[Go] Web3 Use Smart Contract Query Wallet Multi Balance

使用 github.com/ethereum/go-ethereum , 查詢鏈上錢包多幣種餘額

1. 智能合約是 MutiCall
   Multicall | Address 0xeefba1e63905ef1d7acba5a8513c70307c1ce441 | Etherscan
2. 這邊也會使用到 ERC20 的 ABI
   Google 一下複製下來就行

func main() {
 client, err := ethclient.Dial("https://mainnet.infura.io/v3/21e4ec6a577c4062a7a097278a55d9eb")
 if err != nil {
  log.Fatalf("Failed to connect to the Ethereum client: %v", err)
 }

 erc20Abi, err := abi.JSON(strings.NewReader(ERC20ABI))
 if err != nil {
  panic(err)
 }

 b, _ := os.ReadFile("./multi_call.abi")
 multiABI, err := abi.JSON(bytes.NewReader(b))
 if err != nil {
  panic(err)
 }

 // 查詢 0x00192Fb10dF37c9FB26829eb2CC623cd1BF599E8 的餘額
 balanceOf, _ := erc20Abi.Pack("balanceOf", common.HexToAddress("0x00192Fb10dF37c9FB26829eb2CC623cd1BF599E8"))
 // 使用 智能合約裡面的 aggregate 方法
 b, err = multiABI.Pack("aggregate", []Struct0{
  {
   // 什麼樣的幣種
   Target:   common.HexToAddress("0x86b78c93Eea132BFD942E1f316bAB02A127dfC84"),
   CallData: balanceOf,
  },
  {
   // 什麼樣的幣種
   Target:   common.HexToAddress("0x1dd34B35d96f5159567EF4caD2c69C0f87c3195c"),
   CallData: balanceOf,
  },
 })
 if err != nil {
  panic(err)
 }

 multiCallContract := common.HexToAddress("0xeefba1e63905ef1d7acba5a8513c70307c1ce441")
 b, err = client.CallContract(context.Background(), ethereum.CallMsg{
  To:   &multiCallContract,
  Data: b,
 }, nil)
 if err != nil {
  fmt.Printf("%+v %+v\n", b, err)
  return
 }

 var out AggregateResponse

 err = multiABI.UnpackIntoInterface(&out, "aggregate", b)
 if err != nil {
  fmt.Printf("%+v %+v\n", b, err)
 }

 for _, i := range out.ReturnData {
  out, _ := erc20Abi.Unpack("balanceOf", i[:])
  fmt.Printf("%+v\n", out)
 }
}

這邊主要用到 “github.com/ethereum/go-ethereum/accounts/abi”
會用到 Pack, Unpack, 大概就是 json marshal, unMarshal 的意思

跟智能合約的交互 http 沒什麼差別, 都是 Request Response, 主要是 Build Request Response 會有點麻煩