feat: add getBalance endpoint using etherscan api (#58)

* feat: add balance api endpoint

* feat: etherscan api key

front/.env.local.example

@@ -1,4 +1,5 @@
 NEXT_PUBLIC_STACKUP_BUNDLER_API_KEY=""
-NEXT_PUBLIC_RPC_ENDPOINT="https://eth-sepolia.g.alchemy.com/v2/N5ZVikrQ0kBZLVjyY8GwbpYSLPLRuINB"
+NEXT_PUBLIC_RPC_ENDPOINT=""
+ETHERSCAN_API_KEY=""
 NEXT_PUBLIC_FACTORY_CONTRACT_ADDRESS="0xDD0f9cB4Cf53d28b976C13e7ee4a169F841924c0"
 RELAYER_PRIVATE_KEY=""

front/src/app/api/balance/[address]/route.ts

@@ -0,0 +1,15 @@
+import { Hex, stringify } from "viem";
+
+export async function GET(_req: Request, { params }: { params: { address: Hex } }) {
+  const { address } = params;
+  if (!address) {
+    return Response.json(JSON.parse(stringify({ error: "address is required" })));
+  }
+  const result = await fetch(
+    `https://api-sepolia.etherscan.io/api?module=account&action=balance&address=${address}&tag=latest&apikey=${process.env.ETHERSCAN_API_KEY}`,
+  );
+  const resultJSON = await result.json();
+  const balance = BigInt(resultJSON?.result || 0);
+
+  return Response.json(JSON.parse(stringify({ balance })));
+}

front/src/app/api/users/[id]/route.ts

@@ -15,6 +15,17 @@ export async function GET(_req: Request, { params }: { params: { id: Hex } }) {
     args: [BigInt(id)],
   });
 
-  const balance = await PUBLIC_CLIENT.getBalance({ address: user.account });
+  //const balance = await PUBLIC_CLIENT.getBalance({ address: user.account });
+  let balance = BigInt(0);
+
+  // Using etherscan api instead of getBalance as Sepolia rcp node is not inconsistent
+  if (user?.account) {
+    const result = await fetch(
+      `https://api-sepolia.etherscan.io/api?module=account&action=balance&address=${user.account}&tag=latest&apikey=${process.env.ETHERSCAN_API_KEY}`,
+    );
+    const resultJSON = await result.json();
+    balance = BigInt(resultJSON?.result || 0);
+  }
+
   return Response.json(JSON.parse(stringify({ ...user, id: toHex(user.id), balance })));
 }

front/src/libs/factory/getBalance.ts

@@ -0,0 +1,14 @@
+import { Address, Hex } from "viem";
+
+export type User = { id: Hex; pubKey: { x: Hex; y: Hex }; account: Address; balance: bigint };
+
+export async function getBalance(address: Hex): Promise<{ balance: bigint }> {
+  const response = await fetch(`/api/balance/${address}`, {
+    method: "GET",
+  });
+
+  const user = await response.json();
+  return {
+    balance: user.balance,
+  };
+}

front/src/providers/BalanceProvider/index.tsx

@@ -1,9 +1,9 @@
 "use client";
 
-import { getUser } from "@/libs/factory/getUser";
+import { getBalance } from "@/libs/factory/getBalance";
 import { useMe } from "@/providers/MeProvider";
 import { createContext, useCallback, useContext, useEffect, useRef, useState } from "react";
-import { Hex, formatEther, zeroAddress } from "viem";
+import { Hex, formatEther } from "viem";
 
 function useBalanceHook() {
   // balance in usd
@@ -12,15 +12,11 @@ function useBalanceHook() {
 
   const { me } = useMe();
 
-  const getBalance = useCallback(async (keyId: Hex) => {
-    const user = await getUser(keyId);
-    if (user?.account === zeroAddress || user?.account === undefined) {
-      setBalance("0.00");
-      return;
-    }
+  const getBalanceUSD = useCallback(async (address: Hex) => {
+    const res = await getBalance(address);
     const priceData = await fetch("/api/price?ids=ethereum&currencies=usd");
     const price: number = Math.trunc((await priceData.json()).ethereum.usd * 100);
-    const balance = formatEther((BigInt(user.balance) * BigInt(price)) / BigInt(100));
+    const balance = formatEther((BigInt(res.balance) * BigInt(price)) / BigInt(100));
     setBalance(balance);
   }, []);
 
@@ -31,17 +27,17 @@ function useBalanceHook() {
   let interval = useRef<NodeJS.Timeout | null>(null);
 
   useEffect(() => {
-    if (!me?.keyId) return;
-    getBalance(me?.keyId);
+    if (!me?.account) return;
+    getBalanceUSD(me?.account);
     interval.current && clearInterval(interval.current);
     interval.current = setInterval(() => {
-      getBalance(me?.keyId);
-    }, 3000);
+      getBalanceUSD(me?.account);
+    }, 5000);
 
     return () => {
       interval.current && clearInterval(interval.current);
     };
-  }, [me, getBalance, increment]);
+  }, [me?.account, getBalanceUSD, increment]);
 
   return {
     balance,