLeafHash;\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::Script;\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use interpreter;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use miniscript::limits::SEQUENCE_LOCKTIME_DISABLE_FLAG;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use miniscript::satisfy::{After, Older};\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use Satisfier;\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use {BitcoinECSig, Preimage32};\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use {BitcoinECSig, BitcoinSchnorrSig, Preimage32};\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use {MiniscriptKey, ToPublicKey};\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("mod finalizer;\n")])]),e._v("@@ -231,6 +232,24 @@ impl<'psbt> PsbtInputSatisfier<'psbt> {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("}\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("impl<'psbt, Pk: MiniscriptKey + ToPublicKey> Satisfier for PsbtInputSatisfier<'psbt> {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn lookup_tap_key_spend_sig(&self) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if let Some((sig, hash_ty)) = self.psbt.inputs[self.index].tap_key_sig {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Some(BitcoinSchnorrSig { sig, hash_ty })\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" None\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn lookup_tap_leaf_script_sig(&self, pk: &Pk, lh: &TapLeafHash) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let pk = pk.to_x_only_pubkey();\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if let Some((sig, hash_ty)) = self.psbt.inputs[self.index].tap_script_sigs.get(&(pk, *lh)) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Some(BitcoinSchnorrSig { sig: *sig, hash_ty: *hash_ty })\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" None\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn lookup_ec_sig(&self, pk: &Pk) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if let Some(rawsig) = self.psbt.inputs[self.index]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .partial_sigs\n")])])])])]),t("p",[e._v("This commit implements the Taproot-specific "),t("code",[e._v("Satisfier")]),e._v(" methods on "),t("code",[e._v("PsbtInputSatisfier")]),e._v(". The code to produce a valid witness (i.e. "),t("em",[e._v("satisfy")]),e._v(") a descriptor by looking for Taproot key-spend or script-spend signatures\nis already implemented, so it's just a matter of actually returning those, if they are present in a PSBT.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 80da0ba\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 80da0ba9b742b2dee23e7302e2f95a6e96b1d6ed\nAuthor: Alekos Filini \nDate: Sat Nov 13 16:54:27 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Iter keys in `MultiA`\n")])]),e._v("\ndiff --git a/src/miniscript/iter.rs b/src/miniscript/iter.rs\nindex 36c4b69..a54a371 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/miniscript/iter.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/miniscript/iter.rs")]),e._v("\n@@ -121,7 +121,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn get_leaf_pk(&self) -> Vec {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match self.node {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkK(ref key) => vec![key.clone()],\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) => keys.clone(),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) | Terminal::MultiA(_, ref keys) => keys.clone(),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => vec![],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("@@ -139,7 +139,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match self.node {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkH(ref hash) => vec![hash.clone()],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkK(ref key) => vec![key.to_pubkeyhash()],\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) => keys.iter().map(Pk::to_pubkeyhash).collect(),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) | Terminal::MultiA(_, ref keys) => keys.iter().map(Pk::to_pubkeyhash).collect(),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => vec![],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("@@ -155,7 +155,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match self.node {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkH(ref hash) => vec![PkPkh::HashedPubkey(hash.clone())],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkK(ref key) => vec![PkPkh::PlainPubkey(key.clone())],\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) => keys\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) | Terminal::MultiA(_, ref keys) => keys\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .into_iter()\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .map(|key| PkPkh::PlainPubkey(key.clone()))\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .collect(),\n")])]),e._v("@@ -170,7 +170,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn get_nth_pk(&self, n: usize) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match (&self.node, n) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::PkK(ref key), 0) => Some(key.clone()),\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) => keys.get(n).cloned(),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) | (&Terminal::MultiA(_, ref keys), _) => keys.get(n).cloned(),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => None,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("@@ -186,7 +186,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match (&self.node, n) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix 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unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => None,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("@@ -199,7 +199,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match (&self.node, n) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::PkH(ref hash), 0) => Some(PkPkh::HashedPubkey(hash.clone())),\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::PkK(ref key), 0) => Some(PkPkh::PlainPubkey(key.clone())),\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) => {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) | (&Terminal::MultiA(_, ref keys), _) => {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" keys.get(n).map(|key| PkPkh::PlainPubkey(key.clone()))\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => None,\n")])])])])]),t("p",[e._v("Taproot descriptors add a new miniscript operator called "),t("code",[e._v("multi_a()")]),e._v(" which behaves like "),t("code",[e._v("multi()")]),e._v(" in non-Taproot descriptors, but uses the new "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0342.mediawiki#script-execution",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("OP_CHECKSIGADD")]),t("OutboundLink")],1),e._v(" opcode when serialized in a script.")]),e._v(" "),t("p",[e._v("When this was added, somebody forgot to update the various methods that iterate over the public keys of a descriptor to correctly return the keys contained in "),t("code",[e._v("multi_a()")]),e._v(" - essentially, it was falling back in\nthe default case used by the operators that don't contain any key, but this one does!")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 8b108c5\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 8b108c5c0bf50b66b7220746525742b71f6cd4b4\nAuthor: Alekos Filini \nDate: Sat Nov 13 17:26:53 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Fix witness generation for `MultiA`\n")])]),e._v("\ndiff --git a/src/miniscript/satisfy.rs b/src/miniscript/satisfy.rs\nindex 655436e..ab43707 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/miniscript/satisfy.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/miniscript/satisfy.rs")]),e._v("\n@@ -1264,7 +1264,7 @@ impl Satisfaction {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Collect all available signatures\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut sig_count = 0;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut sigs = vec![vec![vec![]]; keys.len()];\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for (i, pk) in keys.iter().enumerate() {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for (i, pk) in keys.iter().rev().enumerate() {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match Witness::signature::<_, _, Ctx>(stfr, pk, leaf_hash) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Witness::Stack(sig) => {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" sigs[i] = sig;\n")])])])])]),t("p",[e._v("And finally, the last little fix: the "),t("code",[e._v("multi_a()")]),e._v(" operator is satisfied by pushing to the witness either a signature (if you have one available for that specific public key) or an empty vector. The problem is,\nthey have to be in the right order to match the order of public keys in your Taproot script.")]),e._v(" "),t("p",[e._v("rust-miniscript was pushing them in reverse order, so script validation was always failing for multisigs that had more than 1 key. Adding a "),t("code",[e._v(".rev()")]),e._v(" to the iterator fixed the issue.")]),e._v(" "),t("h2",{attrs:{id:"conclusion"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#conclusion"}},[e._v("#")]),e._v(" Conclusion")]),e._v(" "),t("p",[e._v("And that was it! We now have a fully working "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(" ready for Taproot.")]),e._v(" "),t("p",[e._v("In "),t("a",{attrs:{href:"/blog/2021/12/first-bdk-taproot-tx-look-at-the-code-part-2"}},[e._v("Part 2")]),e._v(" I will go over the code changes in BDK, but I think it's now time for you and I to take a break 😃")])])}),[],!1,null,null,null);t.default=a.exports}}]); \ No newline at end of file +(window.webpackJsonp=window.webpackJsonp||[]).push([[25],{370:function(e,t,s){"use strict";s.r(t);var n=s(7),a=Object(n.a)({},(function(){var e=this,t=e._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[t("p",[e._v("This is the first of a two-parts blog series in which I will try to explain all the changes that I made to BDK (and some of its dependencies) to make our "),t("a",{attrs:{href:"https://twitter.com/afilini/status/1459763243556163584",target:"_blank",rel:"noopener noreferrer"}},[e._v("first Taproot transaction in mainnet"),t("OutboundLink")],1),e._v(", which also\nturned out to be "),t("a",{attrs:{href:"https://twitter.com/afilini/status/1459774394054725634",target:"_blank",rel:"noopener noreferrer"}},[e._v("the first ever use of the new "),t("code",[e._v("OP_CHECKSIGADD")]),e._v(" opcode"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("Hopefully this will give an insight into what kind of changes need to be made to a wallet in order to support spending "),t("code",[e._v("P2TR")]),e._v(" outputs, both with key-spend and script-spend. BDK actually delegates\nmost of the hard work to "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(", and luckily most of the Taproot code was already implemented by the time I started working on it. I only had to patch a few little bugs here and there, and it ended up\nworking flawlessly in the end.")]),e._v(" "),t("p",[e._v("In this first part I will focus on the changes made to our dependencies, "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(". In the second part I will talk about BDK itself.")]),e._v(" "),t("h2",{attrs:{id:"backstory"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#backstory"}},[e._v("#")]),e._v(" Backstory")]),e._v(" "),t("p",[e._v("On the evening of Thursday, November 11th I was attending our weekly "),t("a",{attrs:{href:"https://www.satoshispritz.com/",target:"_blank",rel:"noopener noreferrer"}},[e._v("Satoshi Spritz"),t("OutboundLink")],1),e._v(" meetup in Milan. The activation of Taproot was right around the corner, and naturally that was the main discussion\ntopic that night. The activation was forecasted for the early afternoon of Sunday, November 14th, a little less than 72h later.")]),e._v(" "),t("p",[e._v("I began to wonder how hard it would be to patch BDK and add support for Taproot. I knew most of the work had already been done in our main dependencies, "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(", and so I decided\nto challenge myself: could I make it in time for the activation?")]),e._v(" "),t("p",[e._v('The following day I started digging into the topic. It didn\'t help that up until that time I only had a rather "high level" idea of how Taproot worked, but luckily all the BIPs were very well written and\nstraightforward to understand.')]),e._v(" "),t("p",[e._v("By Friday night (or rather, early Saturday morning) "),t("a",{attrs:{href:"https://mempool.space/signet/tx/ba0ebb350717701ca4ea109aadfbaf3058f6cd73e5ece3927ddee653de06cf5a",target:"_blank",rel:"noopener noreferrer"}},[e._v("I had Taproot key-spend working"),t("OutboundLink")],1),e._v(", which made me pretty optimistic even though the activation date was actually moving closer, now being forecasted for\nSunday "),t("em",[e._v("morning")]),e._v(".")]),e._v(" "),t("p",[e._v("After a few hours of sleep I went back to work and by early Saturday afternoon "),t("a",{attrs:{href:"https://mempool.space/signet/tx/41d7d49f9f4edffa9ca88ad6fb887fbf1ae68f9f31def267fdb3a5949f766bf5",target:"_blank",rel:"noopener noreferrer"}},[e._v("I had Taproot script-spend working as well"),t("OutboundLink")],1),e._v(". This left me a few hours to coordinate with some friends and "),t("a",{attrs:{href:"https://mempool.space/address/1Taproote7gvQGKz5g982ecSbPvqJhMUf",target:"_blank",rel:"noopener noreferrer"}},[e._v("generate a vanity address"),t("OutboundLink")],1),e._v("\nto deposit funds into temporarily, as we didn't trust sending them to Taproot addresses before the activation (as they were anyone-can-spend according to the pre-activation rules).")]),e._v(" "),t("p",[e._v("After another pretty short night, I woke up a 5:30 AM on Sunday to monitor the activation. I broadcasted our transactions shortly after 6:00 AM as the activation block was being mined. Unfortunately, the first\nthree blocks that were enforcing Taproot rules "),t("a",{attrs:{href:"https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-November/019598.html",target:"_blank",rel:"noopener noreferrer"}},[e._v("didn't include any Taproot transaction"),t("OutboundLink")],1),e._v(", which indicates that the miners weren't actually running the new Bitcoin Core 22.0 nodes. The fourth block, mined by "),t("code",[e._v("Foundry USA")]),e._v(" "),t("a",{attrs:{href:"https://mempool.space/tx/2eb8dbaa346d4be4e82fe444c2f0be00654d8cfd8c4a9a61b11aeaab8c00b272",target:"_blank",rel:"noopener noreferrer"}},[e._v("included my transaction"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://twitter.com/achow101/status/1459760452775387136?s=20",target:"_blank",rel:"noopener noreferrer"}},[e._v("a few others"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("In the end our transaction was the third Taproot script-spend in the block, but the first to use the new "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0342.mediawiki#script-execution",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("OP_CHECKSIGADD")]),t("OutboundLink")],1),e._v(" opcode, as the two preceding it were respectively "),t("a",{attrs:{href:"https://mempool.space/tx/37777defed8717c581b4c0509329550e344bdc14ac38f71fc050096887e535c8",target:"_blank",rel:"noopener noreferrer"}},[e._v("a single-sig"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://mempool.space/tx/905ecdf95a84804b192f4dc221cfed4d77959b81ed66013a7e41a6e61e7ed530",target:"_blank",rel:"noopener noreferrer"}},[e._v("a 2-of-2 multisig"),t("OutboundLink")],1),e._v("\nscript, made with with two "),t("code",[e._v("OP_CHECKSIG(VERIFY)")]),e._v("s.")]),e._v(" "),t("p",[e._v("Now, with the context out of the way, we can begin talking about the code!")]),e._v(" "),t("h2",{attrs:{id:"rust-bitcoin"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#rust-bitcoin"}},[e._v("#")]),e._v(" rust-bitcoin")]),e._v(" "),t("p",[e._v("The first dependency I had to update was "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(". Most of the taproot stuff were already merged in "),t("code",[e._v("master")]),e._v(" (altough they hadn't been released yet). One notable missing part was the support for "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0371.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP371")]),t("OutboundLink")],1),e._v(",\nwhich is an extension of "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP174")]),t("OutboundLink")],1),e._v(", aka the "),t("code",[e._v("Partially Signed Bitcoin Transaction")]),e._v(" BIP. This new BIP defines a few new fields that are required to properly handle Taproot transactions.")]),e._v(" "),t("p",[e._v("Luckily most of the work had already been done by "),t("a",{attrs:{href:"https://twitter.com/sanket1729",target:"_blank",rel:"noopener noreferrer"}},[e._v("sanket1729"),t("OutboundLink")],1),e._v(", so I forked his branch and made only few very minor changes, just to expose a structure that I will have to use later which in his code wasn't public.")]),e._v(" "),t("p",[e._v("You can find all the commits mentioned here in "),t("a",{attrs:{href:"https://github.com/afilini/rust-bitcoin/tree/taproot-testing",target:"_blank",rel:"noopener noreferrer"}},[e._v("my rust-bitcoin "),t("code",[e._v("taproot-testing")]),e._v(" branch"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git diff 187234f f830df9\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("diff --git a/src/lib.rs b/src/lib.rs\nindex 87d9c36..d5e5802 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("@@ -54,7 +54,6 @@")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_mut)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(dead_code)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_imports)]\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(missing_docs)]\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_must_use)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(broken_intra_doc_links)]\n")])]),e._v("\ndiff --git a/src/util/taproot.rs b/src/util/taproot.rs\nindex 674eeee..3d56cbc 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/util/taproot.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/util/taproot.rs")]),e._v("\n@@ -440,7 +440,7 @@ impl TaprootBuilder {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("// Internally used structure to represent the node information in taproot tree\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]\n')])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("pub(crate) struct NodeInfo {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("pub struct NodeInfo {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" /// Merkle Hash for this node\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub(crate) hash: sha256::Hash,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" /// information about leaves inside this node\n")])]),e._v("@@ -448,8 +448,12 @@ pub(crate) struct NodeInfo {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("}\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("impl NodeInfo {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn hash(&self) -> &sha256::Hash {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" &self.hash\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Create a new NodeInfo with omitted/hidden info\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn new_hidden(hash: sha256::Hash) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn new_hidden(hash: sha256::Hash) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Self {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" hash: hash,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" leaves: vec![],\n")])]),e._v("@@ -457,7 +461,7 @@ impl NodeInfo {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Create a new leaf with NodeInfo\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn new_leaf_with_ver(script: Script, ver: LeafVersion) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn new_leaf_with_ver(script: Script, ver: LeafVersion) -> Self {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let leaf = LeafInfo::new(script, ver);\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Self {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" hash: leaf.hash(),\n")])]),e._v("@@ -466,7 +470,7 @@ impl NodeInfo {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Combine two NodeInfo's to create a new parent\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn combine(a: Self, b: Self) -> Result {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn combine(a: Self, b: Self) -> Result {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut all_leaves = Vec::with_capacity(a.leaves.len() + b.leaves.len());\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for mut a_leaf in a.leaves {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" a_leaf.merkle_branch.push(b.hash)?; // add hashing partner\n")])]),e._v("\n")])])]),t("p",[e._v("There isn't much to explain here: I disabled the "),t("code",[e._v("missing_docs")]),e._v(" lint so that the compiler wouldn't complain about the new public methods that aren't documented.\nThen, I added a getter for the "),t("code",[e._v("hash")]),e._v(" field of "),t("code",[e._v("NodeInfo")]),e._v(" and made the struct itself and a bunch of methods public.")]),e._v(" "),t("p",[e._v('We will use this structure later to recover the merkle root of a Taproot script tree, given one leaf and the other "hidden" branches.')]),e._v(" "),t("h2",{attrs:{id:"rust-miniscript"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#rust-miniscript"}},[e._v("#")]),e._v(" rust-miniscript")]),e._v(" "),t("p",[e._v("Moving on to "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(': once again, most of the work required to support Taproot had already been done, but this time I was working with very "early" prototype-like code, so I was prepared to\nmake some changes to the code to get it to work how I wanted.')]),e._v(" "),t("p",[e._v("Instead of showing one big diff I will talk about the commits individually, which I think will help making more clear what I was doing.")]),e._v(" "),t("p",[e._v("Once again, you can find all the commits referenced here in "),t("a",{attrs:{href:"https://github.com/afilini/rust-miniscript/tree/taproot",target:"_blank",rel:"noopener noreferrer"}},[e._v("my rust-miniscript "),t("code",[e._v("taproot")]),e._v(" branch"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 34cf15b\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 34cf15b3aac1d8c2693af1b9749b888f3f29e510\nAuthor: Alekos Filini \nDate: Fri Nov 12 12:06:35 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Fix TapTree iter depth\n")])]),e._v("\ndiff --git a/src/descriptor/tr.rs b/src/descriptor/tr.rs\nindex 79d3c05..314c7f4 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/tr.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/tr.rs")]),e._v("\n@@ -65,7 +65,7 @@ impl TapTree {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" /// Iterate over all miniscripts\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn iter(&self) -> TapTreeIter {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTreeIter { stack: vec![self] }\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTreeIter { stack: vec![(0, self)] }\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Helper function to translate keys\n")])]),e._v("@@ -262,7 +262,7 @@ pub struct TapTreeIter<'a, Pk: MiniscriptKey>\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("where\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Pk: 'a,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("{\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" stack: Vec<&'a TapTree>,\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" stack: Vec<(usize, &'a TapTree)>,\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("}\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("impl<'a, Pk> Iterator for TapTreeIter<'a, Pk>\n")])]),e._v("@@ -273,13 +273,13 @@ where\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn next(&mut self) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" while !self.stack.is_empty() {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let last = self.stack.pop().expect("Size checked above");\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let (depth, last) = self.stack.pop().expect("Size checked above");\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match &*last {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTree::Tree(l, r) => {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push(&r);\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push(&l);\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push((depth + 1, &r));\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" self.stack.push((depth + 1, &l));\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTree::Leaf(ref ms) => return Some((self.stack.len(), ms)),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" TapTree::Leaf(ref ms) => return Some((depth, ms)),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" None\n")])])])])]),t("p",[t("code",[e._v("TapTreeIterator")]),e._v(" is an iterator that goes through a "),t("code",[e._v("TapTree")]),e._v(" and yields a "),t("code",[e._v("(depth, node)")]),e._v(" pair. This is then fed to "),t("a",{attrs:{href:"https://github.com/afilini/rust-miniscript/blob/taproot/src/descriptor/tr.rs#L183-L189",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("TaprootBuilder")]),t("OutboundLink")],1),e._v(", which returns an error if trying to insert nodes\nin "),t("a",{attrs:{href:"https://github.com/afilini/rust-bitcoin/blob/taproot-testing/src/util/taproot.rs#L403-L405",target:"_blank",rel:"noopener noreferrer"}},[e._v("an order that is not DFS"),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("The way the depth was computed before made the builder always fail for non-trivial trees (i.e. more than 1 node).")]),e._v(" "),t("p",[e._v("Here I decided to play the safe card, and just keep track of the depth explicitly: I think there might be a way to compute the depth just knowing the "),t("code",[e._v("self.stack.len()")]),e._v(" (assuming the tree has a specific structure,\nwhich I'm not sure applies here), but anyway I didn't have much time to think about it and I just went for the \"dumb but idiot-proof\" way which ended up working fine.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show f4a3459\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit f4a3459128e37ca0c2701b8b6da064d4952296ff\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:15:52 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Switch rust-bitcoin rev\n")])]),e._v("\ndiff --git a/Cargo.toml b/Cargo.toml\nindex 12825e8..8240024 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/Cargo.toml")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/Cargo.toml")]),e._v('\n@@ -17,7 +17,7 @@ rand = ["bitcoin/rand"]\n\n'),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("[dependencies]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('# bitcoin = "0.27"\n')])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('bitcoin = {git = "https://github.com/sanket1729/rust-bitcoin", branch = "taproot_psbt"}\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('bitcoin = { git = "https://github.com/afilini/rust-bitcoin.git", branch = "taproot-testing" }\n')])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("[dependencies.serde]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('version = "1.0"\n')])])])])]),t("p",[e._v("Trivial commit, switch to "),t("a",{attrs:{href:"https://github.com/afilini/rust-bitcoin/tree/taproot-testing",target:"_blank",rel:"noopener noreferrer"}},[e._v("my fork of rust-bitcoin"),t("OutboundLink")],1),e._v(" so that I can make changes if necessary.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 0446b16\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 0446b1631cec9f7118d46f0f4c94ccd20de29f94\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:25:18 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Parse x-only keys\n")])]),e._v("\ndiff --git a/src/descriptor/key.rs b/src/descriptor/key.rs\nindex 4108d00..b7f90b5 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/key.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/key.rs")]),e._v("\n@@ -283,9 +283,9 @@ impl FromStr for DescriptorPublicKey {\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn from_str(s: &str) -> Result {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' // A "raw" public key without any origin is the least we accept.\n')])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if s.len() < 66 {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if s.len() < 64 {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" return Err(DescriptorKeyParseError(\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' "Key too short (<66 char), doesn\'t match any format",\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' "Key too short (<64 char), doesn\'t match any format",\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" ));\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n@@ -301,6 +301,14 @@ impl FromStr for DescriptorPublicKey {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" derivation_path,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" wildcard,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }))\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else if key_part.len() == 64 {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // x-only pubkey, prefix it with `02`\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let key = bitcoin::PublicKey::from_str(&format!("02{}", key_part))\n')]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' .map_err(|_| DescriptorKeyParseError("Error while parsing x-only public key"))?;\n')]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Ok(DescriptorPublicKey::SinglePub(DescriptorSinglePub {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" key,\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" origin,\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }))\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if key_part.len() >= 2\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' && !(&key_part[0..2] == "02" || &key_part[0..2] == "03" || &key_part[0..2] == "04")\n')])]),e._v("diff --git a/src/lib.rs b/src/lib.rs\nindex e168b16..3a2335e 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/lib.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("@@ -95,8 +95,6 @@")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(non_snake_case)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_mut)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(dead_code)]\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(unused_imports)]\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("#![deny(missing_docs)]\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("pub extern crate bitcoin;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v('#[cfg(feature = "serde")]\n')])])])])]),t("p",[e._v("This, I'm not really sure of: Taproot uses x-only public keys, which means that the first byte (which is usually a "),t("code",[e._v("03")]),e._v(" or a "),t("code",[e._v("02")]),e._v(") that indicates the parity of the EC point is completely dropped, and it's implicit\nthat the point is even (= "),t("code",[e._v("02")]),e._v("). Check out "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP340")]),t("OutboundLink")],1),e._v(" for a much better explanation.")]),e._v(" "),t("p",[e._v("So here when I find a string that is only 64 characters long I will assume it's an x-only pubkey, and I will parse it as a normal "),t("code",[e._v("bitcoin::PublicKey")]),e._v(" by prefixing it with "),t("code",[e._v("02")]),e._v(".")]),e._v(" "),t("p",[e._v("I guess one alternative could have been to try and parse it as a "),t("code",[e._v("schnorr::PublicKey")]),e._v(' and then "convert" it to a '),t("code",[e._v("ecdsa::PublicKey")]),e._v(" which should be supported, but once again I just wanted to get it done quickly and\nthis worked fine.")]),e._v(" "),t("p",[e._v("I also disabled the "),t("code",[e._v("unused_imports")]),e._v(" and "),t("code",[e._v("missing_docs")]),e._v(" lint so that the compiler wouldn't whine too much.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 87316ff\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 87316fffd06ab3bdf300fd1a958ddaa2789a6696\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:26:01 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Parse `tr()` descriptors\n")])]),e._v("\ndiff --git a/src/descriptor/mod.rs b/src/descriptor/mod.rs\nindex 06d98e1..4190786 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/mod.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/mod.rs")]),e._v("\n@@ -610,6 +610,7 @@ where\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("wpkh", 1) => Descriptor::Wpkh(Wpkh::from_tree(top)?),\n')]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("sh", 1) => Descriptor::Sh(Sh::from_tree(top)?),\n')]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("wsh", 1) => Descriptor::Wsh(Wsh::from_tree(top)?),\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' ("tr", _) => Descriptor::Tr(Tr::from_tree(top)?),\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => Descriptor::Bare(Bare::from_tree(top)?),\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" })\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("diff --git a/src/expression.rs b/src/expression.rs\nindex 1cef614..11a68d3 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/expression.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/expression.rs")]),e._v("\n@@ -100,7 +100,12 @@ impl<'a> Tree<'a> {\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" sl = &sl[n + 1..];\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" loop {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let (arg, new_sl) = Tree::from_slice_helper_round(sl, depth + 1)?;\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let (arg, new_sl) = if sl.contains('{') {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Tree::from_slice_helper_curly(sl, depth + 1)?\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Tree::from_slice_helper_round(sl, depth + 1)?\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" };\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" ret.args.push(arg);\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if new_sl.is_empty() {\n")])])])])]),t("p",[e._v("When trying to parse a descriptor (essentially turning a recursive string of "),t("code",[e._v("operator(args)")]),e._v(" into an abstract tree in memory) use a "),t("em",[e._v("curly-bracket-aware")]),e._v(" parser if there is one in the string.")]),e._v(" "),t("p",[e._v("The code to then build a "),t("code",[e._v("Tr")]),e._v(" struct given an "),t("code",[e._v("expression::Tree")]),e._v(" (and the "),t("code",[e._v("from_slice_helper_curly")]),e._v(" function) were already implemented, so it was just a matter of correctly\nbuilding the abstract tree by parsing curly brackets in descriptors.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 3055cab\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 3055cabef8bd51eda344ce501b03c533fd367b4f\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:26:30 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Fix control block creation when satisfying `Tr`\n")])]),e._v("\ndiff --git a/src/descriptor/tr.rs b/src/descriptor/tr.rs\nindex 314c7f4..8487d56 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/tr.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/tr.rs")]),e._v("\n@@ -571,17 +571,14 @@ impl DescriptorTrait for Tr {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let ver = LeafVersion::default();\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let leaf_script = (ms.encode(), ver);\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let control_block_set = spend_info\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .as_script_map()\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .get(&leaf_script)\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' .expect("Control block must exist in script map for every known leaf");\n')])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // let control_block_set = spend_info\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // .as_script_map()\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // .get(&leaf_script)\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' // .expect("Control block must exist in script map for every known leaf");\n')]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' let control_block = spend_info.control_block(&leaf_script).expect("Control block must exist in script map for every known leaf");\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" wit.push(leaf_script.0.into_bytes()); // Push the leaf script\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // There can be multiple control blocks for a (script, ver) pair\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Find the smallest one amongst those\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let control_block = control_block_set\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .iter()\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .min_by(|x, y| x.as_inner().len().cmp(&y.as_inner().len()))\n")]),t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(' .expect("Atleast one control must exist for a known leaf");\n')])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" wit.push(control_block.serialize());\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Finally, save the minimum\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" min_wit = Some(wit);\n")])]),e._v("\n")])])]),t("p",[e._v("This is where things get more interesting: this section of code builds the witness to satisfy a Taproot descriptor. In case of a script-spend, we need to prove that the script we are using had been committed\ninto the public key of our "),t("code",[e._v("P2TR")]),e._v(' input. We do this by adding a "control block", that contains data about the parity of the key, the leaf version used, and the merkle path from the leaf we are using to spend\nup to the merkle root, which is committed into the public key. Once again, this is explained very well in '),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("BIP341")]),t("OutboundLink")],1),e._v(".")]),e._v(" "),t("p",[e._v("Before my patch the code was only getting the set of merkle paths that could lead from the root to the leaves that contain a given script. For context, the signature of "),t("code",[e._v("TaprootSpendInfo::as_script_map(&self)")]),e._v(" is:")]),e._v(" "),t("div",{staticClass:"language-rust extra-class"},[t("pre",{pre:!0,attrs:{class:"language-rust"}},[t("code",[t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// Access the internal script map")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("pub")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("fn")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token function-definition function"}},[e._v("as_script_map")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("->")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("BTreeMap")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("<")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Script")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("LeafVersion")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("BTreeSet")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("TaprootMerkleBranch")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v(">>")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("{")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("}")]),e._v("\n")])])]),t("p",[e._v('Then the code would look for the "shortest" path to that specific script, as it would save size in the final transaction (leaves that are more "deep" in the tree than others naturally have more hidden branches\nin their path to the root, and thus require a longer control block to reveal them all).')]),e._v(" "),t("p",[e._v("The issue here is that the "),t("code",[e._v("control_block")]),e._v(" variable is then serialized directly into the witness. But this is not a control block, it's just a set of merkle paths! A control block only has "),t("em",[e._v("one")]),e._v(" merkle path, and\nincludes the leaf version and the key parity bit.")]),e._v(" "),t("p",[e._v("Conveniently, the "),t("code",[e._v("TaprootSpendInfo")]),e._v(' struct also has this other method (I\'m including the implementation as well, because it shows that internally it does the same "trick" to find the shortest path):')]),e._v(" "),t("div",{staticClass:"language-rust extra-class"},[t("pre",{pre:!0,attrs:{class:"language-rust"}},[t("code",[t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// Obtain a [`ControlBlock`] for particular script with the given version.")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// Returns [`None`] if the script is not contained in the [`TaprootSpendInfo`]")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("/// If there are multiple ControlBlocks possible, this returns the shortest one.")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("pub")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("fn")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token function-definition function"}},[e._v("control_block")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" script_ver"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Script")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("LeafVersion")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("->")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Option")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("ControlBlock")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v(">")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("{")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("let")]),e._v(" merkle_branch_set "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("=")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),e._v("script_map"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("get")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),e._v("script_ver"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("?")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(";")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token comment"}},[e._v("// Choose the smallest one amongst the multiple script maps")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("let")]),e._v(" smallest "),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("=")]),e._v(" merkle_branch_set\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("iter")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("min_by")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token closure-params"}},[t("span",{pre:!0,attrs:{class:"token closure-punctuation punctuation"}},[e._v("|")]),e._v("x"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v(" y"),t("span",{pre:!0,attrs:{class:"token closure-punctuation punctuation"}},[e._v("|")])]),e._v(" x"),t("span",{pre:!0,attrs:{class:"token number"}},[e._v(".0")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("len")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("cmp")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token operator"}},[e._v("&")]),e._v("y"),t("span",{pre:!0,attrs:{class:"token number"}},[e._v(".0")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("len")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("expect")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[e._v('"Non-empty iterator"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(";")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("Some")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("ControlBlock")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("{")]),e._v("\n internal_key"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),e._v("internal_key"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n output_key_parity"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[e._v("self")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),e._v("output_key_parity"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n leaf_version"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[e._v("LeafVersion")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("::")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("default")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n merkle_branch"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(":")]),e._v(" smallest"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[e._v("clone")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(",")]),e._v("\n "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("}")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v(")")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[e._v("}")]),e._v("\n")])])]),t("p",[e._v("So to fix this code we just have to use that method instead, and we can get it done in one single line!")]),e._v(" "),t("p",[e._v('Instead of removing the old code at the time I only commented it out, because I initially thought I would still have to look for the shortest script myself, and I figured the "sorting" code would come in handy\nlater on.')]),e._v(" "),t("p",[e._v("Also, if you are an acute observer, you might have noticed that there's a bug in this last snippet of code. Feel free to think about it a little bit, then check out the "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin/pull/703",target:"_blank",rel:"noopener noreferrer"}},[e._v("PR"),t("OutboundLink")],1),e._v(" I made\nif you wanna know the answer!")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("git show 35378ad\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 35378ad01a6f2b8161a3f36448b24d031f8aeaec\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:27:14 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Consider key-spend max satisfaction weight\n")])]),e._v("\ndiff --git a/src/descriptor/tr.rs b/src/descriptor/tr.rs\nindex 8487d56..fabf860 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/descriptor/tr.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/descriptor/tr.rs")]),e._v("\n@@ -593,7 +593,7 @@ impl DescriptorTrait for Tr {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn max_satisfaction_weight(&self) -> Result {\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut max_wieght = None;\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut max_wieght = Some(65);\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for (depth, ms) in self.iter_scripts() {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let script_size = ms.script_size();\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let max_sat_elems = match ms.max_satisfaction_witness_elements() {\n")])])])])]),t("p",[e._v("This is a little bug in the code that tries to compute what the maximum satisfaction weight would be for a descriptor. For instance, we use this in BDK to compute how many extra sats of fees we need to pay\nin order to target a given fee rate, assuming the descriptor is satisfied with the worst (larger and most expensive) path.")]),e._v(" "),t("p",[e._v("For Taproot descriptors, it's just a matter of iterating over the leaves in the tree and pick the most expensive one... or is it? This doesn't take into account that Taproot outputs can also be spent with\nkey-spend, which means just pushing a signature to the witness. This signature is 64 bytes long when using the new "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("SIGHASH_DEFAULT")]),t("OutboundLink")],1),e._v(" sighash, or 65 otherwise. Since we are thinking about the maximum satisfaction\nweight, or the worst case possible, we naturally pick the latter.")]),e._v(" "),t("p",[e._v("Note that theoretically you could build a Taproot address \"without\" an available key-path spend (by using an unspendable Schnorr public key), but the code here in rust-miniscript doesn't take that into\naccount, as there's no way that I'm aware of to specificy in a "),t("code",[e._v("tr()")]),e._v(" descriptor that the key is unspendable. So, while theoretically here we should first check whether the key-spend path is available before\naccounting for its weight, in practice this is always true in miniscript so we just use that as our starting worst case and update it later if necessary while iterating the tree leaves.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show b4878f8\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit b4878f816e9ede11d5ed947c06e03aa988e3e26f\nAuthor: Alekos Filini \nDate: Sat Nov 13 14:27:53 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Look for taproot stuff in psbts\n")])]),e._v("\ndiff --git a/src/psbt/mod.rs b/src/psbt/mod.rs\nindex 9a8b17d..42c6ce8 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/psbt/mod.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/psbt/mod.rs")]),e._v("\n@@ -25,13 +25,14 @@ use bitcoin;\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d};\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::secp256k1::{self, Secp256k1};\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::util::psbt::PartiallySignedTransaction as Psbt;\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::util::taproot::TapLeafHash;\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use bitcoin::Script;\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use interpreter;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use miniscript::limits::SEQUENCE_LOCKTIME_DISABLE_FLAG;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use miniscript::satisfy::{After, Older};\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use Satisfier;\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use {BitcoinECSig, Preimage32};\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use {BitcoinECSig, BitcoinSchnorrSig, Preimage32};\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("use {MiniscriptKey, ToPublicKey};\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("mod finalizer;\n")])]),e._v("@@ -231,6 +232,24 @@ impl<'psbt> PsbtInputSatisfier<'psbt> {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("}\n")])]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("impl<'psbt, Pk: MiniscriptKey + ToPublicKey> Satisfier for PsbtInputSatisfier<'psbt> {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn lookup_tap_key_spend_sig(&self) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if let Some((sig, hash_ty)) = self.psbt.inputs[self.index].tap_key_sig {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Some(BitcoinSchnorrSig { sig, hash_ty })\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" None\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn lookup_tap_leaf_script_sig(&self, pk: &Pk, lh: &TapLeafHash) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let pk = pk.to_x_only_pubkey();\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if let Some((sig, hash_ty)) = self.psbt.inputs[self.index].tap_script_sigs.get(&(pk, *lh)) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Some(BitcoinSchnorrSig { sig: *sig, hash_ty: *hash_ty })\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" } else {\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" None\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v("\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" fn lookup_ec_sig(&self, pk: &Pk) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" if let Some(rawsig) = self.psbt.inputs[self.index]\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .partial_sigs\n")])])])])]),t("p",[e._v("This commit implements the Taproot-specific "),t("code",[e._v("Satisfier")]),e._v(" methods on "),t("code",[e._v("PsbtInputSatisfier")]),e._v(". The code to produce a valid witness (i.e. "),t("em",[e._v("satisfy")]),e._v(") a descriptor by looking for Taproot key-spend or script-spend signatures\nis already implemented, so it's just a matter of actually returning those, if they are present in a PSBT.")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 80da0ba\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 80da0ba9b742b2dee23e7302e2f95a6e96b1d6ed\nAuthor: Alekos Filini \nDate: Sat Nov 13 16:54:27 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Iter keys in `MultiA`\n")])]),e._v("\ndiff --git a/src/miniscript/iter.rs b/src/miniscript/iter.rs\nindex 36c4b69..a54a371 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/miniscript/iter.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/miniscript/iter.rs")]),e._v("\n@@ -121,7 +121,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn get_leaf_pk(&self) -> Vec {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match self.node {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkK(ref key) => vec![key.clone()],\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) => keys.clone(),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) | Terminal::MultiA(_, ref keys) => keys.clone(),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => vec![],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("@@ -139,7 +139,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match self.node {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkH(ref hash) => vec![hash.clone()],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkK(ref key) => vec![key.to_pubkeyhash()],\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) => keys.iter().map(Pk::to_pubkeyhash).collect(),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) | Terminal::MultiA(_, ref keys) => keys.iter().map(Pk::to_pubkeyhash).collect(),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => vec![],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("@@ -155,7 +155,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match self.node {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkH(ref hash) => vec![PkPkh::HashedPubkey(hash.clone())],\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::PkK(ref key) => vec![PkPkh::PlainPubkey(key.clone())],\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) => keys\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Terminal::Multi(_, ref keys) | Terminal::MultiA(_, ref keys) => keys\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .into_iter()\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .map(|key| PkPkh::PlainPubkey(key.clone()))\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" .collect(),\n")])]),e._v("@@ -170,7 +170,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" pub fn get_nth_pk(&self, n: usize) -> Option {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match (&self.node, n) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::PkK(ref key), 0) => Some(key.clone()),\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) => keys.get(n).cloned(),\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) | (&Terminal::MultiA(_, ref keys), _) => keys.get(n).cloned(),\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => None,\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")])]),e._v("@@ -186,7 +186,7 @@ impl Miniscript {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match (&self.node, n) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix 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Some(PkPkh::PlainPubkey(key.clone())),\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) => {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" (&Terminal::Multi(_, ref keys), _) | (&Terminal::MultiA(_, ref keys), _) => {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" keys.get(n).map(|key| PkPkh::PlainPubkey(key.clone()))\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" }\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" _ => None,\n")])])])])]),t("p",[e._v("Taproot descriptors add a new miniscript operator called "),t("code",[e._v("multi_a()")]),e._v(" which behaves like "),t("code",[e._v("multi()")]),e._v(" in non-Taproot descriptors, but uses the new "),t("a",{attrs:{href:"https://github.com/bitcoin/bips/blob/master/bip-0342.mediawiki#script-execution",target:"_blank",rel:"noopener noreferrer"}},[t("code",[e._v("OP_CHECKSIGADD")]),t("OutboundLink")],1),e._v(" opcode when serialized in a script.")]),e._v(" "),t("p",[e._v("When this was added, somebody forgot to update the various methods that iterate over the public keys of a descriptor to correctly return the keys contained in "),t("code",[e._v("multi_a()")]),e._v(" - essentially, it was falling back in\nthe default case used by the operators that don't contain any key, but this one does!")]),e._v(" "),t("div",{staticClass:"language- extra-class"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[e._v("$ git show 8b108c5\n")])])]),t("div",{staticClass:"language-diff extra-class"},[t("pre",{pre:!0,attrs:{class:"language-diff"}},[t("code",[e._v("commit 8b108c5c0bf50b66b7220746525742b71f6cd4b4\nAuthor: Alekos Filini \nDate: Sat Nov 13 17:26:53 2021 +0100\n\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Fix witness generation for `MultiA`\n")])]),e._v("\ndiff --git a/src/miniscript/satisfy.rs b/src/miniscript/satisfy.rs\nindex 655436e..ab43707 100644\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("--- a/src/miniscript/satisfy.rs")]),e._v("\n"),t("span",{pre:!0,attrs:{class:"token coord"}},[e._v("+++ b/src/miniscript/satisfy.rs")]),e._v("\n@@ -1264,7 +1264,7 @@ impl Satisfaction {\n"),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" // Collect all available signatures\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut sig_count = 0;\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" let mut sigs = vec![vec![vec![]]; keys.len()];\n")])]),t("span",{pre:!0,attrs:{class:"token deleted-sign deleted"}},[t("span",{pre:!0,attrs:{class:"token prefix deleted"}},[e._v("-")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for (i, pk) in keys.iter().enumerate() {\n")])]),t("span",{pre:!0,attrs:{class:"token inserted-sign inserted"}},[t("span",{pre:!0,attrs:{class:"token prefix inserted"}},[e._v("+")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" for (i, pk) in keys.iter().rev().enumerate() {\n")])]),t("span",{pre:!0,attrs:{class:"token unchanged"}},[t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" match Witness::signature::<_, _, Ctx>(stfr, pk, leaf_hash) {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" Witness::Stack(sig) => {\n")]),t("span",{pre:!0,attrs:{class:"token prefix unchanged"}},[e._v(" ")]),t("span",{pre:!0,attrs:{class:"token line"}},[e._v(" sigs[i] = sig;\n")])])])])]),t("p",[e._v("And finally, the last little fix: the "),t("code",[e._v("multi_a()")]),e._v(" operator is satisfied by pushing to the witness either a signature (if you have one available for that specific public key) or an empty vector. The problem is,\nthey have to be in the right order to match the order of public keys in your Taproot script.")]),e._v(" "),t("p",[e._v("rust-miniscript was pushing them in reverse order, so script validation was always failing for multisigs that had more than 1 key. Adding a "),t("code",[e._v(".rev()")]),e._v(" to the iterator fixed the issue.")]),e._v(" "),t("h2",{attrs:{id:"conclusion"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#conclusion"}},[e._v("#")]),e._v(" Conclusion")]),e._v(" "),t("p",[e._v("And that was it! We now have a fully working "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-bitcoin",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-bitcoin"),t("OutboundLink")],1),e._v(" and "),t("a",{attrs:{href:"https://github.com/rust-bitcoin/rust-miniscript",target:"_blank",rel:"noopener noreferrer"}},[e._v("rust-miniscript"),t("OutboundLink")],1),e._v(" ready for Taproot.")]),e._v(" "),t("p",[e._v("In "),t("a",{attrs:{href:"/blog/2021/12/first-bdk-taproot-tx-look-at-the-code-part-2"}},[e._v("Part 2")]),e._v(" I will go over the code changes in BDK, but I think it's now time for you and I to take a break 😃")])])}),[],!1,null,null,null);t.default=a.exports}}]); \ No newline at end of file diff --git a/assets/js/26.dc515bed.js b/assets/js/26.bf513c9a.js similarity index 99% rename from assets/js/26.dc515bed.js rename to assets/js/26.bf513c9a.js index 56c3e65872..f00bf003e1 100644 --- a/assets/js/26.dc515bed.js +++ b/assets/js/26.bf513c9a.js @@ -1 +1 @@ -(window.webpackJsonp=window.webpackJsonp||[]).push([[26],{373:function(t,s,e){"use strict";e.r(s);var a=e(7),n=Object(a.a)({},(function(){var t=this,s=t._self._c;return s("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[s("p",[t._v("This is the second part of a two-part blog series in which I talk through the changes made to BDK to make a Taproot transaction. 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"),s("h2",{attrs:{id:"wrap-fallible-methods"}},[s("a",{staticClass:"header-anchor",attrs:{href:"#wrap-fallible-methods"}},[t._v("#")]),t._v(" Wrap Fallible Methods")]),t._v(" "),s("p",[t._v("Many of the methods exposed by a "),s("code",[t._v("Descriptor")]),t._v(' struct used to be infallible: for instance, it was always possible to "encode" a descriptor into a Bitcoin script by calling the '),s("code",[t._v("script_pubkey()")]),t._v(" method.")]),t._v(" "),s("p",[t._v("Unfortunately, taproot descriptors need some extra metadata to do that: they can be computed by calling the "),s("code",[t._v("spend_info()")]),t._v(" method, and they will be cached inside the descriptor, but since it's not guaranteed by the\ncompiler that the method will be called before trying to encode it, the infallible methods had to be changed to return a "),s("code",[t._v("Result")]),t._v(", so that they can fail if the spend info is not present.")]),t._v(" "),s("p",[t._v("In BDK we call the 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The traits we define\nare implemented on the "),s("code",[t._v("DerivedDescriptor")]),t._v(" or "),s("code",[t._v("ExtendedDescriptor")]),t._v(" structs and allow us to quickly get what we need without having to check the descriptor type manually.")]),t._v(" "),s("p",[t._v("Internally, they are essentially large "),s("code",[t._v("match")]),t._v("es that return different things depending on the descriptor variant. 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Keys, descriptors, Electrum endpoints are not stored in the database. This explains why you'll have to specify them every time in the command line. It can be seen more like a cache and can be safely deleted without risking funds.
  • BDK doesn't automatically "monitor" the blockchain, instead there's a sync command that has to be called by the user.
  • When you create a transaction and then sign it, it's not automatically broadcast to the network. There's a broadcast command that does this. Moreover, the command doesn't accept a normal Bitcoin raw transaction, but instead a PSBT. That's because internally transactions are always moved as PSBTs, and again, the broadcast command is just a very thin wrapper over the raw library call.

    • There are probably more of these examples, but hopefully by this point you'll have more or less understood the gist of it. If you are not a developer, some parts of this will feel weird, inefficient, hard -to understand, and that's absolutely normal. Just try to survive through the pain and you'll be rewarded!

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 2:07:17 PM

    +to understand, and that's absolutely normal. Just try to survive through the pain and you'll be rewarded!

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 6:02:03 PM

    ←

    Copyright © 2023 BDK Developers

    - + diff --git a/bdk-cli/index.html b/bdk-cli/index.html index 5c33e6307d..caebd1db82 100644 --- a/bdk-cli/index.html +++ b/bdk-cli/index.html @@ -33,7 +33,7 @@ - + @@ -71,7 +71,7 @@ GitHub (opens new window)

    # BDK-CLI

    The bdk-cli (opens new window) repo has an example interactive shell built using the bdk library called bdk-cli that acts both as a reference implementation of a wallet -and a tool to quickly experiment with descriptors and transactions.

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 2:07:17 PM
    - + diff --git a/bdk-cli/installation/index.html b/bdk-cli/installation/index.html index ff69b10510..70ebea341b 100644 --- a/bdk-cli/installation/index.html +++ b/bdk-cli/installation/index.html @@ -35,7 +35,7 @@ - + @@ -122,7 +122,7 @@ wallet Wallet Operations

    An example command to sync a testnet wallet to a default electrum server looks like this:

    bdk-cli wallet -w example --descriptor "wpkh(tprv8ZgxMBicQKsPexGYyaFwnAsCXCjmz2FaTm6LtesyyihjbQE3gRMfXqQBXKM43DvC1UgRVv1qom1qFxNMSqVAs88qx9PhgFnfGVUdiiDf6j4/0/*)" sync
-

    +

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/bdk-cli/interface/index.html b/bdk-cli/interface/index.html index 8525ffc68a..efd19bcdca 100644 --- a/bdk-cli/interface/index.html +++ b/bdk-cli/interface/index.html @@ -29,7 +29,7 @@ - + @@ -376,7 +376,7 @@ --psbt <BASE64_PSBT> Sets the PSBT to sign --assume_height <HEIGHT> Assume the blockchain has reached a specific height. This affects the transaction finalization, if there are timelocks in the descriptor --trust_witness_utxo <WITNESS> Whether the signer should trust the witness_utxo, if the non_witness_utxo hasn’t been provided -

    Adds to the PSBT all the signatures it can produce with the secrets embedded in the descriptor (xprv or WIF keys). Returns the signed PSBT and, if there are enough item to satisfy the script, also the extracted raw Bitcoin transaction.

    Optionally, the --assume_height option can be specified to let the wallet assume the blockchain has reached a specific height. This affects the finalization of the PSBT which is done right at the end of the signing process: the wallet tries to satisfy the spending condition of each input using the partial signatures collected. In case timelocks are present the wallet needs to know whether or not they have expired. This flag is particularly useful for offline wallets.

    # sync

    This subcommand has no extra flags. It connects to the chosen Electrum server and synchronizes the list of transactions received and available UTXOs.

    +

    Adds to the PSBT all the signatures it can produce with the secrets embedded in the descriptor (xprv or WIF keys). Returns the signed PSBT and, if there are enough item to satisfy the script, also the extracted raw Bitcoin transaction.

    Optionally, the --assume_height option can be specified to let the wallet assume the blockchain has reached a specific height. This affects the finalization of the PSBT which is done right at the end of the signing process: the wallet tries to satisfy the spending condition of each input using the partial signatures collected. In case timelocks are present the wallet needs to know whether or not they have expired. This flag is particularly useful for offline wallets.

    # sync

    This subcommand has no extra flags. It connects to the chosen Electrum server and synchronizes the list of transactions received and available UTXOs.

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/bdk-cli/introduction/index.html b/bdk-cli/introduction/index.html index f12de6d9f7..f7897a4a0a 100644 --- a/bdk-cli/introduction/index.html +++ b/bdk-cli/introduction/index.html @@ -29,7 +29,7 @@ - + @@ -65,7 +65,7 @@ GitHub (opens new window) GitHub - (opens new window)

    # Introduction

    bdk-cli (opens new window) is a lightweight repl (opens new window) wrapper over bdk that comes as a command line application. It is useful for quick testing and prototyping of bdk functionalities.

    This can also be used as an example application to create your own command line bitcoin wallet tool using bdk.

    bdk-cli can interface with all the blockchain backends currently supported by bdk, like rpc, electrum, esplora and compact_filters.

    Check out project documentation (opens new window) for more details.

    The following sections goes into more details on the installation and usage of bdk-cli.

    + (opens new window)

    # Introduction

    bdk-cli (opens new window) is a lightweight repl (opens new window) wrapper over bdk that comes as a command line application. It is useful for quick testing and prototyping of bdk functionalities.

    This can also be used as an example application to create your own command line bitcoin wallet tool using bdk.

    bdk-cli can interface with all the blockchain backends currently supported by bdk, like rpc, electrum, esplora and compact_filters.

    Check out project documentation (opens new window) for more details.

    The following sections goes into more details on the installation and usage of bdk-cli.

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 6:02:03 PM

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/bdk-cli/playground/index.html b/bdk-cli/playground/index.html index 94f7cc888f..e96a11ad54 100644 --- a/bdk-cli/playground/index.html +++ b/bdk-cli/playground/index.html @@ -27,7 +27,7 @@ - + @@ -63,7 +63,7 @@ GitHub (opens new window) GitHub - (opens new window)

    # Playground

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 2:07:17 PM

    + (opens new window)

    # Playground

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 6:02:03 PM

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/bdk-cli/regtest/index.html b/bdk-cli/regtest/index.html index 92a2fbf030..d4bdc7b3df 100644 --- a/bdk-cli/regtest/index.html +++ b/bdk-cli/regtest/index.html @@ -31,7 +31,7 @@ - + @@ -72,7 +72,7 @@

    Just like before, this command will probably take a while to finish.

    Once it's done, assuming you have a regtest bitcoind running in background, you can launch a new terminal and run the following command to actually start electrs:

    electrs --log-filters INFO --timestamp --db-dir /tmp/electrs-db --electrum-rpc-addr="127.0.0.1:50001" --network=regtest --cookie-file=$HOME/.bitcoin/regtest/.cookie

    on macOS you should change the cookie-file to $HOME/Library/Application Support/Bitcoin/regtest/.cookie.

    This will start the Electrum server on port 50001. You can then add the -n regtest -s 127.0.0.1:50001 to the bdk-cli commands to switch to the local regtest.

    # Troubleshooting

    # Stuck with "wait until bitcoind is synced (i.e. initialblockdownload = false)"

    Just generate a few blocks with bitcoin-cli generatetoaddress 1 <address>

    # Bonus: Docker

    If you have already installed Docker on your machine, you can also use 🍣 Nigiri CLI (opens new window) to spin-up a complete development environment in regtest that includes a bitcoin node, an electrs explorer and the esplora (opens new window) web-app to visualize blocks and transactions in the browser.

    Install 🍣 Nigiri

    $ curl https://getnigiri.vulpem.com | bash

    Start Docker daemon and run Nigiri box

    $ nigiri start
-

    This will start electrum RPC interface on port 51401, the REST interface on 3000 and the esplora UI on 5000 (You can visit with the browser and look for blocks, addresses and transactions)

    You can then add the -n regtest -s 127.0.0.1:51401 to the bdk-cli commands to switch to the local regtest.

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 2:07:17 PM

    +

    This will start electrum RPC interface on port 51401, the REST interface on 3000 and the esplora UI on 5000 (You can visit with the browser and look for blocks, addresses and transactions)

    You can then add the -n regtest -s 127.0.0.1:51401 to the bdk-cli commands to switch to the local regtest.

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 6:02:03 PM

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/2020/12/hello-world/index.html b/blog/2020/12/hello-world/index.html index eb7660abb8..5e0a04f74a 100644 --- a/blog/2020/12/hello-world/index.html +++ b/blog/2020/12/hello-world/index.html @@ -30,7 +30,7 @@ - + @@ -148,7 +148,7 @@ txid = txid );

    # Custom Database and Blockchain types

    We briefly mentioned before that for our example we used the MemoryDatabase, but that it could also be swapped for a different one: this is one example of the modularity of BDK. By default, some database types are already implemented in the library, namely the MemoryDatabase (opens new window) which only keeps data in RAM, the Sled (opens new window) database that can store data on a filesystem, and the SqliteDatabase (opens new window) that can store data into a SQLite database. But since the Database trait is public, users of the library can also implement different database types more suitable for their use-case.

    The same is true for the Blockchain types: the library provides (through the use of opt-in features) implementations for the Electrum, Esplora, CompactFilters (Neutrino) and Bitcoin Core rpc backends. Those again can also be -swapped with custom types if the user desires to do so.

    # Conclusion

    Hopefully, this article will help you get started with BDK! This is just a very quick and gentle introduction to the library, and only barely scratches the surface of what's inside: we will keep publishing more articles in the future to explain some of the more advanced features of BDK, like key generation, using complex descriptors with multiple keys and/or timelocks, using external signers, etc.

    If you'd like to learn more about the library feel free to ask any questions in the comment section down below, or join our Discord Community (opens new window) to chat with us directly!

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 2:07:17 PM

    +swapped with custom types if the user desires to do so.

    # Conclusion

    Hopefully, this article will help you get started with BDK! This is just a very quick and gentle introduction to the library, and only barely scratches the surface of what's inside: we will keep publishing more articles in the future to explain some of the more advanced features of BDK, like key generation, using complex descriptors with multiple keys and/or timelocks, using external signers, etc.

    If you'd like to learn more about the library feel free to ask any questions in the comment section down below, or join our Discord Community (opens new window) to chat with us directly!

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 6:02:03 PM

    BDK wallet with Bitcoin core RPC → @@ -171,6 +171,6 @@

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/2020/12/release-v0.2.0/index.html b/blog/2020/12/release-v0.2.0/index.html index 29ba2c7cc8..d83ccf9caa 100644 --- a/blog/2020/12/release-v0.2.0/index.html +++ b/blog/2020/12/release-v0.2.0/index.html @@ -30,7 +30,7 @@ - + @@ -140,7 +140,7 @@ .map_err(|e| KeyError::Message(e.to_string()))?) } } -

    # Support for sortedmulti()

    Thanks to the addition of sortedmulti() in rust-miniscript, we can now also support them in BDK, which means we are getting more and more compatible with other descriptor-based wallets out there like Bitcoin Core.

    # Contributors

    A huge thanks to everybody who contributed to this new release with suggestions, pull requests and bug reports.

    Since the 0.1.0-beta.1 release over three months ago, we've had 213 new commits made by 10 different contributors for a total of 9990 additions and 2993 deletions. Here's the full diff (opens new window).

    A special thanks to the 7 new contributors:

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 2:07:17 PM
    - + diff --git a/blog/2021/01/fee-estimation-for-light-clients-part-1/index.html b/blog/2021/01/fee-estimation-for-light-clients-part-1/index.html index 212ac5d503..e539f00574 100644 --- a/blog/2021/01/fee-estimation-for-light-clients-part-1/index.html +++ b/blog/2021/01/fee-estimation-for-light-clients-part-1/index.html @@ -30,7 +30,7 @@ - + @@ -86,7 +86,7 @@ fee rate paid by t was the exact value required to get confirmed within the next 6 blocks.

    So to build our model, we first need to gather these data, and machine learning needs a lot of data to work well.

    # The data logger

    The data logger (opens new window) is built with the purpose of collecting all the data we need, and it's MIT licensed open source software written in Rust.

    We need to register the moment in time when transactions enter in the node's mempool; to be efficient and precise we should not only call the RPC endpoints but listen to ZMQ (opens new window) events. Luckily, the just released bitcoin core 0.21.0 added a new ZMQ (opens new window) topic zmqpubsequence notifying mempool events (and block events). The logger is also listening to zmqpubrawtx and zmqpubrawblock topics, to make less RPC calls.

    We are not only interested in the timestamp of the transaction entering the mempool, but also how many blocks it will take until the same transaction is confirmed. In the final dataset this field is called confirms_in[4]; if confirms_in = 1 it means the transaction is confirmed in the first block created after it has been seen for the first time.

    Another critical piece of information logged by the data logger is the fee_rate of the transaction, since the absolute fee value paid by a bitcoin transaction is not available nor derivable given only the transaction itself, as the inputs don't have explicit amounts.

    All these data (apart from the time of the transaction entering in the mempool) can actually be reconstructed simply by looking at the blockchain. However, querying the bitcoin node can be fairly slow, and during the model training iterations we want to recreate the ML dataset rapidly[5], for example whenever we need to modify or add a new field.

    For these reasons, the logger is split into two parts: a process listening to the events sent by our node, which creates raw logs, and then a second process that uses these logs to create the final CSV dataset. Raw logs are self-contained: for example, they contain all the previous transaction output values for every relevant transaction. This causes some redundancy, but in this case it's better to trade some efficiency for more performance -when recreating the dataset.

    High level graph

    My logger instance started collecting data on the 18th of December 2020, and as of today (25th January 2020), the raw logs are about 16GB.

    I expect (or at least hope) the raw logs, the CSV dataset, or the data logger will be useful also for other projects as well, like monitoring the propagation of transactions or other works involving raw mempool data. We will share raw logs data through torrent soon.

    In the following Part 2 we are going to talk about the dataset.

    1. The transaction fee rate is the ratio between the absolute fee expressed in satoshi, over the weight of the transaction measured in virtual bytes. The weight of the transaction is similar to the byte size, however a part of the transaction (the segwit part) is discounted, their byte size is considered less because it creates less burden for the network. ↩︎

    2. mempool is the set of transactions that are valid by consensus rules (for example, they are spending existing bitcoin), broadcasted in the bitcoin peer to peer network, but they are not yet part of the blockchain. ↩︎

    3. DISCLAIMER: I am not an expert data-scientist! ↩︎

    4. Conceptually similar to bitcoin core estimatesmartfee parameter called "blocks target", however, confirms_in is the real value not the desired target. ↩︎

    5. 16GB of compressed raw logs are processed and a compressed CSV produced in about 5 minutes. ↩︎

    - + diff --git a/blog/author/index.html b/blog/author/index.html index eb715441a1..cc9d6cd6c1 100644 --- a/blog/author/index.html +++ b/blog/author/index.html @@ -25,7 +25,7 @@ - + @@ -61,7 +61,7 @@ GitHub (opens new window) GitHub - (opens new window)

    Authors

    - + diff --git a/blog/author/thunderbiscuit/index.html b/blog/author/thunderbiscuit/index.html index 9a4e0693bc..3857373fd2 100644 --- a/blog/author/thunderbiscuit/index.html +++ b/blog/author/thunderbiscuit/index.html @@ -25,7 +25,7 @@ - + @@ -102,6 +102,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/author/waterst0ne/index.html b/blog/author/waterst0ne/index.html index 457073da21..ee3a0d4457 100644 --- a/blog/author/waterst0ne/index.html +++ b/blog/author/waterst0ne/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/author/waterstone/index.html b/blog/author/waterstone/index.html index d12510ef10..af014d3188 100644 --- a/blog/author/waterstone/index.html +++ b/blog/author/waterstone/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/bdk-core-pt1/index.html b/blog/bdk-core-pt1/index.html index 49aa7d0563..c5379a9183 100644 --- a/blog/bdk-core-pt1/index.html +++ b/blog/bdk-core-pt1/index.html @@ -30,7 +30,7 @@ - + @@ -257,7 +257,7 @@ } }

    # Feedback

    The best way to give feedback on this would be to comment on the pull request (opens new window) for this blog post. -Thanks in advance.

    - + diff --git a/blog/tags/Development/index.html b/blog/tags/Development/index.html index 3140cc8d69..a6655576c7 100644 --- a/blog/tags/Development/index.html +++ b/blog/tags/Development/index.html @@ -25,7 +25,7 @@ - + @@ -113,6 +113,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/Flutter/index.html b/blog/tags/Flutter/index.html index 9ab07a0e8c..ec9836fb69 100644 --- a/blog/tags/Flutter/index.html +++ b/blog/tags/Flutter/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/Hardware Wallets/index.html b/blog/tags/Hardware Wallets/index.html index 8904011ec5..546cea554f 100644 --- a/blog/tags/Hardware Wallets/index.html +++ b/blog/tags/Hardware Wallets/index.html @@ -25,7 +25,7 @@ - + @@ -102,6 +102,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/Neutrino/index.html b/blog/tags/Neutrino/index.html index f53de964d9..4035f60c59 100644 --- a/blog/tags/Neutrino/index.html +++ b/blog/tags/Neutrino/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/RPC/index.html b/blog/tags/RPC/index.html index 0c97fc4a2f..eb87e0960c 100644 --- a/blog/tags/RPC/index.html +++ b/blog/tags/RPC/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/React Native/index.html b/blog/tags/React Native/index.html index 49fbe94f3e..1bc710d10a 100644 --- a/blog/tags/React Native/index.html +++ b/blog/tags/React Native/index.html @@ -25,7 +25,7 @@ - + @@ -102,6 +102,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/Wallet/index.html b/blog/tags/Wallet/index.html index 246601ef79..e366c99f3d 100644 --- a/blog/tags/Wallet/index.html +++ b/blog/tags/Wallet/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/architecture/index.html b/blog/tags/architecture/index.html index b57b495571..49f8d8cd11 100644 --- a/blog/tags/architecture/index.html +++ b/blog/tags/architecture/index.html @@ -3,7 +3,7 @@ - Architecture | Bitcoin Dev Kit Documentation + architecture | Bitcoin Dev Kit Documentation @@ -15,9 +15,9 @@ - + - + @@ -25,7 +25,7 @@ - + @@ -61,18 +61,29 @@ GitHub (opens new window) GitHub - (opens new window)

    Posts tagged with Architecture

    bdk-rn: Behind the scenes

    + (opens new window)

    Posts tagged with Architecture

    The Road to BDK 1.0

    By - Bitcoin Zavior + Alekos Filini on - 7/11/2022 + 10/4/2022 - Tags: - BDK-RN, Development, Architecture

    - + diff --git a/blog/tags/basics/index.html b/blog/tags/basics/index.html index 36a48d7a99..f3dab01309 100644 --- a/blog/tags/basics/index.html +++ b/blog/tags/basics/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/bdk-cli/index.html b/blog/tags/bdk-cli/index.html index a288c72088..26944c8539 100644 --- a/blog/tags/bdk-cli/index.html +++ b/blog/tags/bdk-cli/index.html @@ -25,7 +25,7 @@ - + @@ -124,6 +124,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/bdk-rn/index.html b/blog/tags/bdk-rn/index.html index 2b67360729..8715b2bf51 100644 --- a/blog/tags/bdk-rn/index.html +++ b/blog/tags/bdk-rn/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/bdk/index.html b/blog/tags/bdk/index.html index 1b03962cdd..8c0de6549a 100644 --- a/blog/tags/bdk/index.html +++ b/blog/tags/bdk/index.html @@ -25,7 +25,7 @@ - + @@ -168,6 +168,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/bindings/index.html b/blog/tags/bindings/index.html index 35ad874acb..edfa936669 100644 --- a/blog/tags/bindings/index.html +++ b/blog/tags/bindings/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/bitcoin-cli/index.html b/blog/tags/bitcoin-cli/index.html index d9555a0c61..47d2efbbd2 100644 --- a/blog/tags/bitcoin-cli/index.html +++ b/blog/tags/bitcoin-cli/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/bitcoin/index.html b/blog/tags/bitcoin/index.html index da5b74fffd..698a0206f4 100644 --- a/blog/tags/bitcoin/index.html +++ b/blog/tags/bitcoin/index.html @@ -25,7 +25,7 @@ - + @@ -102,6 +102,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/blockchain/index.html b/blog/tags/blockchain/index.html index 15a101e438..8e1c1ad13d 100644 --- a/blog/tags/blockchain/index.html +++ b/blog/tags/blockchain/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/coin selection/index.html b/blog/tags/coin selection/index.html index 7654f1b7da..2a73e832b9 100644 --- a/blog/tags/coin selection/index.html +++ b/blog/tags/coin selection/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/compact_filters/index.html b/blog/tags/compact_filters/index.html index db484ad253..186172d587 100644 --- a/blog/tags/compact_filters/index.html +++ b/blog/tags/compact_filters/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/descriptor/index.html b/blog/tags/descriptor/index.html index 08b0628226..98d3144b97 100644 --- a/blog/tags/descriptor/index.html +++ b/blog/tags/descriptor/index.html @@ -25,7 +25,7 @@ - + @@ -124,6 +124,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/development/index.html b/blog/tags/development/index.html index d8c2e0b965..cc9bb2dbd8 100644 --- a/blog/tags/development/index.html +++ b/blog/tags/development/index.html @@ -25,7 +25,7 @@ - + @@ -113,6 +113,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/fee/index.html b/blog/tags/fee/index.html index 1ea938216f..f1c53b9011 100644 --- a/blog/tags/fee/index.html +++ b/blog/tags/fee/index.html @@ -25,7 +25,7 @@ - + @@ -113,6 +113,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/getting started/index.html b/blog/tags/getting started/index.html index ca61fd961c..a9a779a962 100644 --- a/blog/tags/getting started/index.html +++ b/blog/tags/getting started/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/guide/index.html b/blog/tags/guide/index.html index da8a6dc8ca..a6e83c1efd 100644 --- a/blog/tags/guide/index.html +++ b/blog/tags/guide/index.html @@ -25,7 +25,7 @@ - + @@ -135,6 +135,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/iOS/index.html b/blog/tags/iOS/index.html index 846e604a09..abfa9f0d49 100644 --- a/blog/tags/iOS/index.html +++ b/blog/tags/iOS/index.html @@ -25,7 +25,7 @@ - + @@ -102,6 +102,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/index.html b/blog/tags/index.html index af1b2eb246..ddce441eb1 100644 --- a/blog/tags/index.html +++ b/blog/tags/index.html @@ -25,7 +25,7 @@ - + @@ -61,7 +61,7 @@ GitHub (opens new window) GitHub - (opens new window)

    Tags

    - + diff --git a/blog/tags/miniscript/index.html b/blog/tags/miniscript/index.html index 6cecdd5a21..62612d9f10 100644 --- a/blog/tags/miniscript/index.html +++ b/blog/tags/miniscript/index.html @@ -25,7 +25,7 @@ - + @@ -124,6 +124,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/mobile/index.html b/blog/tags/mobile/index.html index ae34349b79..43d1d0b556 100644 --- a/blog/tags/mobile/index.html +++ b/blog/tags/mobile/index.html @@ -25,7 +25,7 @@ - + @@ -102,6 +102,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/multi-sig/index.html b/blog/tags/multi-sig/index.html index eef587372a..bcf2a0bed7 100644 --- a/blog/tags/multi-sig/index.html +++ b/blog/tags/multi-sig/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/novice/index.html b/blog/tags/novice/index.html index c401a256ff..70a9115b88 100644 --- a/blog/tags/novice/index.html +++ b/blog/tags/novice/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/paper wallets/index.html b/blog/tags/paper wallets/index.html index 6e59b0ac1b..c7502f9fdc 100644 --- a/blog/tags/paper wallets/index.html +++ b/blog/tags/paper wallets/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/release/index.html b/blog/tags/release/index.html index eda0d8715c..919ebb9047 100644 --- a/blog/tags/release/index.html +++ b/blog/tags/release/index.html @@ -25,7 +25,7 @@ - + @@ -168,6 +168,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/rust/index.html b/blog/tags/rust/index.html index 80c5e8af98..534ef9e249 100644 --- a/blog/tags/rust/index.html +++ b/blog/tags/rust/index.html @@ -25,7 +25,7 @@ - + @@ -179,6 +179,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/security/index.html b/blog/tags/security/index.html index 2eabfc8876..07c8d4d091 100644 --- a/blog/tags/security/index.html +++ b/blog/tags/security/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/summer of bitcoin/index.html b/blog/tags/summer of bitcoin/index.html index d49f83b16a..0c643835bf 100644 --- a/blog/tags/summer of bitcoin/index.html +++ b/blog/tags/summer of bitcoin/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/taproot/index.html b/blog/tags/taproot/index.html index 8f88f73e44..553f0b020d 100644 --- a/blog/tags/taproot/index.html +++ b/blog/tags/taproot/index.html @@ -25,7 +25,7 @@ - + @@ -102,6 +102,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/tor/index.html b/blog/tags/tor/index.html index 1954a05642..5d8d966dd0 100644 --- a/blog/tags/tor/index.html +++ b/blog/tags/tor/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/tutorial/index.html b/blog/tags/tutorial/index.html index 66bc23a286..c778a88520 100644 --- a/blog/tags/tutorial/index.html +++ b/blog/tags/tutorial/index.html @@ -25,7 +25,7 @@ - + @@ -157,6 +157,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/blog/tags/wallet/index.html b/blog/tags/wallet/index.html index 6aa94236c8..4fb29e2546 100644 --- a/blog/tags/wallet/index.html +++ b/blog/tags/wallet/index.html @@ -25,7 +25,7 @@ - + @@ -91,6 +91,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/case-studies/index.html b/case-studies/index.html index 62291db54b..eba2e228fb 100644 --- a/case-studies/index.html +++ b/case-studies/index.html @@ -29,7 +29,7 @@ - + @@ -97,6 +97,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/descriptors/index.html b/descriptors/index.html index ee97bfb370..316d4393c2 100644 --- a/descriptors/index.html +++ b/descriptors/index.html @@ -33,7 +33,7 @@ - + @@ -75,7 +75,7 @@ aims to produce the first "Native Descriptor" Bitcoin library that can be used by developers to build their own "Native Descriptor Wallets" (opens new window).

    # Compatibility Matrix

    Below are some tables to highlight the differences between Bitcoin Core's descriptor support, rust-miniscript's one and BDK's.

    # Key Types

    Key Type BDK rust-miniscript Bitcoin Core
    Hex PublicKey ✓ ✓ ✓
    WIF PrivateKey ✓ ✗ ✓
    Extended Keys (xpub/xprv) ✓ ✗ ✓

    # Script Types (top level)

    Script Type BDK rust-miniscript Bitcoin Core
    pk() ✓ ✓ ✓
    pkh() ✓ ✓ ✓
    wpkh() ✓ ✓ ✓
    sh(wpkh()) ✓ ✓ ✓
    sh() ✓ ✓ ✓
    wsh() ✓ ✓ ✓
    sh(wsh()) ✓ ✓ ✓
    combo() ✗ ✗ ✓
    addr() ✗ ✗ ✓
    raw() ✗ ✗ ✓
    Bare scripts ✓ ✓ ✗

    # Operators

    Operator BDK rust-miniscript Bitcoin Core
    pk() ✓ ✓ ✓
    pkh() ✓ ✓ ✓
    older() ✓ ✓ ✓
    after() ✓ ✓ ✓
    sha256() ✓ ✓ ✓
    hash256() ✓ ✓ ✓
    ripemd160() ✓ ✓ ✓
    hash160() ✓ ✓ ✓
    andor() ✓ ✓ ✓
    and_{v,b,n}() ✓ ✓ ✓
    or_{b,c,d,i}() ✓ ✓ ✓
    multi() ✓ ✓ ✓
    thresh() ✓ ✓ ✓
    sortedmulti() ✓ ✓ ✓

    # Modifiers

    Script Type BDK rust-miniscript Bitcoin Core
    a: ✓ ✓ ✓
    s: ✓ ✓ ✓
    c: ✓ ✓ ✓
    t: ✓ ✓ ✓
    d: ✓ ✓ ✓
    v: ✓ ✓ ✓
    j: ✓ ✓ ✓
    n: ✓ ✓ ✓
    l: ✓ ✓ ✓
    u: ✓ ✓ ✓

    For a more thorough description of these operators and modifiers see Sipa's Miniscript Page (opens new window) and Bitcoin Core's (opens new window).

    # Examples

    Some examples of valid BDK descriptors are:

    Spending Policy Descriptor Address 0 Address 1
    Static P2PKH pkh(cSQPHDBwXGjVzWRqAHm6zfvQhaTuj1f2bFH58h55ghbjtFwvmeXR) mrkwtj5xpYQjHeJe5wsweNjVeTKkvR5fCr mrkwtj5xpYQjHeJe5wsweNjVeTKkvR5fCr
    Static P2PKH, watch-only pkh(02e96fe52ef0e22d2f131dd425ce1893073a3c6ad20e8cac36726393dfb4856a4c) mrkwtj5xpYQjHeJe5wsweNjVeTKkvR5fCr mrkwtj5xpYQjHeJe5wsweNjVeTKkvR5fCr
    P2WSH 2-of-2 with one private key wsh(multi(2,tprv8ZgxMBicQKsPePmENhT9N9yiSfTtDoC1f39P7nNmgEyCB6Nm4Qiv1muq4CykB9jtnQg2VitBrWh8PJU8LHzoGMHTrS2VKBSgAz7Ssjf9S3P/0/*,tpubDBYDcH8P2PedrEN3HxWYJJJMZEdgnrqMsjeKpPNzwe7jmGwk5M3HRdSf5vudAXwrJPfUsfvUPFooKWmz79Lh111U51RNotagXiGNeJe3i6t/1/*)) tb1qqsat6c82fvdy73rfzye8f7nwxcz3xny7t56azl73g95mt3tmzvgs9a8vjs tb1q7sgx6gscgtau57jduend6a8l445ahpk3dt3u5zu58rx5qm27lhkqgfdjdr
    P2WSH-P2SH one key + 10 days timelock sh(wsh(and_v(vc:pk_h(tprv8ZgxMBicQKsPePmENhT9N9yiSfTtDoC1f39P7nNmgEyCB6Nm4Qiv1muq4CykB9jtnQg2VitBrWh8PJU8LHzoGMHTrS2VKBSgAz7Ssjf9S3P/0/*),older(1440)))) 2Mtk2nyS98MCi2P7TkoBGLaJviBy956XxB1 2MuEStKzYhqb5HCFgHz9153tZsL5sVqV5xC

    # Implementation Details

    BDK extends the capabilities of rust-miniscript (opens new window) by introducing the concept of an ExtendedDescriptor: it represents a descriptor that contains one or more "derivable keys" like xpubs or xprvs and can be "derived" from a normal Descriptor by deriving every single one of its keys. It is currently called "StringDescriptor" in the code, because it's implemented as a wrapped miniscript::Descriptor<String>.

    ExtendedDescriptors are derived using a single index instead of a full derivation path: this is because normally most of the path is fixed and can be represented right after the xpub/xprv itself, and only the final index changes for each address. This is what's normally called a DescriptorExtendedKey in the codebase, it is represented with a similar syntax to Bitcoin Core's, such as:

    [d34db33f/44'/0'/0']xpub6ERApfZwUNrhL.......rBGRjaDMzQLcgJvLJuZZvRcEL/0/*
-

    +

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/docs-rs/bdk/nightly/latest/bdk/descriptor/enum.Descriptor.html b/docs-rs/bdk/nightly/latest/bdk/descriptor/enum.Descriptor.html index 4109220463..36c87d05d6 100644 --- a/docs-rs/bdk/nightly/latest/bdk/descriptor/enum.Descriptor.html +++ b/docs-rs/bdk/nightly/latest/bdk/descriptor/enum.Descriptor.html @@ -169,8 +169,8 @@
    Examples
    assert_eq!(result.to_string(), "tr(03cc8a4bc64d897bddc5fbc2f670f7a8ba0b386779106cf1223c6fc5d7cd6fc115)#6qm9h8ym");
    Errors

    This function will return an error if hardened derivation is attempted.

    -

    Trait Implementations§

    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Returns the minimum value (in satoshis) at which an output is broadcastable. -Panics if the descriptor wildcard is hardened. Read more
    Deserialize this value from the given Serde deserializer. Read more
    Formats the value using the given formatter. Read more
    Extract the spending policy
    Run a predicate on every key in the descriptor, returning whether +

    Trait Implementations§

    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Returns the minimum value (in satoshis) at which an output is broadcastable. +Panics if the descriptor wildcard is hardened. Read more
    Deserialize this value from the given Serde deserializer. Read more
    Formats the value using the given formatter. Read more
    Extract the spending policy
    Run a predicate on every key in the descriptor, returning whether the predicate returned true for every key Read more
    Run a predicate on every key in the descriptor, returning whether the predicate returned true for any key Read more
    Converts to this type from the input type.
    Converts to this type from the input type.
    Converts to this type from the input type.
    Converts to this type from the input type.
    Converts to this type from the input type.
    Converts to this type from the input type.
    The associated error which can be returned from parsing.
    Parses a string s to return a value of this type. Read more

    Parse an expression tree into a descriptor.

    Feeds this value into the given Hasher. Read more
    Feeds a slice of this type into the given Hasher. Read more
    Convert the object into an abstract policy
    This method returns an Ordering between self and other. Read more
    Compares and returns the maximum of two values. Read more
    Compares and returns the minimum of two values. Read more
    Restrict a value to a certain interval. Read more
    This method tests for self and other values to be equal, and is used diff --git a/docs-rs/bdk/nightly/latest/bdk/index.html b/docs-rs/bdk/nightly/latest/bdk/index.html index bb4b739494..1d3e51deab 100644 --- a/docs-rs/bdk/nightly/latest/bdk/index.html +++ b/docs-rs/bdk/nightly/latest/bdk/index.html @@ -166,4 +166,4 @@

    Contribution

    submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

    -

    Re-exports

    pub extern crate bitcoin;
    pub extern crate miniscript;
    pub use descriptor::template;
    pub use descriptor::HdKeyPaths;
    pub use wallet::signer;
    pub use wallet::signer::SignOptions;
    pub use wallet::tx_builder::TxBuilder;
    pub use wallet::Wallet;
    pub use bdk_chain as chain;

    Modules

    descriptor
    Descriptors
    keys
    Key formats
    psbt
    Additional functions on the rust-bitcoin PartiallySignedTransaction structure.
    wallet
    Wallet

    Macros

    descriptor
    Macro to write full descriptors with code
    fragment
    Macro to write descriptor fragments with code

    Structs

    FeeRate
    Fee rate
    LocalUtxo
    An unspent output owned by a Wallet.
    WeightedUtxo
    A Utxo with its satisfaction_weight.

    Enums

    Error
    Errors that can be thrown by the Wallet
    KeychainKind
    Types of keychains
    Utxo
    An unspent transaction output (UTXO).

    Traits

    Vbytes
    Trait implemented by types that can be used to measure weight units.

    Functions

    version
    Get the version of BDK at runtime
    \ No newline at end of file +

    Re-exports

    pub extern crate bitcoin;
    pub extern crate miniscript;
    pub use descriptor::template;
    pub use descriptor::HdKeyPaths;
    pub use wallet::signer;
    pub use wallet::signer::SignOptions;
    pub use wallet::tx_builder::TxBuilder;
    pub use wallet::Wallet;
    pub use bdk_chain as chain;

    Modules

    descriptor
    Descriptors
    keys
    Key formats
    psbt
    Additional functions on the rust-bitcoin PartiallySignedTransaction structure.
    wallet
    Wallet

    Macros

    descriptor
    Macro to write full descriptors with code
    fragment
    Macro to write descriptor fragments with code

    Structs

    FeeRate
    Fee rate
    LocalUtxo
    An unspent output owned by a Wallet.
    WeightedUtxo
    A Utxo with its satisfaction_weight.

    Enums

    Error
    Errors that can be thrown by the Wallet
    KeychainKind
    Types of keychains
    Utxo
    An unspent transaction output (UTXO).

    Traits

    Vbytes
    Trait implemented by types that can be used to measure weight units.

    Functions

    version
    Get the version of BDK at runtime
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/bdk/struct.LocalUtxo.html b/docs-rs/bdk/nightly/latest/bdk/struct.LocalUtxo.html index 9b2af526ac..2445292199 100644 --- a/docs-rs/bdk/nightly/latest/bdk/struct.LocalUtxo.html +++ b/docs-rs/bdk/nightly/latest/bdk/struct.LocalUtxo.html @@ -5,14 +5,14 @@ pub keychain: KeychainKind, pub is_spent: bool, pub derivation_index: u32, - pub confirmation_time: ConfirmationTime, + pub confirmation_time: ConfirmationTime, }
    Expand description

    An unspent output owned by a Wallet.

    Fields§

    §outpoint: OutPoint

    Reference to a transaction output

    §txout: TxOut

    Transaction output

    §keychain: KeychainKind

    Type of keychain

    §is_spent: bool

    Whether this UTXO is spent or not

    §derivation_index: u32

    The derivation index for the script pubkey in the wallet

    -
    §confirmation_time: ConfirmationTime

    The confirmation time for transaction containing this utxo

    +
    §confirmation_time: ConfirmationTime

    The confirmation time for transaction containing this utxo

    Trait Implementations§

    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Deserialize this value from the given Serde deserializer. Read more
    Feeds this value into the given Hasher. Read more
    Feeds a slice of this type into the given Hasher. Read more
    This method tests for self and other values to be equal, and is used by ==. Read more
    This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
    Serialize this value into the given Serde serializer. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    diff --git a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Balance.html b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Balance.html index cd7bf99660..ece7cd9644 100644 --- a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Balance.html +++ b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Balance.html @@ -1,5 +1,5 @@ Balance in bdk::wallet - Rust

    Struct bdk::wallet::Balance

    pub struct Balance {
+                    logo

    Balance

    Fields

    Methods

    Trait Implementations

    Auto Trait Implementations

    Blanket Implementations

    In bdk::wallet

    Struct bdk::wallet::Balance

    source · 
    pub struct Balance {
     pub immature: u64,
     pub trusted_pending: u64,
     pub untrusted_pending: u64,
@@ -9,13 +9,13 @@
    §trusted_pending: u64

    Unconfirmed UTXOs generated by a wallet tx

    §untrusted_pending: u64

    Unconfirmed UTXOs received from an external wallet

    §confirmed: u64

    Confirmed and immediately spendable balance

    -

    Implementations§

    Get sum of trusted_pending and confirmed coins.

    +

    Implementations§

    Get sum of trusted_pending and confirmed coins.

    This is the balance you can spend right now that shouldn’t get cancelled via another party double spending it.

    -

    Get the whole balance visible to the wallet.

    -

    Trait Implementations§

    The resulting type after applying the + operator.
    Performs the + operation. Read more
    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Returns the “default value” for a type. Read more
    Deserialize this value from the given Serde deserializer. Read more
    Formats the value using the given formatter. Read more
    This method tests for self and other values to be equal, and is used +

    Get the whole balance visible to the wallet.

    +

    Trait Implementations§

    The resulting type after applying the + operator.
    Performs the + operation. Read more
    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Returns the “default value” for a type. Read more
    Deserialize this value from the given Serde deserializer. Read more
    Formats the value using the given formatter. Read more
    This method tests for self and other values to be equal, and is used by ==. Read more
    This method tests for !=. The default implementation is almost always -sufficient, and should not be overridden without very good reason. Read more
    Serialize this value into the given Serde serializer. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    +sufficient, and should not be overridden without very good reason. Read more
    Serialize this value into the given Serde serializer. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    Calls U::from(self).

    That is, this conversion is whatever the implementation of From<T> for U chooses to do.

    diff --git a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.ChangeSet.html b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.ChangeSet.html index 8bacda372d..fe639045c2 100644 --- a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.ChangeSet.html +++ b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.ChangeSet.html @@ -1,11 +1,11 @@ ChangeSet in bdk::wallet - Rust

    Struct bdk::wallet::ChangeSet

    source · 
    pub struct ChangeSet {
-    pub chain: ChangeSet,
-    pub indexed_tx_graph: ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<KeychainKind>>,
+    pub chain: ChangeSet,
+    pub indexed_tx_graph: ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<KeychainKind>>,
 }
    Expand description

    The changes made to a wallet by applying an Update.

    -

    Fields§

    §chain: ChangeSet

    Changes to the LocalChain.

    -
    §indexed_tx_graph: ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<KeychainKind>>

    Changes to IndexedTxGraph.

    -

    Trait Implementations§

    Append another object of the same type onto self.
    Returns whether the structure is considered empty.
    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Returns the “default value” for a type. Read more
    Deserialize this value from the given Serde deserializer. Read more
    Converts to this type from the input type.
    Converts to this type from the input type.
    This method tests for self and other values to be equal, and is used +

    Fields§

    §chain: ChangeSet

    Changes to the LocalChain.

    +
    §indexed_tx_graph: ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<KeychainKind>>

    Changes to IndexedTxGraph.

    +

    Trait Implementations§

    Append another object of the same type onto self.
    Returns whether the structure is considered empty.
    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Returns the “default value” for a type. Read more
    Deserialize this value from the given Serde deserializer. Read more
    Converts to this type from the input type.
    Converts to this type from the input type.
    This method tests for self and other values to be equal, and is used by ==. Read more
    This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
    Serialize this value into the given Serde serializer. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    Calls U::from(self).

    diff --git a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Update.html b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Update.html index 3cf202fb41..81fb61d216 100644 --- a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Update.html +++ b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Update.html @@ -1,14 +1,14 @@ Update in bdk::wallet - Rust

    Struct bdk::wallet::Update

    source · 
    pub struct Update {
     pub last_active_indices: BTreeMap<KeychainKind, u32>,
-    pub graph: TxGraph<ConfirmationTimeHeightAnchor>,
-    pub chain: Option<Update>,
+    pub graph: TxGraph<ConfirmationTimeHeightAnchor>,
+    pub chain: Option<Update>,
 }
    Expand description

    An update to Wallet.

    -

    It updates [bdk_chain::keychain::KeychainTxOutIndex], [bdk_chain::TxGraph] and [local_chain::LocalChain] atomically.

    +

    It updates bdk_chain::keychain::KeychainTxOutIndex, bdk_chain::TxGraph and local_chain::LocalChain atomically.

    Fields§

    §last_active_indices: BTreeMap<KeychainKind, u32>

    Contains the last active derivation indices per keychain (K), which is used to update the -[KeychainTxOutIndex].

    -
    §graph: TxGraph<ConfirmationTimeHeightAnchor>

    Update for the wallet’s internal [TxGraph].

    -
    §chain: Option<Update>

    Update for the wallet’s internal LocalChain.

    +KeychainTxOutIndex.

    +
    §graph: TxGraph<ConfirmationTimeHeightAnchor>

    Update for the wallet’s internal TxGraph.

    +
    §chain: Option<Update>

    Update for the wallet’s internal LocalChain.

    Trait Implementations§

    Returns a copy of the value. Read more
    Performs copy-assignment from source. Read more
    Formats the value using the given formatter. Read more
    Returns the “default value” for a type. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    Calls U::from(self).

    That is, this conversion is whatever the implementation of diff --git a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Wallet.html b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Wallet.html index acb1a71988..45eb0ba05c 100644 --- a/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Wallet.html +++ b/docs-rs/bdk/nightly/latest/bdk/wallet/struct.Wallet.html @@ -7,14 +7,14 @@

  • signers that can contribute signatures to addresses instantiated from the descriptors.

    • Implementations§

    Creates a wallet that does not persist data.

    -

    Create a wallet from a descriptor (and an optional change_descriptor) and load related +

    Create a wallet from a descriptor (and an optional change_descriptor) and load related transaction data from db.

    Get the Bitcoin network the wallet is using.

    Iterator over all keychains in this wallet

    -

    Return a derived address using the external descriptor, see AddressIndex for +

    Return a derived address using the external descriptor, see AddressIndex for available address index selection strategies. If none of the keys in the descriptor are derivable (i.e. does not end with /*) then the same address will always be returned for any AddressIndex.

    -

    Return a derived address using the internal (change) descriptor.

    +

    Return a derived address using the internal (change) descriptor.

    If the wallet doesn’t have an internal descriptor it will use the external descriptor.

    see AddressIndex for available address index selection strategies. If none of the keys in the descriptor are derivable (i.e. does not end with /*) then the same address will always @@ -23,8 +23,8 @@

    Finds how the wallet derived the script pubkey spk.

    Will only return Some(_) if the wallet has given out the spk.

    Return the list of unspent outputs of this wallet

    -

    Get all the checkpoints the wallet is currently storing indexed by height.

    -

    Returns the latest checkpoint.

    +

    Get all the checkpoints the wallet is currently storing indexed by height.

    +

    Returns the latest checkpoint.

    Returns a iterators of all the script pubkeys for the Internal and Externalvariants inKeychainKind`.

    This is intended to be used when doing a full scan of your addresses (e.g. after restoring from seed words). You pass the BTreeMap of iterators to a blockchain data source (e.g. @@ -35,12 +35,12 @@

    See spks_of_all_keychains for more documentation

    Returns the utxo owned by this wallet corresponding to outpoint if it exists in the wallet’s database.

    -

    Inserts a [TxOut] at [OutPoint] into the wallet’s transaction graph. +

    Inserts a [TxOut] at [OutPoint] into the wallet’s transaction graph. Any inserted TxOuts are not persisted until commit is called.

    This can be used to add a TxOut that the wallet doesn’t own but is used as an input to a [Transaction] passed to the calculate_fee or calculate_fee_rate functions.

    Only insert TxOuts you trust the values for!

    -

    Calculates the fee of a given transaction. Returns 0 if tx is a coinbase transaction.

    +

    Calculates the fee of a given transaction. Returns 0 if tx is a coinbase transaction.

    To calculate the fee for a [Transaction] with inputs not owned by this wallet you must manually insert the TxOut(s) into the tx graph using the insert_txout function.

    Note tx does not have to be in the graph for this to work.

    @@ -50,7 +50,7 @@
    Examples
    let tx = &psbt.clone().extract_tx();
 let fee = wallet.calculate_fee(tx).expect("fee");
    -

    Calculate the FeeRate for a given transaction.

    +

    Calculate the FeeRate for a given transaction.

    To calculate the fee rate for a [Transaction] with inputs not owned by this wallet you must manually insert the TxOut(s) into the tx graph using the insert_txout function.

    Note tx does not have to be in the graph for this to work.

    @@ -71,12 +71,12 @@
    Examples
    let tx = &psbt.clone().extract_tx();
 let (sent, received) = wallet.sent_and_received(tx);
    -

    Get a single transaction from the wallet as a [CanonicalTx] (if the transaction exists).

    +

    Get a single transaction from the wallet as a CanonicalTx (if the transaction exists).

    CanonicalTx contains the full transaction alongside meta-data such as:

      -
    • Blocks that the transaction is Anchored in. These may or may not be blocks that exist +
    • Blocks that the transaction is Anchored in. These may or may not be blocks that exist in the best chain.
      • -
    • The [ChainPosition] of the transaction in the best chain - whether the transaction is +
    • The ChainPosition of the transaction in the best chain - whether the transaction is confirmed or unconfirmed. If the transaction is confirmed, the anchor which proves the confirmation is provided. If the transaction is unconfirmed, the unix timestamp of when the transaction was last seen in the mempool is provided.
      • @@ -109,11 +109,11 @@
      Examples
      last_seen, ), }
    -

    Add a new checkpoint to the wallet’s internal view of the chain. +

    Add a new checkpoint to the wallet’s internal view of the chain. This stages but does not commit the change.

    Returns whether anything changed with the insertion (e.g. false if checkpoint was already there).

    -

    Add a transaction to the wallet’s internal view of the chain. This stages but does not +

    Add a transaction to the wallet’s internal view of the chain. This stages but does not commit the change.

    Returns whether anything changed with the transaction insertion (e.g. false if the transaction was already inserted at the same position).

    @@ -123,7 +123,7 @@
    Examples

    WARNING: If position is confirmed, we anchor the tx to a the lowest checkpoint that is >= the position’s height. The caller is responsible for ensuring the tx exists in our local view of the best chain’s history.

    -

    Iterate over the transactions in the wallet.

    +

    Iterate over the transactions in the wallet.

    Return the balance, separated into available, trusted-pending, untrusted-pending and immature values.

    Add an external signer

    @@ -207,17 +207,17 @@
    Example

    get the corresponding PSBT Input for a LocalUtxo

    Return the checksum of the public descriptor associated to keychain

    Internally calls Self::get_descriptor_for_keychain to fetch the right descriptor

    -

    Applies an update to the wallet and stages the changes (but does not commit them).

    +

    Applies an update to the wallet and stages the changes (but does not commit them).

    Usually you create an update by interacting with some blockchain data source and inserting transactions related to your wallet into it.

    -

    Commits all currently staged changed to the persistence backend returning and error when +

    Commits all currently staged changed to the persistence backend returning and error when this fails.

    This returns whether the update resulted in any changes.

    -

    Returns the changes that will be staged with the next call to commit.

    -

    Get a reference to the inner [TxGraph].

    -

    Get a reference to the inner [KeychainTxOutIndex].

    -

    Get a reference to the inner [LocalChain].

    -

    Trait Implementations§

    Converts this type into a shared reference of the (usually inferred) input type.
    Formats the value using the given formatter. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    +

    Returns the changes that will be staged with the next call to commit.

    +

    Get a reference to the inner TxGraph.

    +

    Get a reference to the inner KeychainTxOutIndex.

    +

    Get a reference to the inner LocalChain.

    +

    Trait Implementations§

    Converts this type into a shared reference of the (usually inferred) input type.
    Formats the value using the given formatter. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    Calls U::from(self).

    That is, this conversion is whatever the implementation of From<T> for U chooses to do.

    diff --git a/docs-rs/bdk/nightly/latest/bdk/wallet/tx_builder/struct.TxBuilder.html b/docs-rs/bdk/nightly/latest/bdk/wallet/tx_builder/struct.TxBuilder.html index 1ff7c146a4..943f66590b 100644 --- a/docs-rs/bdk/nightly/latest/bdk/wallet/tx_builder/struct.TxBuilder.html +++ b/docs-rs/bdk/nightly/latest/bdk/wallet/tx_builder/struct.TxBuilder.html @@ -174,7 +174,7 @@
    Errors

    Choose the coin selection algorithm

    Overrides the DefaultCoinSelectionAlgorithm.

    Note that this function consumes the builder and returns it so it is usually best to put this as the first call on the builder.

    -

    Finish building the transaction.

    +

    Finish building the transaction.

    Returns the BIP174 “PSBT” and summary details about the transaction.

    Enable signaling RBF

    This will use the default nSequence value of 0xFFFFFFFD.

    diff --git a/docs-rs/bdk/nightly/latest/bdk_bitcoind_rpc/struct.Emitter.html b/docs-rs/bdk/nightly/latest/bdk_bitcoind_rpc/struct.Emitter.html index 65bca599d5..f044ec49d6 100644 --- a/docs-rs/bdk/nightly/latest/bdk_bitcoind_rpc/struct.Emitter.html +++ b/docs-rs/bdk/nightly/latest/bdk_bitcoind_rpc/struct.Emitter.html @@ -2,7 +2,7 @@

    Refer to module-level documentation for more.

    Implementations§

    Construct a new Emitter with the given RPC client and start_height.

    start_height is the block height to start emitting blocks from.

    -

    Construct a new Emitter with the given RPC client and checkpoint.

    +

    Construct a new Emitter with the given RPC client and checkpoint.

    checkpoint is used to find the latest block which is still part of the best chain. The Emitter will emit blocks starting right above this block.

    Emit mempool transactions, alongside their first-seen unix timestamps.

    diff --git a/docs-rs/bdk/nightly/latest/bdk_electrum/index.html b/docs-rs/bdk/nightly/latest/bdk_electrum/index.html index f7bd8f2fe9..3d0e55ac99 100644 --- a/docs-rs/bdk/nightly/latest/bdk_electrum/index.html +++ b/docs-rs/bdk/nightly/latest/bdk_electrum/index.html @@ -1,7 +1,7 @@ -bdk_electrum - Rust

    Crate bdk_electrum

    source ·
    Expand description

    This crate is used for updating structures of the [bdk_chain] crate with data from electrum.

    +bdk_electrum - Rust

    Crate bdk_electrum

    source ·
    Expand description

    This crate is used for updating structures of the bdk_chain crate with data from electrum.

    The star of the show is the ElectrumExt::scan method, which scans for relevant blockchain -data (via electrum) and outputs updates for [bdk_chain] structures as a tuple of form:

    -

    ([bdk_chain::local_chain::Update], RelevantTxids, keychain_update)

    +data (via electrum) and outputs updates for bdk_chain structures as a tuple of form:

    +

    (bdk_chain::local_chain::Update, RelevantTxids, keychain_update)

    An RelevantTxids only includes txids and no full transactions. The caller is responsible for obtaining full transactions before applying. This can be done with these steps:

    @@ -16,4 +16,4 @@

    Refer to bdk_electrum_example for a complete example.

    -

    Re-exports

    pub use bdk_chain;
    pub use electrum_client;

    Structs

    ElectrumUpdate
    Combination of chain and transactions updates from electrum
    RelevantTxids
    Represents updates fetched from an Electrum server, but excludes full transactions.

    Traits

    ElectrumExt
    Trait to extend [Client] functionality.
    \ No newline at end of file +

    Re-exports

    pub use bdk_chain;
    pub use electrum_client;

    Structs

    ElectrumUpdate
    Combination of chain and transactions updates from electrum
    RelevantTxids
    Represents updates fetched from an Electrum server, but excludes full transactions.

    Traits

    ElectrumExt
    Trait to extend [Client] functionality.
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/bdk_electrum/struct.ElectrumUpdate.html b/docs-rs/bdk/nightly/latest/bdk_electrum/struct.ElectrumUpdate.html index 51a9491cdc..d623bccceb 100644 --- a/docs-rs/bdk/nightly/latest/bdk_electrum/struct.ElectrumUpdate.html +++ b/docs-rs/bdk/nightly/latest/bdk_electrum/struct.ElectrumUpdate.html @@ -1,10 +1,10 @@ ElectrumUpdate in bdk_electrum - Rust

    Struct bdk_electrum::ElectrumUpdate

    source · 
    pub struct ElectrumUpdate {
-    pub chain_update: Update,
+    pub chain_update: Update,
     pub relevant_txids: RelevantTxids,
 }
    Expand description

    Combination of chain and transactions updates from electrum

    We have to update the chain and the txids at the same time since we anchor the txids to the same chain tip that we check before and after we gather the txids.

    -

    Fields§

    §chain_update: Update

    Chain update

    +

    Fields§

    §chain_update: Update

    Chain update

    §relevant_txids: RelevantTxids

    Transaction updates from electrum

    Trait Implementations§

    Formats the value using the given formatter. Read more

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    Calls U::from(self).

    diff --git a/docs-rs/bdk/nightly/latest/bdk_electrum/struct.RelevantTxids.html b/docs-rs/bdk/nightly/latest/bdk_electrum/struct.RelevantTxids.html index 05ccb97d4c..b9a25f53b1 100644 --- a/docs-rs/bdk/nightly/latest/bdk_electrum/struct.RelevantTxids.html +++ b/docs-rs/bdk/nightly/latest/bdk_electrum/struct.RelevantTxids.html @@ -1,13 +1,13 @@ RelevantTxids in bdk_electrum - Rust

    Struct bdk_electrum::RelevantTxids

    source · 
    pub struct RelevantTxids(_);
    Expand description

    Represents updates fetched from an Electrum server, but excludes full transactions.

    -

    To provide a complete update to [TxGraph], you’ll need to call Self::missing_full_txs to -determine the full transactions missing from [TxGraph]. Then call Self::into_tx_graph to +

    To provide a complete update to TxGraph, you’ll need to call Self::missing_full_txs to +determine the full transactions missing from TxGraph. Then call Self::into_tx_graph to fetch the full transactions from Electrum and finalize the update.

    -

    Implementations§

    Determine the full transactions that are missing from graph.

    +

    Implementations§

    Determine the full transactions that are missing from graph.

    Refer to RelevantTxids for more details.

    -

    Finalizes the [TxGraph] update by fetching missing txids from the client.

    +

    Finalizes the TxGraph update by fetching missing txids from the client.

    Refer to RelevantTxids for more details.

    -

    Finalizes RelevantTxids with new_txs and anchors of type -[ConfirmationTimeHeightAnchor].

    +

    Finalizes RelevantTxids with new_txs and anchors of type +ConfirmationTimeHeightAnchor.

    Note: The confirmation time might not be precisely correct if there has been a reorg. Electrum’s API intends that we use the merkle proof API, we should change bdk_electrum to use it.

    diff --git a/docs-rs/bdk/nightly/latest/bdk_electrum/trait.ElectrumExt.html b/docs-rs/bdk/nightly/latest/bdk_electrum/trait.ElectrumExt.html index 4da6f4896a..b8e453cde7 100644 --- a/docs-rs/bdk/nightly/latest/bdk_electrum/trait.ElectrumExt.html +++ b/docs-rs/bdk/nightly/latest/bdk_electrum/trait.ElectrumExt.html @@ -1,19 +1,19 @@ ElectrumExt in bdk_electrum - Rust

    Trait bdk_electrum::ElectrumExt

    source · 
    pub trait ElectrumExt {
-    fn scan<K: Ord + Clone>(
            &self,
            prev_tip: Option<CheckPoint>,
            keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, ScriptBuf)>>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            stop_gap: usize,
            batch_size: usize
        ) -> Result<(ElectrumUpdate, BTreeMap<K, u32>), Error>;
+    fn scan<K: Ord + Clone>(
            &self,
            prev_tip: Option<CheckPoint>,
            keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, ScriptBuf)>>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            stop_gap: usize,
            batch_size: usize
        ) -> Result<(ElectrumUpdate, BTreeMap<K, u32>), Error>;
 
-    fn scan_without_keychain(
            &self,
            prev_tip: Option<CheckPoint>,
            misc_spks: impl IntoIterator<Item = ScriptBuf>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            batch_size: usize
        ) -> Result<ElectrumUpdate, Error> { ... }
+    fn scan_without_keychain(
            &self,
            prev_tip: Option<CheckPoint>,
            misc_spks: impl IntoIterator<Item = ScriptBuf>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            batch_size: usize
        ) -> Result<ElectrumUpdate, Error> { ... }
 }
    Expand description

    Trait to extend [Client] functionality.

    -

    Required Methods§

    Scan the blockchain (via electrum) for the data specified and returns updates for -[bdk_chain] data structures.

    +

    Required Methods§

    Scan the blockchain (via electrum) for the data specified and returns updates for +bdk_chain data structures.

    • prev_tip: the most recent blockchain tip present locally
    • keychain_spks: keychains that we want to scan transactions for
      • -
    • txids: transactions for which we want updated [Anchor]s
      • +
    • txids: transactions for which we want updated Anchors
    • outpoints: transactions associated with these outpoints (residing, spending) that we want to included in the update

    The scan for each keychain stops after a gap of stop_gap script pubkeys with no associated transactions. batch_size specifies the max number of script pubkeys to request for in a single batch request.

    -

    Provided Methods§

    Convenience method to call scan without requiring a keychain.

    -

    Implementations on Foreign Types§

    Implementors§

    \ No newline at end of file +

    Provided Methods§

    Convenience method to call scan without requiring a keychain.

    +

    Implementations on Foreign Types§

    Implementors§

    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraAsyncExt.html b/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraAsyncExt.html index a5811c504d..37b1a7744f 100644 --- a/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraAsyncExt.html +++ b/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraAsyncExt.html @@ -1,27 +1,27 @@ EsploraAsyncExt in bdk_esplora - Rust

    Trait bdk_esplora::EsploraAsyncExt

    source · 
    pub trait EsploraAsyncExt {
-    fn update_local_chain<'life0, 'async_trait>(
            &'life0 self,
            local_tip: Option<CheckPoint>,
            request_heights: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = u32> + Send> + Send
        ) -> Pin<Box<dyn Future<Output = Result<Update, Error>> + Send + 'async_trait>>
        where
            Self: 'async_trait,
            'life0: 'async_trait    ;
-    fn scan_txs_with_keychains<'life0, 'async_trait, K>(
            &'life0 self,
            keychain_spks: BTreeMap<K, impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = (u32, ScriptBuf)> + Send> + Send>,
            txids: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = Txid> + Send> + Send,
            outpoints: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = OutPoint> + Send> + Send,
            stop_gap: usize,
            parallel_requests: usize
        ) -> Pin<Box<dyn Future<Output = Result<(TxGraph<ConfirmationTimeHeightAnchor>, BTreeMap<K, u32>), Error>> + Send + 'async_trait>>
        where
            K: 'async_trait + Ord + Clone + Send,
            Self: 'async_trait,
            'life0: 'async_trait    ;
+    fn update_local_chain<'life0, 'async_trait>(
            &'life0 self,
            local_tip: Option<CheckPoint>,
            request_heights: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = u32> + Send> + Send
        ) -> Pin<Box<dyn Future<Output = Result<Update, Error>> + Send + 'async_trait>>
        where
            Self: 'async_trait,
            'life0: 'async_trait    ;
+    fn scan_txs_with_keychains<'life0, 'async_trait, K>(
            &'life0 self,
            keychain_spks: BTreeMap<K, impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = (u32, ScriptBuf)> + Send> + Send>,
            txids: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = Txid> + Send> + Send,
            outpoints: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = OutPoint> + Send> + Send,
            stop_gap: usize,
            parallel_requests: usize
        ) -> Pin<Box<dyn Future<Output = Result<(TxGraph<ConfirmationTimeHeightAnchor>, BTreeMap<K, u32>), Error>> + Send + 'async_trait>>
        where
            K: 'async_trait + Ord + Clone + Send,
            Self: 'async_trait,
            'life0: 'async_trait    ;
 
-    fn scan_txs<'life0, 'async_trait>(
            &'life0 self,
            misc_spks: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = ScriptBuf> + Send> + Send,
            txids: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = Txid> + Send> + Send,
            outpoints: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = OutPoint> + Send> + Send,
            parallel_requests: usize
        ) -> Pin<Box<dyn Future<Output = Result<TxGraph<ConfirmationTimeHeightAnchor>, Error>> + Send + 'async_trait>>
        where
            Self: Sync + 'async_trait,
            'life0: 'async_trait    ,
+    fn scan_txs<'life0, 'async_trait>(
            &'life0 self,
            misc_spks: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = ScriptBuf> + Send> + Send,
            txids: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = Txid> + Send> + Send,
            outpoints: impl 'async_trait + IntoIterator<IntoIter = impl 'async_trait + Iterator<Item = OutPoint> + Send> + Send,
            parallel_requests: usize
        ) -> Pin<Box<dyn Future<Output = Result<TxGraph<ConfirmationTimeHeightAnchor>, Error>> + Send + 'async_trait>>
        where
            Self: Sync + 'async_trait,
            'life0: 'async_trait    ,
     { ... }
 }
    Expand description

    Trait to extend the functionality of [esplora_client::AsyncClient].

    Refer to crate-level documentation for more.

    -

    Required Methods§

    Prepare an LocalChain update with blocks fetched from Esplora.

    +

    Required Methods§

    Prepare an LocalChain update with blocks fetched from Esplora.

      -
    • local_tip is the previous tip of LocalChain::tip.
      • +
    • local_tip is the previous tip of LocalChain::tip.
    • request_heights is the block heights that we are interested in fetching from Esplora.
    -

    The result of this method can be applied to LocalChain::apply_update.

    -

    Scan Esplora for the data specified and return a [TxGraph] and a map of last active +

    The result of this method can be applied to LocalChain::apply_update.

    +

    Scan Esplora for the data specified and return a TxGraph and a map of last active indices.

    • keychain_spks: keychains that we want to scan transactions for
      • -
    • txids: transactions for which we want updated [ConfirmationTimeHeightAnchor]s
      • +
    • txids: transactions for which we want updated ConfirmationTimeHeightAnchors
    • outpoints: transactions associated with these outpoints (residing, spending) that we want to include in the update

    The scan for each keychain stops after a gap of stop_gap script pubkeys with no associated transactions. parallel_requests specifies the max number of HTTP requests to make in parallel.

    -

    Provided Methods§

    Convenience method to call scan_txs_with_keychains without requiring a keychain.

    -

    Implementations on Foreign Types§

    Implementors§

    \ No newline at end of file +

    Provided Methods§

    Convenience method to call scan_txs_with_keychains without requiring a keychain.

    +

    Implementations on Foreign Types§

    Implementors§

    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraExt.html b/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraExt.html index 2d3eb89fa2..785d69c486 100644 --- a/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraExt.html +++ b/docs-rs/bdk/nightly/latest/bdk_esplora/trait.EsploraExt.html @@ -1,26 +1,26 @@ EsploraExt in bdk_esplora - Rust

    Trait bdk_esplora::EsploraExt

    source · 
    pub trait EsploraExt {
-    fn update_local_chain(
            &self,
            local_tip: Option<CheckPoint>,
            request_heights: impl IntoIterator<Item = u32>
        ) -> Result<Update, Error>;
-    fn scan_txs_with_keychains<K: Ord + Clone>(
            &self,
            keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, ScriptBuf)>>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            stop_gap: usize,
            parallel_requests: usize
        ) -> Result<(TxGraph<ConfirmationTimeHeightAnchor>, BTreeMap<K, u32>), Error>;
+    fn update_local_chain(
            &self,
            local_tip: Option<CheckPoint>,
            request_heights: impl IntoIterator<Item = u32>
        ) -> Result<Update, Error>;
+    fn scan_txs_with_keychains<K: Ord + Clone>(
            &self,
            keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, ScriptBuf)>>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            stop_gap: usize,
            parallel_requests: usize
        ) -> Result<(TxGraph<ConfirmationTimeHeightAnchor>, BTreeMap<K, u32>), Error>;
 
-    fn scan_txs(
            &self,
            misc_spks: impl IntoIterator<Item = ScriptBuf>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            parallel_requests: usize
        ) -> Result<TxGraph<ConfirmationTimeHeightAnchor>, Error> { ... }
+    fn scan_txs(
            &self,
            misc_spks: impl IntoIterator<Item = ScriptBuf>,
            txids: impl IntoIterator<Item = Txid>,
            outpoints: impl IntoIterator<Item = OutPoint>,
            parallel_requests: usize
        ) -> Result<TxGraph<ConfirmationTimeHeightAnchor>, Error> { ... }
 }
    Expand description

    Trait to extend the functionality of [esplora_client::BlockingClient].

    Refer to crate-level documentation for more.

    -

    Required Methods§

    Prepare an LocalChain update with blocks fetched from Esplora.

    +

    Required Methods§

    Prepare an LocalChain update with blocks fetched from Esplora.

      -
    • prev_tip is the previous tip of LocalChain::tip.
      • +
    • prev_tip is the previous tip of LocalChain::tip.
    • get_heights is the block heights that we are interested in fetching from Esplora.
    -

    The result of this method can be applied to LocalChain::apply_update.

    -

    Scan Esplora for the data specified and return a [TxGraph] and a map of last active +

    The result of this method can be applied to LocalChain::apply_update.

    +

    Scan Esplora for the data specified and return a TxGraph and a map of last active indices.

    • keychain_spks: keychains that we want to scan transactions for
      • -
    • txids: transactions for which we want updated [ConfirmationTimeHeightAnchor]s
      • +
    • txids: transactions for which we want updated ConfirmationTimeHeightAnchors
    • outpoints: transactions associated with these outpoints (residing, spending) that we want to include in the update

    The scan for each keychain stops after a gap of stop_gap script pubkeys with no associated transactions. parallel_requests specifies the max number of HTTP requests to make in parallel.

    -

    Provided Methods§

    Convenience method to call scan_txs_with_keychains without requiring a keychain.

    -

    Implementations on Foreign Types§

    Implementors§

    \ No newline at end of file +

    Provided Methods§

    Convenience method to call scan_txs_with_keychains without requiring a keychain.

    +

    Implementations on Foreign Types§

    Implementors§

    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/bdk_file_store/index.html b/docs-rs/bdk/nightly/latest/bdk_file_store/index.html index de9ea6528c..a8ba16633d 100644 --- a/docs-rs/bdk/nightly/latest/bdk_file_store/index.html +++ b/docs-rs/bdk/nightly/latest/bdk_file_store/index.html @@ -1,6 +1,6 @@ bdk_file_store - Rust

    Crate bdk_file_store

    source ·
    Expand description

    BDK File Store

    This is a simple append-only flat file implementation of -Persist.

    +Persist.

    The main structure is Store, which can be used with bdk’s Wallet to persist wallet data into a flat file.

    Structs

    EntryIter
    Iterator over entries in a file store.
    Store
    Persists an append-only list of changesets (C) to a single file.

    Enums

    FileError
    Error that occurs due to problems encountered with the file.
    IterError
    Error type for EntryIter.
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/bdk_file_store/struct.Store.html b/docs-rs/bdk/nightly/latest/bdk_file_store/struct.Store.html index ecf86c8590..3805e70edb 100644 --- a/docs-rs/bdk/nightly/latest/bdk_file_store/struct.Store.html +++ b/docs-rs/bdk/nightly/latest/bdk_file_store/struct.Store.html @@ -1,6 +1,6 @@ Store in bdk_file_store - Rust

    Struct bdk_file_store::Store

    source · 
    pub struct Store<'a, C> { /* private fields */ }
    Expand description

    Persists an append-only list of changesets (C) to a single file.

    The changesets are the results of altering a tracker implementation (T).

    -

    Implementations§

    Creates a new store from a File.

    +

    Implementations§

    Creates a new store from a File.

    The file must have been opened with read and write permissions.

    magic is the expected prefixed bytes of the file. If this does not match, an error will be returned.

    @@ -27,7 +27,7 @@ changeset.

    The truncation is to avoid the possibility of having a valid but inconsistent changeset directly after the appended changeset.

    -

    Trait Implementations§

    Formats the value using the given formatter. Read more
    The error the backend returns when it fails to write.
    The error the backend returns when it fails to load changesets C.
    Writes a changeset to the persistence backend. Read more
    Return the aggregate changeset C from persistence.

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    +

    Trait Implementations§

    Formats the value using the given formatter. Read more
    The error the backend returns when it fails to write.
    The error the backend returns when it fails to load changesets C.
    Writes a changeset to the persistence backend. Read more
    Return the aggregate changeset C from persistence.

    Auto Trait Implementations§

    Blanket Implementations§

    Gets the TypeId of self. Read more
    Immutably borrows from an owned value. Read more
    Mutably borrows from an owned value. Read more

    Returns the argument unchanged.

    Calls U::from(self).

    That is, this conversion is whatever the implementation of From<T> for U chooses to do.

    diff --git a/docs-rs/bdk/nightly/latest/example_bitcoind_rpc_polling/type.ChangeSet.html b/docs-rs/bdk/nightly/latest/example_bitcoind_rpc_polling/type.ChangeSet.html index 74f57a74be..c650b3daca 100644 --- a/docs-rs/bdk/nightly/latest/example_bitcoind_rpc_polling/type.ChangeSet.html +++ b/docs-rs/bdk/nightly/latest/example_bitcoind_rpc_polling/type.ChangeSet.html @@ -1 +1 @@ -ChangeSet in example_bitcoind_rpc_polling - Rust

    Type Definition example_bitcoind_rpc_polling::ChangeSet

    source · 
    pub(crate) type ChangeSet = (ChangeSet, ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<Keychain>>);
    \ No newline at end of file +ChangeSet in example_bitcoind_rpc_polling - Rust

    Type Definition example_bitcoind_rpc_polling::ChangeSet

    source · 
    pub(crate) type ChangeSet = (ChangeSet, ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<Keychain>>);
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_cli/fn.create_tx.html b/docs-rs/bdk/nightly/latest/example_cli/fn.create_tx.html index 2c2a8155a9..e28a9de141 100644 --- a/docs-rs/bdk/nightly/latest/example_cli/fn.create_tx.html +++ b/docs-rs/bdk/nightly/latest/example_cli/fn.create_tx.html @@ -1 +1 @@ -create_tx in example_cli - Rust

    Function example_cli::create_tx

    source · 
    pub fn create_tx<A: Anchor, O: ChainOracle>(
        graph: &mut KeychainTxGraph<A>,
        chain: &O,
        keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
        cs_algorithm: CoinSelectionAlgo,
        address: Address,
        value: u64
    ) -> Result<(Transaction, Option<(ChangeSet<Keychain>, (Keychain, u32))>)>where
        O::Error: Error + Send + Sync + 'static,
    \ No newline at end of file +create_tx in example_cli - Rust

    Function example_cli::create_tx

    source · 
    pub fn create_tx<A: Anchor, O: ChainOracle>(
        graph: &mut KeychainTxGraph<A>,
        chain: &O,
        keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
        cs_algorithm: CoinSelectionAlgo,
        address: Address,
        value: u64
    ) -> Result<(Transaction, Option<(ChangeSet<Keychain>, (Keychain, u32))>)>where
        O::Error: Error + Send + Sync + 'static,
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_cli/fn.handle_commands.html b/docs-rs/bdk/nightly/latest/example_cli/fn.handle_commands.html index e9d600c2b7..6108d8a84a 100644 --- a/docs-rs/bdk/nightly/latest/example_cli/fn.handle_commands.html +++ b/docs-rs/bdk/nightly/latest/example_cli/fn.handle_commands.html @@ -1 +1 @@ -handle_commands in example_cli - Rust

    Function example_cli::handle_commands

    source · 
    pub fn handle_commands<CS: Subcommand, S: Args, A: Anchor, O: ChainOracle, C>(
        graph: &Mutex<KeychainTxGraph<A>>,
        db: &Mutex<Database<'_, C>>,
        chain: &Mutex<O>,
        keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
        network: Network,
        broadcast: impl FnOnce(S, &Transaction) -> Result<()>,
        cmd: Commands<CS, S>
    ) -> Result<()>where
        O::Error: Error + Send + Sync + 'static,
        C: Default + Append + DeserializeOwned + Serialize + From<KeychainChangeSet<A>>,
    \ No newline at end of file +handle_commands in example_cli - Rust

    Function example_cli::handle_commands

    source · 
    pub fn handle_commands<CS: Subcommand, S: Args, A: Anchor, O: ChainOracle, C>(
        graph: &Mutex<KeychainTxGraph<A>>,
        db: &Mutex<Database<'_, C>>,
        chain: &Mutex<O>,
        keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
        network: Network,
        broadcast: impl FnOnce(S, &Transaction) -> Result<()>,
        cmd: Commands<CS, S>
    ) -> Result<()>where
        O::Error: Error + Send + Sync + 'static,
        C: Default + Append + DeserializeOwned + Serialize + From<KeychainChangeSet<A>>,
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_cli/fn.init.html b/docs-rs/bdk/nightly/latest/example_cli/fn.init.html index 7d16870bf2..68cbb060ec 100644 --- a/docs-rs/bdk/nightly/latest/example_cli/fn.init.html +++ b/docs-rs/bdk/nightly/latest/example_cli/fn.init.html @@ -1 +1 @@ -init in example_cli - Rust

    Function example_cli::init

    source · 
    pub fn init<'m, CS: Subcommand, S: Args, C>(
        db_magic: &'m [u8],
        db_default_path: &str
    ) -> Result<(Args<CS, S>, KeyMap, KeychainTxOutIndex<Keychain>, Mutex<Database<'m, C>>, C)>where
        C: Default + Append + Serialize + DeserializeOwned,
    \ No newline at end of file +init in example_cli - Rust

    Function example_cli::init

    source · 
    pub fn init<'m, CS: Subcommand, S: Args, C>(
        db_magic: &'m [u8],
        db_default_path: &str
    ) -> Result<(Args<CS, S>, KeyMap, KeychainTxOutIndex<Keychain>, Mutex<Database<'m, C>>, C)>where
        C: Default + Append + Serialize + DeserializeOwned,
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_cli/fn.planned_utxos.html b/docs-rs/bdk/nightly/latest/example_cli/fn.planned_utxos.html index bf87a9aa4e..76065cde87 100644 --- a/docs-rs/bdk/nightly/latest/example_cli/fn.planned_utxos.html +++ b/docs-rs/bdk/nightly/latest/example_cli/fn.planned_utxos.html @@ -1 +1 @@ -planned_utxos in example_cli - Rust

    Function example_cli::planned_utxos

    source · 
    pub fn planned_utxos<A: Anchor, O: ChainOracle, K: Clone + CanDerive>(
        graph: &KeychainTxGraph<A>,
        chain: &O,
        assets: &Assets<K>
    ) -> Result<Vec<(Plan<K>, FullTxOut<A>)>, O::Error>
    \ No newline at end of file +planned_utxos in example_cli - Rust

    Function example_cli::planned_utxos

    source · 
    pub fn planned_utxos<A: Anchor, O: ChainOracle, K: Clone + CanDerive>(
        graph: &KeychainTxGraph<A>,
        chain: &O,
        assets: &Assets<K>
    ) -> Result<Vec<(Plan<K>, FullTxOut<A>)>, O::Error>
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_cli/type.Database.html b/docs-rs/bdk/nightly/latest/example_cli/type.Database.html index e95f4fa380..f486b20c1b 100644 --- a/docs-rs/bdk/nightly/latest/example_cli/type.Database.html +++ b/docs-rs/bdk/nightly/latest/example_cli/type.Database.html @@ -1 +1 @@ -Database in example_cli - Rust

    Type Definition example_cli::Database

    source · 
    pub type Database<'m, C> = Persist<Store<'m, C>, C>;
    \ No newline at end of file +Database in example_cli - Rust

    Type Definition example_cli::Database

    source · 
    pub type Database<'m, C> = Persist<Store<'m, C>, C>;
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_cli/type.KeychainChangeSet.html b/docs-rs/bdk/nightly/latest/example_cli/type.KeychainChangeSet.html index 6ad4e05f81..f80a161e8f 100644 --- a/docs-rs/bdk/nightly/latest/example_cli/type.KeychainChangeSet.html +++ b/docs-rs/bdk/nightly/latest/example_cli/type.KeychainChangeSet.html @@ -1 +1 @@ -KeychainChangeSet in example_cli - Rust

    Type Definition example_cli::KeychainChangeSet

    source · 
    pub type KeychainChangeSet<A> = (ChangeSet, ChangeSet<A, ChangeSet<Keychain>>);
    \ No newline at end of file +KeychainChangeSet in example_cli - Rust

    Type Definition example_cli::KeychainChangeSet

    source · 
    pub type KeychainChangeSet<A> = (ChangeSet, ChangeSet<A, ChangeSet<Keychain>>);
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_cli/type.KeychainTxGraph.html b/docs-rs/bdk/nightly/latest/example_cli/type.KeychainTxGraph.html index 9796925320..9537676556 100644 --- a/docs-rs/bdk/nightly/latest/example_cli/type.KeychainTxGraph.html +++ b/docs-rs/bdk/nightly/latest/example_cli/type.KeychainTxGraph.html @@ -1 +1 @@ -KeychainTxGraph in example_cli - Rust

    Type Definition example_cli::KeychainTxGraph

    source · 
    pub type KeychainTxGraph<A> = IndexedTxGraph<A, KeychainTxOutIndex<Keychain>>;
    \ No newline at end of file +KeychainTxGraph in example_cli - Rust

    Type Definition example_cli::KeychainTxGraph

    source · 
    pub type KeychainTxGraph<A> = IndexedTxGraph<A, KeychainTxOutIndex<Keychain>>;
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_electrum/type.ChangeSet.html b/docs-rs/bdk/nightly/latest/example_electrum/type.ChangeSet.html index e4f850fe8f..e65eaa0923 100644 --- a/docs-rs/bdk/nightly/latest/example_electrum/type.ChangeSet.html +++ b/docs-rs/bdk/nightly/latest/example_electrum/type.ChangeSet.html @@ -1 +1 @@ -ChangeSet in example_electrum - Rust

    Type Definition example_electrum::ChangeSet

    source · 
    pub(crate) type ChangeSet = (ChangeSet, ChangeSet<ConfirmationHeightAnchor, ChangeSet<Keychain>>);
    \ No newline at end of file +ChangeSet in example_electrum - Rust

    Type Definition example_electrum::ChangeSet

    source · 
    pub(crate) type ChangeSet = (ChangeSet, ChangeSet<ConfirmationHeightAnchor, ChangeSet<Keychain>>);
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/example_esplora/type.ChangeSet.html b/docs-rs/bdk/nightly/latest/example_esplora/type.ChangeSet.html index 17a9a772b4..b687a49edc 100644 --- a/docs-rs/bdk/nightly/latest/example_esplora/type.ChangeSet.html +++ b/docs-rs/bdk/nightly/latest/example_esplora/type.ChangeSet.html @@ -1 +1 @@ -ChangeSet in example_esplora - Rust

    Type Definition example_esplora::ChangeSet

    source · 
    pub(crate) type ChangeSet = (ChangeSet, ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<Keychain>>);
    \ No newline at end of file +ChangeSet in example_esplora - Rust

    Type Definition example_esplora::ChangeSet

    source · 
    pub(crate) type ChangeSet = (ChangeSet, ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<Keychain>>);
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/help.html b/docs-rs/bdk/nightly/latest/help.html index 8659dfcc0d..01a55467d8 100644 --- a/docs-rs/bdk/nightly/latest/help.html +++ b/docs-rs/bdk/nightly/latest/help.html @@ -1 +1 @@ -Rustdoc help

    Rustdoc help

    Back
    \ No newline at end of file +Rustdoc help

    Rustdoc help

    Back
    \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/implementors/bdk_chain/persist/trait.PersistBackend.js b/docs-rs/bdk/nightly/latest/implementors/bdk_chain/persist/trait.PersistBackend.js index 4fcc8ceda6..f098b6e1ab 100644 --- a/docs-rs/bdk/nightly/latest/implementors/bdk_chain/persist/trait.PersistBackend.js +++ b/docs-rs/bdk/nightly/latest/implementors/bdk_chain/persist/trait.PersistBackend.js @@ -1,4 +1,4 @@ (function() {var implementors = { "bdk_chain":[], -"bdk_file_store":[["impl<'a, C> PersistBackend<C> for Store<'a, C>where
        C: Default + Append + Serialize + DeserializeOwned,    "]] +"bdk_file_store":[["impl<'a, C> PersistBackend<C> for Store<'a, C>where
        C: Default + Append + Serialize + DeserializeOwned,    "]] };if (window.register_implementors) {window.register_implementors(implementors);} else {window.pending_implementors = implementors;}})() \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/implementors/bdk_chain/tx_data_traits/trait.Append.js b/docs-rs/bdk/nightly/latest/implementors/bdk_chain/tx_data_traits/trait.Append.js index 2b650fa85a..7b3d82a242 100644 --- a/docs-rs/bdk/nightly/latest/implementors/bdk_chain/tx_data_traits/trait.Append.js +++ b/docs-rs/bdk/nightly/latest/implementors/bdk_chain/tx_data_traits/trait.Append.js @@ -1,4 +1,4 @@ (function() {var implementors = { -"bdk":[["impl Append for ChangeSet"]], +"bdk":[["impl Append for ChangeSet"]], "bdk_chain":[] };if (window.register_implementors) {window.register_implementors(implementors);} else {window.pending_implementors = implementors;}})() \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.AsRef.js b/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.AsRef.js index 8528302c07..10305d41fc 100644 --- a/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.AsRef.js +++ b/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.AsRef.js @@ -1,4 +1,4 @@ (function() {var implementors = { -"bdk":[["impl AsRef<[u8]> for KeychainKind"],["impl<D> AsRef<TxGraph<ConfirmationTimeHeightAnchor>> for Wallet<D>"]], +"bdk":[["impl AsRef<[u8]> for KeychainKind"],["impl<D> AsRef<TxGraph<ConfirmationTimeHeightAnchor>> for Wallet<D>"]], "bdk_chain":[["impl<K> AsRef<BTreeMap<K, u32, Global>> for ChangeSet<K>"],["impl<A> AsRef<TxGraph<A>> for TxGraph<A>"]] };if (window.register_implementors) {window.register_implementors(implementors);} else {window.pending_implementors = implementors;}})() \ No newline at end of file diff --git a/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.From.js b/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.From.js index 9aa38da263..150767d4bb 100644 --- a/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.From.js +++ b/docs-rs/bdk/nightly/latest/implementors/core/convert/trait.From.js @@ -1,5 +1,5 @@ (function() {var implementors = { -"bdk":[["impl From<Error> for Error"],["impl From<PolicyError> for Error"],["impl From<SignerError> for Error"],["impl From<KeyError> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<KeyError> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<PolicyError> for Error"],["impl From<bool> for Satisfaction"],["impl From<SatisfiableItem> for Policy"],["impl<Ctx: ScriptContext> From<ExtendedPubKey> for ExtendedKey<Ctx>"],["impl<Ctx: ScriptContext> From<ExtendedPrivKey> for ExtendedKey<Ctx>"],["impl From<Error> for KeyError"],["impl From<Error> for KeyError"],["impl From<Hash> for SignerId"],["impl From<Fingerprint> for SignerId"],["impl From<Error> for SignerError"],["impl From<BTreeMap<u32, Option<BlockHash>, Global>> for ChangeSet"],["impl From<ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<KeychainKind>>> for ChangeSet"]], +"bdk":[["impl From<Error> for Error"],["impl From<PolicyError> for Error"],["impl From<SignerError> for Error"],["impl From<KeyError> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<KeyError> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<Error> for Error"],["impl From<PolicyError> for Error"],["impl From<bool> for Satisfaction"],["impl From<SatisfiableItem> for Policy"],["impl<Ctx: ScriptContext> From<ExtendedPubKey> for ExtendedKey<Ctx>"],["impl<Ctx: ScriptContext> From<ExtendedPrivKey> for ExtendedKey<Ctx>"],["impl From<Error> for KeyError"],["impl From<Error> for KeyError"],["impl From<Hash> for SignerId"],["impl From<Fingerprint> for SignerId"],["impl From<Error> for SignerError"],["impl From<BTreeMap<u32, Option<BlockHash>, Global>> for ChangeSet"],["impl From<ChangeSet<ConfirmationTimeHeightAnchor, ChangeSet<KeychainKind>>> for ChangeSet"]], "bdk_chain":[["impl From<ChainPosition<ConfirmationTimeHeightAnchor>> for ConfirmationTime"],["impl From<(u32, BlockHash)> for BlockId"],["impl From<BlockId> for (u32, BlockHash)"],["impl From<(&u32, &BlockHash)> for BlockId"],["impl<A, IA: Default> From<ChangeSet<A>> for ChangeSet<A, IA>"],["impl<A, K> From<ChangeSet<K>> for ChangeSet<A, ChangeSet<K>>"],["impl From<LocalChain> for BTreeMap<u32, BlockHash>"],["impl From<BTreeMap<u32, BlockHash, Global>> for LocalChain"]], "bdk_coin_select":[["impl From<usize> for BnbLimit"],["impl From<Duration> for BnbLimit"]], "bdk_file_store":[["impl From<Error> for IterError"],["impl<'a> From<Error> for FileError<'a>"]], diff --git a/docs-rs/bdk/nightly/latest/settings.html b/docs-rs/bdk/nightly/latest/settings.html index 84a9af5c58..dcd0579fb8 100644 --- a/docs-rs/bdk/nightly/latest/settings.html +++ b/docs-rs/bdk/nightly/latest/settings.html @@ -1 +1 @@ -Rustdoc settings

    Rustdoc settings

    Back
    \ No newline at end of file +Rustdoc settings

    Rustdoc settings

    Back
    \ No newline at end of file diff --git a/examples/index.html b/examples/index.html index f2a03ae80a..b2ae9cabcf 100644 --- a/examples/index.html +++ b/examples/index.html @@ -29,7 +29,7 @@ - + @@ -65,7 +65,7 @@ GitHub (opens new window)
    GitHub - (opens new window)

    # Examples

    Click the links below and learn from community-built example projects.

    # BDK-CLI (opens new window)

    A command line interface to experiment with the bitcoindevkit.

    # DevkitWallet (opens new window)

    A demo app for the bitcoindevkit on Android using bdk-kotlin.

    # Padawan Wallet (opens new window)

    A testnet-only bitcoin wallet full of tutorials on how to use bitcoin wallets.

    # BDKSwiftExampleWallet (opens new window)

    An example iOS app using bdk-swift.

    # Tatooine (opens new window)

    Tatooine is a small bitcoin testnet faucet built with Ktor, a Kotlin asynchronous framework for creating microservices and web applications.

    # SEBA Bank Proof of reserves (opens new window)

    The bdk library aims to be the core building block for Bitcoin wallets of any kind. The bdk-reserves library provides an implementation of proof-of-reserves for bdk.

    # Stackmate (opens new window)

    A multi-purpose Bitcoin Wallet.

    # Spotbit (opens new window)

    Spotbit's purpose is to allow users to access price feeds in a customisable way that preserves privacy and mitigate the reliance on a single source of data.

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 2:07:17 PM

    + (opens new window)

    # Examples

    Click the links below and learn from community-built example projects.

    # BDK-CLI (opens new window)

    A command line interface to experiment with the bitcoindevkit.

    # DevkitWallet (opens new window)

    A demo app for the bitcoindevkit on Android using bdk-kotlin.

    # Padawan Wallet (opens new window)

    A testnet-only bitcoin wallet full of tutorials on how to use bitcoin wallets.

    # BDKSwiftExampleWallet (opens new window)

    An example iOS app using bdk-swift.

    # Tatooine (opens new window)

    Tatooine is a small bitcoin testnet faucet built with Ktor, a Kotlin asynchronous framework for creating microservices and web applications.

    # SEBA Bank Proof of reserves (opens new window)

    The bdk library aims to be the core building block for Bitcoin wallets of any kind. The bdk-reserves library provides an implementation of proof-of-reserves for bdk.

    # Stackmate (opens new window)

    A multi-purpose Bitcoin Wallet.

    # Spotbit (opens new window)

    Spotbit's purpose is to allow users to access price feeds in a customisable way that preserves privacy and mitigate the reliance on a single source of data.

    Edit this page (opens new window)
    Last Updated: 11/14/2023, 6:02:03 PM

    ←

    Copyright © 2023 BDK Developers

    - + diff --git a/foundation/index.html b/foundation/index.html index 3568b5794a..49e7afe508 100644 --- a/foundation/index.html +++ b/foundation/index.html @@ -29,7 +29,7 @@ - + @@ -84,6 +84,6 @@

    Copyright © 2023 BDK Developers

    - + diff --git a/getting-started/index.html b/getting-started/index.html index 9f9b8e8297..60f33c04d2 100644 --- a/getting-started/index.html +++ b/getting-started/index.html @@ -31,7 +31,7 @@ - + @@ -117,7 +117,7 @@ wallet.get_descriptor_for_keychain(KeychainKind::External).to_string(), wallet.get_descriptor_for_keychain(KeychainKind::Internal).to_string()); } -

    More information about each component used in the code can be found in BDK Documentation (opens new window).

    +

    More information about each component used in the code can be found in BDK Documentation (opens new window).

    Introduction → @@ -140,6 +140,6 @@

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/index.html b/index.html index 9f0e440d5c..0d6406341e 100644 --- a/index.html +++ b/index.html @@ -29,7 +29,7 @@ - + @@ -90,6 +90,6 @@
    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/supporters/index.html b/supporters/index.html index deeec2206a..be1d31329b 100644 --- a/supporters/index.html +++ b/supporters/index.html @@ -29,7 +29,7 @@ - + @@ -75,7 +75,7 @@ Brink Sponsor Kraken Kraken -
    - + diff --git a/tutorials/bdk-cli_basics_multisig_2of3/index.html b/tutorials/bdk-cli_basics_multisig_2of3/index.html index 09e1ccf5ed..d13bef1f18 100644 --- a/tutorials/bdk-cli_basics_multisig_2of3/index.html +++ b/tutorials/bdk-cli_basics_multisig_2of3/index.html @@ -30,7 +30,7 @@ - + @@ -127,7 +127,7 @@

    # Step 12: Broadcast Transaction

    ▶️ bdk-cli wallet --wallet wallet_name_msd01 --descriptor $MULTI_DESCRIPTOR_01 broadcast --psbt $SECONDSIG_PSBT

    {
   "txid": "61da2451874a483aa8d1d0787c7680d157639f284840de8885098cac43f6cc2f"
 }
-

    # Verify Transaction

    Verify transcation in the memory pool on testnet Mempool-testnet! (opens new window)

    +

    # Verify Transaction

    Verify transcation in the memory pool on testnet Mempool-testnet! (opens new window)

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/bdk_cli_basics/index.html b/tutorials/bdk_cli_basics/index.html index c46cd95dd3..b539100a3c 100644 --- a/tutorials/bdk_cli_basics/index.html +++ b/tutorials/bdk_cli_basics/index.html @@ -30,7 +30,7 @@ - + @@ -162,7 +162,7 @@ bdk-cli wallet --descriptor $env:my_descriptor broadcast --psbt $env:PSBTSIGNED

    👍 The output below confirms the command was successful.

    {
   "txid": "a0877b7ce91ea6d141ba63277673f5bdf0edfdd45f91a39ba1a1ace15f839b52"
 }
-

    TIP

    Run sync one more time and see that the balance has decreased.

    # Resources

    +

    TIP

    Run sync one more time and see that the balance has decreased.

    # Resources

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/bdk_with_tor/index.html b/tutorials/bdk_with_tor/index.html index acb862a164..1f7ece9385 100644 --- a/tutorials/bdk_with_tor/index.html +++ b/tutorials/bdk_with_tor/index.html @@ -30,7 +30,7 @@ - + @@ -307,7 +307,7 @@ }

    In this example we start Tor first, then use the address returned by start_tor() function as proxy address.

    We omitted find_string_in_log() and truncate_log() for brevity. You -can find their implementations in esplora_backend_with_tor.rs (opens new window)

    +can find their implementations in esplora_backend_with_tor.rs (opens new window)

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/compact_filters_demo/index.html b/tutorials/compact_filters_demo/index.html index 3aa4d174eb..870e8ebdaa 100644 --- a/tutorials/compact_filters_demo/index.html +++ b/tutorials/compact_filters_demo/index.html @@ -30,7 +30,7 @@ - + @@ -187,7 +187,7 @@ "satoshi": 299999859 }

    If you see the balance updated, voila!

    What happened here is:

    # Shutdown Docker

    You may now shutdown the regtest docker container.

    Note: This will also clean up any data in the bitcoin core, including the wallet.

    $ docker kill bdk-box
-

    # End Words

    In this tutorial we went through the process of receiving, creating, signing and broadcasting transaction using the BDK wallet with compact_filters feature. This demonstrates how BDK capabilities can be used to create SPV light wallets with integrated BIP157 type compact_filters node.

    +

    # End Words

    In this tutorial we went through the process of receiving, creating, signing and broadcasting transaction using the BDK wallet with compact_filters feature. This demonstrates how BDK capabilities can be used to create SPV light wallets with integrated BIP157 type compact_filters node.

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/descriptor_based_paper_wallet/index.html b/tutorials/descriptor_based_paper_wallet/index.html index 667e4e62f7..ddd0486127 100644 --- a/tutorials/descriptor_based_paper_wallet/index.html +++ b/tutorials/descriptor_based_paper_wallet/index.html @@ -30,7 +30,7 @@ - + @@ -142,7 +142,7 @@ Rusty Paper Wallet (opens new window) and then sweep the funds from our example paper wallet to a new address. If you found this post interesting please comment below. Or give it a try yourself and if you run into any problems or would like to suggest improvements leave an issue in the Rusty Paper Wallet (opens new window) or -bdk-cli (opens new window) github repos. Thanks!

    1. Wallet Input Format, a string encoding a ECDSA private key https://en.bitcoin.it/wiki/Wallet_import_format ↩︎

    2. Unless the user import the WIF directly into bitcoin core ↩︎

    3. Some wallets refers to sweep as the action to create a transaction taking all the funds from the paper wallet and sending those to the wallet itself. ↩︎

    4. Ideally, the black zone should be twice as long as the secret part to cover it back and front, long descriptor may leave a shorter black zone, ensure to have you printer set with vertical layout for best results. ↩︎

    +bdk-cli (opens new window) github repos. Thanks!

    1. Wallet Input Format, a string encoding a ECDSA private key https://en.bitcoin.it/wiki/Wallet_import_format ↩︎

    2. Unless the user import the WIF directly into bitcoin core ↩︎

    3. Some wallets refers to sweep as the action to create a transaction taking all the funds from the paper wallet and sending those to the wallet itself. ↩︎

    4. Ideally, the black zone should be twice as long as the secret part to cover it back and front, long descriptor may leave a shorter black zone, ensure to have you printer set with vertical layout for best results. ↩︎

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/descriptors_in_the_wild/index.html b/tutorials/descriptors_in_the_wild/index.html index 5bf4234c1e..a1391da30b 100644 --- a/tutorials/descriptors_in_the_wild/index.html +++ b/tutorials/descriptors_in_the_wild/index.html @@ -30,7 +30,7 @@ - + @@ -198,7 +198,7 @@

    # Conclusion

    We have built an HDM and we have used it with two indipendent wallets, which are compatible with BIP 174 (opens new window) and Output Descriptors (opens new window). Hopefully we will see many other compatible wallets beyound Bitcoin Core (opens new window) and BDK (opens new window), -with which we will be able to easily set up multi signature schemes.

    +with which we will be able to easily set up multi signature schemes.

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/exploring_bdk_flutter/index.html b/tutorials/exploring_bdk_flutter/index.html index 2257266e0d..8966e5aa8a 100644 --- a/tutorials/exploring_bdk_flutter/index.html +++ b/tutorials/exploring_bdk_flutter/index.html @@ -30,7 +30,7 @@ - + @@ -455,7 +455,7 @@ ) ) -

    We should now be able to send a transaction as long as there is sufficient balance.

    # Conclusion

    The App we created can be built and distributed for both iOS and Android thus sharing a code base and reducing development time. The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by bdk-flutter allowing us to focus on the product, functionality, and user journey. This is how bdk and bdk-flutter intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while bdk handles bitcoin complexity.

    bdk-flutter intends to expose functionality and APIs from bdk which has a wide variety of APIs with granular details allowing for many interesting use cases to be implemented. bdk-flutter and bdk are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.

    Stay tuned for more APIs and enhancements coming to bdk-flutter in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of bdk-flutter.

    In the meantime keep in touch with the project by following us on GitHub (opens new window) and Twitter (opens new window)

    # References:

    +

    We should now be able to send a transaction as long as there is sufficient balance.

    # Conclusion

    The App we created can be built and distributed for both iOS and Android thus sharing a code base and reducing development time. The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by bdk-flutter allowing us to focus on the product, functionality, and user journey. This is how bdk and bdk-flutter intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while bdk handles bitcoin complexity.

    bdk-flutter intends to expose functionality and APIs from bdk which has a wide variety of APIs with granular details allowing for many interesting use cases to be implemented. bdk-flutter and bdk are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.

    Stay tuned for more APIs and enhancements coming to bdk-flutter in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of bdk-flutter.

    In the meantime keep in touch with the project by following us on GitHub (opens new window) and Twitter (opens new window)

    # References:

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/exploring_bdk_rn/index.html b/tutorials/exploring_bdk_rn/index.html index c9594aabb3..5bacf32645 100644 --- a/tutorials/exploring_bdk_rn/index.html +++ b/tutorials/exploring_bdk_rn/index.html @@ -30,7 +30,7 @@ - + @@ -365,7 +365,7 @@ /> </Fragment> </View> -

    We should now be able to send a transaction as long as there is sufficient balance.

    # Conclusion

    The App we created can be built and distributed for both iOS and Android thus sharing a code base and reducing development time. The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by bdk-rn allowing us to focus on the product, functionality and user journey. This is how bdk and bdk-rn intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while bdk handles bitcoin complexity.

    bdk-rn intends to expose functionality and APIs from bdk which has a wide variety of API with granular details allowing for many interesting use cases to be implemented. bdk-rn and bdk are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.

    Stay tuned for more APIs and enhancements coming to bdk-rn in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of bdk-rn.

    In the meantime keep in touch with the project by following on GitHub (opens new window) and Twitter (opens new window)

    # References:

    +

    We should now be able to send a transaction as long as there is sufficient balance.

    # Conclusion

    The App we created can be built and distributed for both iOS and Android thus sharing a code base and reducing development time. The development and coding focused on application-level code for use cases and we did not have to code intricate internal bitcoin protocol-level code or bitcoin node interactions, and transactions. UTXOs and sync-related functionalities were also not required. All this was managed by bdk-rn allowing us to focus on the product, functionality and user journey. This is how bdk and bdk-rn intend to make Rapid Bitcoin Application Development possible by allowing product and application developers to focus on what they know best while bdk handles bitcoin complexity.

    bdk-rn intends to expose functionality and APIs from bdk which has a wide variety of API with granular details allowing for many interesting use cases to be implemented. bdk-rn and bdk are constantly updated and enhanced based on feedback from product teams and developers in the bitcoin community.

    Stay tuned for more APIs and enhancements coming to bdk-rn in the near future. Feature and API requests are most welcome. New blogs and tutorials will be published soon for a more in-depth exploration of bdk-rn.

    In the meantime keep in touch with the project by following on GitHub (opens new window) and Twitter (opens new window)

    # References:

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/hidden-power-of-bitcoin/index.html b/tutorials/hidden-power-of-bitcoin/index.html index 3bc06b1acf..31eb0835e7 100644 --- a/tutorials/hidden-power-of-bitcoin/index.html +++ b/tutorials/hidden-power-of-bitcoin/index.html @@ -30,7 +30,7 @@ - + @@ -401,7 +401,7 @@ Hence, we saw that we can generate some smart contracts using Bitcoin.

    # Inspirations

    1. Descriptors from Bitcoin Core (opens new window)
    2. Miniscript (opens new window)
    3. Output Script Descriptors (opens new window)
    4. Descriptors in Bitcoin Dev Kit (opens new window)
    5. Role of Descriptors (opens new window)
    6. Making a Taproot Descriptor Wallet using bitcoin-cli (opens new window)
    7. Miniscripts SBC '19 - Video (opens new window)
    8. Rethinking Wallet Architecture: Native Descriptor Wallets - Video (opens new window)

    Special thanks to my mentor Steve Myers (opens new window) for the constant motivation and support he gave me and for clearing so many doubts! Immense thanks to Raj (opens new window) for reviewing this blog and giving such detailed suggestions. Many of the lines added here are his. -Also, thanks to the folks at the #miniscript IRC channel to help me out with the Retention Bonus policy.

    This blog was written during Summer of Bitcoin 2021 (opens new window) by Sandipan Dey (opens new window).

    +Also, thanks to the folks at the #miniscript IRC channel to help me out with the Retention Bonus policy.

    This blog was written during Summer of Bitcoin 2021 (opens new window) by Sandipan Dey (opens new window).

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/spending_policy_demo/index.html b/tutorials/spending_policy_demo/index.html index 2324ee1f6d..dad35620d8 100644 --- a/tutorials/spending_policy_demo/index.html +++ b/tutorials/spending_policy_demo/index.html @@ -30,7 +30,7 @@ - + @@ -318,7 +318,7 @@ { "satoshi": 0 } -

    # Done again!

    In this demo we showed how to receive and spend bitcoin using two different descriptor wallet policies using the bdk library and bdk-cli wallet tool.

    +

    # Done again!

    In this demo we showed how to receive and spend bitcoin using two different descriptor wallet policies using the bdk library and bdk-cli wallet tool.

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - + diff --git a/tutorials/using_bdk_with_hardware_wallets/index.html b/tutorials/using_bdk_with_hardware_wallets/index.html index 760cbb20c7..1d9b147cd3 100644 --- a/tutorials/using_bdk_with_hardware_wallets/index.html +++ b/tutorials/using_bdk_with_hardware_wallets/index.html @@ -30,7 +30,7 @@ - + @@ -182,7 +182,7 @@ blockchain.broadcast(&raw_transaction)?; println!("Transaction broadcasted! TXID: {txid}.\nExplorer URL: https://mempool.space/testnet/tx/{txid}", txid = txid); -

    # Conclusion

    We just received coins on a hardware wallet and spent from it - how cool is that?!

    See the hardware signer example (opens new window) for the full code, and, if you have any questions or suggestions, head to our Discord (opens new window). See you there!

    +

    # Conclusion

    We just received coins on a hardware wallet and spent from it - how cool is that?!

    See the hardware signer example (opens new window) for the full code, and, if you have any questions or suggestions, head to our Discord (opens new window). See you there!

    ←

    BDK Foundation

    Copyright © 2023 BDK Developers

    - +