use alchemy rpc url (#43)

Co-authored-by: John Guilding <[email protected]>

packages/backend/.env.example

@@ -6,13 +6,13 @@ APP_PASSWORD=""
 HAT_ID=""
 # The private key of the EVM account
 ETH_PRIVATE_KEY=""
-# The RPC URL for the EVM network
-RPC_URL=""
 # The path to the TLS cert
 TLS_CERT=""
 # The path to the TLS key
 TLS_KEY=""
 # The port to listen on
 PORT=""
 # The IP to bind to
-BIND_IP=""
+BIND_IP=""
+# Alchemy ID
+ALCHEMY_ID=""

packages/backend/src/account.ts

@@ -2,6 +2,7 @@ import { createPublicClient, createWalletClient, http} from 'viem'
 import { privateKeyToAccount } from 'viem/accounts'
 import { PRIVATE_KEY } from './constants'
 import getNetwork from './getNetwork';
+import { getRpcUrl } from './getRpcUrl';
 
 // create an account from the private key
 export const account = privateKeyToAccount(PRIVATE_KEY)
@@ -11,12 +12,12 @@ const chain = getNetwork();
 // a public client for reading data
 export const publicClient = createPublicClient({
     chain,
-    transport: http()
+    transport: http(getRpcUrl())
 })
 
 // a wallet client for signing transactions
 export const walletClient = createWalletClient({
     account,
     chain,
-    transport: http()
+    transport: http(getRpcUrl())
 })

packages/backend/src/getRpcUrl.ts

@@ -0,0 +1,22 @@
+import getNetwork from "./getNetwork";
+
+/**
+ * Get the RPC URL based on the network we are connected to
+ * @returns the alchemy RPC URL
+ */
+export const getRpcUrl = (): string => {
+    const chainId = getNetwork().id;
+
+    if (!process.env.ALCHEMY_ID) {
+        throw new Error("ALCHEMY_ID is not set");
+    }
+
+    switch (chainId) {
+      case 10:
+        return `https://opt-mainnet.g.alchemy.com/v2/${process.env.ALCHEMY_ID}`;
+      case 11155420:
+        return `https://opt-sepolia.g.alchemy.com/v2/${process.env.ALCHEMY_ID}`;
+      default:
+        return `https://opt-sepolia.g.alchemy.com/v2/${process.env.ALCHEMY_ID}`;
+    }
+  };

packages/interface/src/utils/hatsProtocol.ts

@@ -1,7 +1,7 @@
 import { HatsClient } from "@hatsprotocol/sdk-v1-core";
 import { createPublicClient, http, type PublicClient } from "viem";
 
-import { config } from "~/config";
+import { config, getRPCURL } from "~/config";
 
 /**
  * Get an HatsClient instance to check whether the connected wallet owns the required hat
@@ -10,7 +10,7 @@ import { config } from "~/config";
 export const getHatsClient = (): HatsClient => {
   const client = createPublicClient({
     chain: config.network,
-    transport: http(),
+    transport: http(getRPCURL()),
   });
 
   const hatsClient = new HatsClient({