From de84604394733d6f6fb60bbc7ee56201f0659263 Mon Sep 17 00:00:00 2001
From: Matthew Pereira <matthewdavidpereira@gmail.com>
Date: Wed, 9 Oct 2024 13:47:02 -0700
Subject: [PATCH] add fallbacks for rpc url

---
 packages/nextjs/scaffold.config.ts             |  3 +--
 packages/nextjs/services/web3/wagmiConfig.tsx  |  6 +++---
 packages/nextjs/utils/scaffold-eth/networks.ts | 13 ++++++++++++-
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/packages/nextjs/scaffold.config.ts b/packages/nextjs/scaffold.config.ts
index 8ad610f..c8e9322 100644
--- a/packages/nextjs/scaffold.config.ts
+++ b/packages/nextjs/scaffold.config.ts
@@ -20,11 +20,10 @@ const scaffoldConfig = {
   // it has no effect if you only target the local network (default is 4000)
   pollingInterval: 30000,
 
-  // This is ours Alchemy's default API key.
   // You can get your own at https://dashboard.alchemyapi.io
   // It's recommended to store it in an env variable:
   // .env.local for local testing, and in the Vercel/system env config for live apps.
-  alchemyApiKey: process.env.NEXT_PUBLIC_ALCHEMY_API_KEY || "oKxs-03sij-U_N0iOlrSsZFr29-IqbuF",
+  alchemyApiKey: process.env.NEXT_PUBLIC_ALCHEMY_API_KEY || "",
 
   // This is ours WalletConnect's default project ID.
   // You can get your own at https://cloud.walletconnect.com
diff --git a/packages/nextjs/services/web3/wagmiConfig.tsx b/packages/nextjs/services/web3/wagmiConfig.tsx
index e207843..c77b97e 100644
--- a/packages/nextjs/services/web3/wagmiConfig.tsx
+++ b/packages/nextjs/services/web3/wagmiConfig.tsx
@@ -1,9 +1,9 @@
 import { wagmiConnectors } from "./wagmiConnectors";
-import { Chain, createClient, http } from "viem";
+import { Chain, createClient, fallback, http } from "viem";
 import { hardhat, mainnet } from "viem/chains";
 import { createConfig } from "wagmi";
 import scaffoldConfig from "~~/scaffold.config";
-import { getAlchemyHttpUrl } from "~~/utils/scaffold-eth";
+import { getAlchemyHttpUrl, getRpcFallbackUrl } from "~~/utils/scaffold-eth";
 
 const { targetNetworks } = scaffoldConfig;
 
@@ -19,7 +19,7 @@ export const wagmiConfig = createConfig({
   client({ chain }) {
     return createClient({
       chain,
-      transport: http(getAlchemyHttpUrl(chain.id)),
+      transport: fallback([http(getAlchemyHttpUrl(chain.id)), http(), http(getRpcFallbackUrl(chain.id))]),
       ...(chain.id !== (hardhat as Chain).id
         ? {
             pollingInterval: scaffoldConfig.pollingInterval,
diff --git a/packages/nextjs/utils/scaffold-eth/networks.ts b/packages/nextjs/utils/scaffold-eth/networks.ts
index 6b8276f..8f525d0 100644
--- a/packages/nextjs/utils/scaffold-eth/networks.ts
+++ b/packages/nextjs/utils/scaffold-eth/networks.ts
@@ -34,11 +34,22 @@ export const RPC_CHAIN_NAMES: Record<number, string> = {
 };
 
 export const getAlchemyHttpUrl = (chainId: number) => {
-  return RPC_CHAIN_NAMES[chainId]
+  return scaffoldConfig.alchemyApiKey && RPC_CHAIN_NAMES[chainId]
     ? `https://${RPC_CHAIN_NAMES[chainId]}.g.alchemy.com/v2/${scaffoldConfig.alchemyApiKey}`
     : undefined;
 };
 
+export const RPC_FALLBACKS: Record<number, string> = {
+  [chains.mainnet.id]: "https://eth.llamarpc.com",
+  [chains.arbitrum.id]: "https://arbitrum.llamarpc.com",
+  [chains.gnosis.id]: "https://gnosis.drpc.org",
+  [chains.sepolia.id]: "https://sepolia.gateway.tenderly.co",
+};
+
+export const getRpcFallbackUrl = (chainId: number) => {
+  return RPC_FALLBACKS[chainId];
+};
+
 export const NETWORKS_EXTRA_DATA: Record<string, ChainAttributes> = {
   [chains.hardhat.id]: {
     color: "#b8af0c",