go-eth-multicall

Minimal golang ethereum multicall implementation

The implementation only supports mainnet but can it is just a matter of pointing to another RPC and address to support other networks.

The module exports a EthMultiCaller struct that is bound to a client and is used to make the queries.

type EthMultiCaller struct {
    Signer          *bind.TransactOpts
    Client          *ethclient.Client
    Abi             abi.ABI
    ContractAddress common.Address
}

Requests/reads are to be defined using the Call struct, and its response will be a CallResponse

type Call struct {
    Name     string         `json:"name"`
    Target   common.Address `json:"target"`
    CallData []byte         `json:"call_data"`
}

type CallResponse struct {
    Success    bool         `json:"success"`
    ReturnData []byte       `json:"returnData"`
}

With a slice of Calls, one can perform Execute(calls) which will return map using the Call.Name as key and CallResponse as value.

Note that you must yourself handle the bytes that is in the ReturnData, e.g., load big.Int and similar.

Example

var erc20Abi, _ = abi.JSON(strings.NewReader(IERC20.IERC20ABI))

func GetBalanceCall(name string, tokenAddress common.Address, userAddress common.Address) Call {
    parsedData, err := erc20Abi.Pack("balanceOf", userAddress)
    if err != nil {
        panic(err)
    }
    return Call{
        Target:   tokenAddress,
        CallData: parsedData,
        Name:     name,
    }
}

func main() {
    caller := New(https://mainnet.infura.io/v3/<infurakey>)
    
    userAddress := common.HexToAddress("0xb1adceddb2941033a090dd166a462fe1c2029484")
    
    
    var userCalls = make([]Call, 0)
    userCalls = append(userCalls, GetBalanceCall("DillBalance", common.HexToAddress("0xbBCf169eE191A1Ba7371F30A1C344bFC498b29Cf"), userAddress))
    userCalls = append(userCalls, GetBalanceCall("PickleBalance", common.HexToAddress("0x429881672B9AE42b8EbA0E26cD9C73711b891Ca5"), userAddress))
    
    response := caller.Execute(userCalls)
    
    for key, value := range response {
        val := new(big.Int).SetBytes(value.ReturnData)
        println(key, val.String())
    }
}