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.
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())
}
}