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Introduction

ethclient is extend go-ethereum client for interact with smart contract.

Features:

• query token balance

• calculate uniswap v2/v3 liquid pool address offline

• sort token address

• encode uniswap v3 path

• uniswap v3 liquid pool x96 price format convert

• query smart contract data

• build contract transaction and main currency transaction

• HD wallet

Install

go get -u github.com/ackermanx/ethclient

Usage

Below is an example which shows some common use cases for ethereum/client. Check client_test.go for more usage.

get balance/token balance/token transfer/main currency transfer

package main

import (
	"context"
	"log"
	"math/big"
	"time"

	"github.com/ackermanx/ethclient"
	"github.com/ackermanx/ethclient/abi"
	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/common"
)

var (
	testKey = "33f46d353f191f8067dc7d256e9d9ee7a2a3300649ff7c70fe1cd7e5d5237da5"
)

func main() {
	var binanceMainnet = `https://data-seed-prebsc-1-s1.binance.org:8545`

	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
	c, err := ethclient.DialContext(ctx, binanceMainnet)
	cancel()
	if err != nil {
		panic(err)
	}

	// get latest height
	ctx, cancel = context.WithTimeout(context.Background(), time.Second*5)
	blockNumber, err := c.BlockNumber(ctx)
	cancel()
	if err != nil {
		panic(err)
	}
	log.Println("latest block number: ", blockNumber)

	// get busd balance
	busdContractAddress := common.HexToAddress("0xed24fc36d5ee211ea25a80239fb8c4cfd80f12ee")
	address := "0xe96e6b50db659935878f6f3b0491B7F192cf5F59"
	bnbBalance, err := c.BalanceAt(context.Background(), common.HexToAddress(address), nil)
	if err != nil {
		panic(err)
	}
	log.Println("bnbBalance: ", bnbBalance.String())
	balance, err := c.BalanceOf(address, busdContractAddress.String())
	if err != nil {
		panic(err)
	}
	log.Printf("address busd balance: %s\n", balance.String())

	// build contract transfer
	tx, err := c.BuildContractTx(
		testKey, "transfer",
		abi.ERC20Abi,
		&busdContractAddress, &bind.TransactOpts{From: common.HexToAddress(address)},
		common.HexToAddress("0x38F32C2473a314d447d681D30e1C0f5D07194371"),
		big.NewInt(100000000000000000),
	)
	if err != nil {
		panic(err)
	}
	err = c.SendTransaction(context.Background(), tx)
	if err != nil {
		panic(err)
	}
	log.Println(tx.Hash().String())

	// send bnb
	tx, err = c.BuildTransferTx(testKey, "0x38F32C2473a314d447d681D30e1C0f5D07194371", &bind.TransactOpts{
		From:     common.HexToAddress("0xe96e6b50db659935878f6f3b0491b7f192cf5f59"),
		Value:    big.NewInt(20000000000000000),
		GasLimit: 21000,
	})
	if err != nil {
		panic(err)
	}
	log.Println(tx.Hash().String())
	err = c.SendTransaction(context.Background(), tx)
	if err != nil {
		panic(err)
	}
}

generate pool address offline

package main

import (
	"fmt"
	"math/big"

	"github.com/ackermanx/ethclient/uniswap"
)

func main() {
	weth := "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
	dai := "0x6b175474e89094c44da98b954eedeac495271d0f"
	pair, err := uniswap.CalculatePoolAddressV2(weth, dai)
	if err != nil {
		panic(err)
	}

	fmt.Printf("weth-dai pair address in uniswap v2: %s\n", pair.String())

	fee := big.NewInt(3000)
	poolAddress, err := uniswap.CalculatePoolAddressV3(weth, dai, fee)
	if err != nil {
		panic(err)
	}
	fmt.Printf("weth-dai pool address in uniswap v3: %s\n", poolAddress.String())
}

JetBrains OS licenses

ethereum had been being developed with GoLand under the free JetBrains Open Source license(s) granted by JetBrains s.r.o., hence I would like to express my thanks here.