Ether Roulette

Project structure

This is a standard truffle package layout:

• /contracts/ - solidity contracts source code
• /migrations/ - truffle migrations that deploy contracts to the blockchain
• /build/ - compiled contracts
• /test/ - contracts tests
• /webapp/ - standalone web application

Setting up the project

Install all the dependencies

https://metamask.io/

$ npm install

Runs npm install for /webapp and /testrpc in postinstall script.

Running the project

Start TestRPC

$ npm run testrpc

TestRPC acts like a local chain for testing and developement. It does not persist any state between runs.

In addition to running TestRPC, this command also compiles and deploys contracts to TestRPC. It removes previously built ABIs from build/contracts to smooth local development, but this behaviour is not suitable for deployment to any public network.

Running tests

$ npm run test

Compiling contracts manually

$ npm run compile

This generates contracts ABIs (compiled interfaces) in /build/ directory.

Deploying contracts to the chain

$ npm run migrate

This published contracts to the blockchain and copies their generated addresses to their interfaces stored in /build/.

Note that if you're running npm run testrpc contracts are compiled and migrated automatically, without a need for compile and migrate. Normally, each time testrpc is started contracts would have to be migrated.

Starting the webapp

cd webapp
npm run start

Note that web application requires contracts to be compiled and deployed first. It directly imports their interfaces from json files in ./build/.

Using webapp with MetaMask and TestRPC

When running for the first time:

1. Open metamask (Click on the fox icon in menubar)
2. Connect to localhost (Click on the network in the upper left corner and choose "localhost 8545")
3. Import TestRPC account (Click "Import existing DEN")
   1. Provide a seed: "spike dizzy clump wrist receive limb interest half item lunch betray vivid" (it comes from TestRPC output and is hardcoded package.json)

Troubleshooting

• Each time TestRPC is restarted, browser has to be restarted as well.
• After each migration webapp should be reloaded
• If you're getting VM Errors in migrations rm -r /build/. Happens especially after switching branches.

References

• https://github.com/pragmaticcoders/ether-lotto

• https://solidity.readthedocs.io/en/develop/solidity-in-depth.html

• http://truffleframework.com/docs/

• https://metamask.io/