BalanceChecker & Agex Project Integration

What is BalanceChecker?

BalanceChecker is a Solidity smart contract designed to efficiently retrieve the ETH and ERC20 token balances for one or more addresses with a single on-chain call. It offers two primary functions:

• getAllTokensBalances: Accepts arrays of user addresses and token addresses (with address(0) representing ETH) and returns an array of BalanceInfo structs. Each struct includes:

  • user: The address queried.
  • token: The token address (or zero for ETH).
  • balance: The balance of the token or ETH.
  • blockNumber & blockTimestamp: The block details at the time of the query.

• getSelectedTokenBalances: Accepts an array of BalanceRequest structs for specific user-token pairs and returns their corresponding balance information.

The contract ensures robustness by:

• Checking if a token address is a contract (using extcodesize in assembly) before attempting to call balanceOf.
• Reverting any ETH transfers via its fallback and receive functions, which helps prevent accidental transfers.

How to Use BalanceChecker

1. Deployment:
   Deploy the BalanceChecker contract on your preferred Ethereum-compatible network.

2. Querying Balances:

   • Batch Querying:
     Use getAllTokensBalances to fetch both ETH and token balances for multiple addresses:

     address[] memory users = new address[](2);
     users[0] = 0x123...;
     users[1] = 0x456...;
     
     address[] memory tokens = new address[](2);
     tokens[0] = tokenAddress; // ERC20 token address
     tokens[1] = address(0);   // ETH balance
     
     BalanceChecker.BalanceInfo[] memory results = balanceChecker.getAllTokensBalances(users, tokens);

   • Selective Querying:
     Use getSelectedTokenBalances if you need balances for specific user-token pairs:

     BalanceChecker.BalanceRequest[] memory requests = new BalanceChecker.BalanceRequest[](1);
     requests[0] = BalanceChecker.BalanceRequest({user: 0x123..., token: tokenAddress});
     BalanceChecker.BalanceInfo[] memory result = balanceChecker.getSelectedTokenBalances(requests);

How Agex Uses BalanceChecker

In the Agex project, the BalanceChecker contract is integrated into the backend via the BatchBalanceService written in Python. This service leverages Web3.py to interact with the deployed contract and fetch token balances in a single batch call.

BatchBalanceService

• Connection Setup:
  The service initializes a Web3 connection with the provided RPC endpoint and loads the contract using its ABI and deployed address.

• Fetching Balances:
  The get_batch_balance method accepts an address, converts it to checksum format, and calls the contract’s getAllTokensBalances function.

Foundry

Foundry is a blazing fast, portable and modular toolkit for Ethereum application development written in Rust.

Foundry consists of:

• Forge: Ethereum testing framework (like Truffle, Hardhat and DappTools).
• Cast: Swiss army knife for interacting with EVM smart contracts, sending transactions and getting chain data.
• Anvil: Local Ethereum node, akin to Ganache, Hardhat Network.
• Chisel: Fast, utilitarian, and verbose solidity REPL.

Documentation

https://book.getfoundry.sh/

Usage

Build

$ forge build

Test

$ forge test

Format

$ forge fmt

Deploy

$ forge script script/BalanceChecker.s.sol:BalanceCheckerScript --rpc-url <your_rpc_url> --private-key <your_private_key>

Help

$ forge --help
$ anvil --help
$ cast --help

Dependency

forge install OpenZeppelin/openzeppelin-contracts --no-commit