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"
	},
]
`