Evm解析交易中合约数据

以下是在以太坊部署Uniswap调用合约的TxHash。 https://cn.etherscan.com/tx/0x06e68f7061f4d7da8117dc0ed97cd9888305590002d05811baa6594b10eb9cd1/

此交易调用合约方法swapETHForExactTokens,通过解析Input可以拿到合约输入参数。

有如下要点

• 加载合约ABI
• 通过Input获取合约方法
• Unpack解包输入参数

测试用例代码

func TestParseDepositInput(t *testing.T) {
    input := "fb3bdb41000000000000000000000000000000000000000000108b2a2c280290940000000000000000000000000000000000000000000000000000000000000000000080000000000000000000000000b634058bd3ac146b128824e4b9ab59561b0568b9000000000000000000000000000000000000000000000000000000005f3f6a000000000000000000000000000000000000000000000000000000000000000002000000000000000000000000c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2000000000000000000000000ed1199093b1abd07a368dd1c0cdc77d8517ba2a0"
    inputData, _ := hex.DecodeString(input)
    abiStaking, _ := abi.JSON(strings.NewReader(Json))
    methodName, err := abiStaking.MethodById(inputData)
    data := inputData[4:]
    args := struct {
        AmountOut *big.Int
        Path    []common.Address
        To    common.Address
        Deadline  *big.Int
    }{}
    method, _ := abiStaking.Methods[methodName.Name]

    err = method.Inputs.Unpack(&args, data)
    if err != nil {
        log.Error("Unpack deposit pubkey error", "err", err)
    }
    fmt.Println("AmountOut ", hex.EncodeToString(args.AmountOut.Bytes()), " Deadline ", hex.EncodeToString(args.Deadline.Bytes())," ",len(args.Path)," ",args.To.String())
}

以下是Uniswap的factory abi json。

const Json = `
[
    {
        "inputs": [
            {
                "internalType": "address",
                "name": "_factory",
                "type": "address"
            },
            {
                "internalType": "address",
                "name": "_WETH",
                "type": "address"
            }
        ],
        "stateMutability": "nonpayable",
        "type": "constructor"
    },
    {
        "inputs": [],
        "name": "WETH",
        "outputs": [
            {
                "internalType": "address",
                "name": "",
                "type": "address"
            }
        ],
        "stateMutability": "view",
        "type": "function"
    },
    {
        "inputs": [
            {
                "internalType": "address",
                "name": "token",
                "type": "address"
            },
            {
                "internalType": "uint256",
                "name": "amountTokenDesired",
                "type": "uint256"
            },
            {
                "internalType": "uint256",
                "name": "amountTokenMin",
                "type": "uint256"
            },
            {
                "internalType": "uint256",
                "name": "amountETHMin",
                "type": "uint256"
            },
            {
                "internalType": "address",
                "name": "to",
                "type": "address"
            },
            {
                "internalType": "uint256",
                "name": "deadline",
                "type": "uint256"
            }
        ],
        "name": "addLiquidityETH",
        "outputs": [
            {
                "internalType": "uint256",
                "name": "amountToken",
                "type": "uint256"
            },
            {
                "internalType": "uint256",
                "name": "amountETH",
                "type": "uint256"
            },
            {
                "internalType": "uint256",
                "name": "liquidity",
                "type": "uint256"
            }
        ],
        "stateMutability": "payable",
        "type": "function"
    },
    {
        "inputs": [],
        "name": "factory",
        "outputs": [
            {
                "internalType": "address",
                "name": "",
                "type": "address"
            }
        ],
        "stateMutability": "view",
        "type": "function"
    },
]
`