RPC Overrides

.env.example

@@ -1 +1,2 @@
-NEXT_PUBLIC_WALLET_CONNECT_ID=12345678901234567890123456789012
+NEXT_PUBLIC_WALLET_CONNECT_ID=12345678901234567890123456789012
+NEXT_PUBLIC_RPC_OVERRIDES='{"chain1":{"http":"https://..."}}'

.eslintrc

@@ -15,12 +15,12 @@
   "extends": [
     "eslint:recommended",
     "plugin:@typescript-eslint/recommended",
-    "next", 
-    "next/core-web-vitals", 
+    "next",
+    "next/core-web-vitals",
     "prettier"
   ],
   "rules": {
-    "no-console": ["warn"],
+    "no-console": ["error"],
     "no-eval": ["error"],
     "no-ex-assign": ["error"],
     "no-constant-condition": ["off"],

src/consts/config.ts

@@ -7,6 +7,7 @@ const explorerApiKeys = JSON.parse(process?.env?.EXPLORER_API_KEYS || '{}');
 const walletConnectProjectId = process?.env?.NEXT_PUBLIC_WALLET_CONNECT_ID || '';
 const withdrawalWhitelist = process?.env?.NEXT_PUBLIC_BLOCK_WITHDRAWAL_WHITELIST || '';
 const transferBlacklist = process?.env?.NEXT_PUBLIC_TRANSFER_BLACKLIST || '';
+const rpcOverrides = process?.env?.NEXT_PUBLIC_RPC_OVERRIDES || '';
 
 interface Config {
   isDevMode: boolean; // Enables some debug features in the app
@@ -20,6 +21,7 @@ interface Config {
   transferBlacklist: string; // comma-separated list of routes between which transfers are disabled. Expects Caip2Id-Caip2Id (e.g. ethereum:1-sealevel:1399811149)
   enableExplorerLink: boolean; // Include a link to the hyperlane explorer in the transfer modal
   addressBlacklist: string[]; // A list of addresses that are blacklisted and cannot be used in the app
+  rpcOverrides: string;
 }
 
 export const config: Config = Object.freeze({
@@ -34,4 +36,5 @@ export const config: Config = Object.freeze({
   transferBlacklist,
   enableExplorerLink: false,
   addressBlacklist: ADDRESS_BLACKLIST.map((address) => address.toLowerCase()),
+  rpcOverrides,
 });

src/context/chains.ts

@@ -1,12 +1,13 @@
 import { z } from 'zod';
 
 import { GithubRegistry, chainMetadata } from '@hyperlane-xyz/registry';
-import { ChainMap, ChainMetadata, ChainMetadataSchema } from '@hyperlane-xyz/sdk';
+import { ChainMap, ChainMetadata, ChainMetadataSchema, RpcUrlSchema } from '@hyperlane-xyz/sdk';
 
 import { chains as ChainsTS } from '../consts/chains.ts';
 import ChainsYaml from '../consts/chains.yaml';
 import { config } from '../consts/config.ts';
 import { cosmosDefaultChain } from '../features/chains/cosmosDefault';
+import { tryParseJson } from '../utils/json.ts';
 import { logger } from '../utils/logger';
 
 export async function assembleChainMetadata() {
@@ -20,6 +21,12 @@ export async function assembleChainMetadata() {
     logger.warn('Invalid chain config', result.error);
     throw new Error(`Invalid chain config: ${result.error.toString()}`);
   }
+
+  const rpcOverrides = z.record(RpcUrlSchema).safeParse(tryParseJson(config.rpcOverrides));
+  if (config.rpcOverrides && !rpcOverrides.success) {
+    logger.warn('Invalid RPC overrides config', rpcOverrides.error);
+  }
+
   const customChainMetadata = result.data as ChainMap<ChainMetadata>;
 
   const registry = new GithubRegistry({ uri: config.registryUrl });
@@ -34,6 +41,22 @@ export async function assembleChainMetadata() {
     await registry.listRegistryContent();
   }
 
-  const chains = { ...defaultChainMetadata, ...customChainMetadata };
+  const chains: ChainMap<ChainMetadata> = Object.entries({
+    ...defaultChainMetadata,
+    ...customChainMetadata,
+  }).reduce(
+    (accum, [name, chain]) => ({
+      ...accum,
+      [name]:
+        rpcOverrides.success && rpcOverrides.data[name]
+          ? {
+              ...chain,
+              rpcUrls: [rpcOverrides.data[name]],
+            }
+          : chain,
+    }),
+    {} as ChainMap<ChainMetadata>,
+  );
+
   return { chains, registry };
 }

src/utils/json.ts

@@ -0,0 +1,10 @@
+import { logger } from './logger';
+
+export function tryParseJson(input: string): unknown | null {
+  try {
+    return JSON.parse(input);
+  } catch (e) {
+    logger.warn('unable to parse JSON', e);
+    return null;
+  }
+}