使用Web3.js查询以太币和代币余额以及转账

r囧r小猫 2022-05-19 04:08 926阅读 0赞

# 前言 #

`web3.js`文档  
[http://web3js.readthedocs.io/en/1.0/][http_web3js.readthedocs.io_en_1.0]

前面的文章也提到了，使用`web3.js`可以与以太坊进行互动。这篇文章的主要内容如下：

1.  解决`web3.js`版本问题

2.使用`web3.js`查询以太币及代币余额，以及进行以太币和代币转账

# 1.web3.js版本问题 #

现在使用`npm install web3`安装的`web3.js`，会发现`node_modules`中的`web3`文件夹中，没有`dist`文件夹，而查看`package.json`内容如下：

{
      "name": "111",
      "version": "1.0.0",
      "description": "",
      "main": "index.js",
      "scripts": {
        "test": "echo \"Error: no test specified\" && exit 1"
      },
      "author": "",
      "license": "ISC",
      "dependencies": {
        "web3": "^1.0.0-beta.34"
      }
    }

会发现`web3`的版本为`"^1.0.0-beta.34"`。

官方文档有这么一句话：

![700][]

大意是这篇文档还在补全中，并且1.0版本的包还没放出。如果要查看当前的0.x.x版本的文档，请戳这里[https://github.com/ethereum/wiki/wiki/JavaScript-API][https_github.com_ethereum_wiki_wiki_JavaScript-API]。我估计这是`web3`文件夹没有`dist`文件夹以及`web3.min.js`的原因。

[之前的文章《以太开发交互实战》][Link 1]也有提供了下载缺失包的地址，但是下载下来的`web3.min.js`很可能是`0.20.6`版本的。因为根据当前`1.0`官方文档进行使用，很多方法运行会出现找不到此方法的错误信息。而我们的`package.json`的`web3`的版本又是`"^1.0.0-beta.34"`，所以干脆直接去下载`1.0.0-beta.34`版本的缺失包使用，还可以就着`1.0`版本的文档食用。

## 1.1 下载1.0.0-beta.34版本的web3.min.js ##

首先进入[https://github.com/ethereum/web3.js][https_github.com_ethereum_web3.js]，点击`Branch`，切换到`Tags`选项，点击`v1.0.0-beta.34`，然后`download`代码，将`dist`文件夹拷贝到自己项目的`moudles`的`web3`文件夹下即可。

# 2. 使用web3.js查询以太币及代币余额以及进行以太币和代币转账 #

## 2.1 在私链和主链上查询以太币及代币余额 ##

查询类方法在私链和主链上的方法都是一样的，说明以下几点：

*  主链地址。可以去`infura`申请
 *  `contractAbi`。合约的abi。可以去[https://etherscan.io][https_etherscan.io]获取，如果代币合约提供了`code`，就会有`abi`

// 引入web3
    var Web3 = require('web3');
    if (typeof web3 !== 'undefined') {
        web3 = new Web3(web3.currentProvider);
    } else {
        // web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:7545"));
        web3 = new Web3(new Web3.providers.HttpProvider("https://mainnet.infura.io/yourAddress"));
    }
    
    // 定义合约abi
    var contractAbi = [{"constant":true,"inputs":[],"name":"mintingFinished","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_value","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"cap","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"unpause","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_amount","type":"uint256"}],"name":"mint","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_value","type":"uint256"}],"name":"burn","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"paused","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_subtractedValue","type":"uint256"}],"name":"decreaseApproval","outputs":[{"name":"success","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"balance","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"finishMinting","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"pause","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"owner","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_addedValue","type":"uint256"}],"name":"increaseApproval","outputs":[{"name":"success","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"},{"name":"_spender","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"newOwner","type":"address"}],"name":"transferOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"name":"burner","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Burn","type":"event"},{"anonymous":false,"inputs":[],"name":"Pause","type":"event"},{"anonymous":false,"inputs":[],"name":"Unpause","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"to","type":"address"},{"indexed":false,"name":"amount","type":"uint256"}],"name":"Mint","type":"event"},{"anonymous":false,"inputs":[],"name":"MintFinished","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"owner","type":"address"},{"indexed":true,"name":"spender","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"from","type":"address"},{"indexed":true,"name":"to","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Transfer","type":"event"}];
    
    // 合约地址
    var contractAddress = "0x7FCCF800568747b178c6cBbe4Bf3d147df75ac61";
    
    // 账号
    var currentAccount = "0x4e9d5c58d8d6f02FFe5A6EF10CB804FfFB556bBb";
    
    // 定义合约
    var myContract = new web3.eth.Contract(contractAbi, contractAddress, {
        from: currentAccount, // default from address
        gasPrice: '10000000000' // default gas price in wei, 10 gwei in this case
    });
    
    // 查询以太币余额
    web3.eth.getBalance(currentAccount).then(console.log);
    
    // 查看某个账号的代币余额
    myContract.methods.balanceOf(contractAddress).call({from: currentAccount}, function(error, result){
        if(!error) {
            console.log(result);
        } else {
            console.log(error);
        }
    });

举一反三，这里还可以查询代币的名称，符号，小数位，发行总量等等，因为代币合约一般都符合`ERC`标准，都有这些基本方法。甚至如果你有合约代码和`abi`，还可以调用合约的其他方法，当然调用有些方法需要权限及前置条件。

// 获得代币名称
    myContract.methods.name().call({from: currentAccount}, function(error, result){
        if(!error) {
              console.log(result);
        } else {
          console.log(error);
        }
    });
    
    // 获取代币符号
    myContract.methods.symbol().call({from: currentAccount}, function(error, result){
        if(!error) {
          console.log(result);
         } else {
          console.log(error);
         }
    });
    
    // 获取代币总量
    myContract.methods.totalSupply().call({from: currentAccount}, function(error, result){
        if(!error) {
          console.log(result);
         } else {
          console.log(error);
         }
    });
    
    // 查看某个账号允许另一个账号可使用的代币数量
    myContract.methods.allowance(sender, spender).call({from: currentAccount}, function(error, result){
        if(!error) {
          console.log(result);
         } else {
          console.log(error);
         }
    });

## 2.2 在私链上转账以太币及代币 ##

// 以太币转账
    web3.eth.sendTransaction({
        from: currentAccount,
        to: receiverAccount,
        value: '1000000000000000'
    })
    .then(function(receipt){
        console.log(receipt);
    });
    
    // 代币转账
    myContract.methods.transfer(to, amount).send({from: currentAccount}), function(error, transactionHash){
        if(!error) {
           console.log('transactionHash is ' + transactionHash);
        } else {
           console.log(error);
        }
    });

## 2.2 在主链上转账以太币及代币 ##

上面的方法只适用于私链。因为你在私链的账户在本地是有私钥的。而在主链上要进行写入数据的方法，是需要获取账户的私钥并对交易进行签名的，所以要用到`web3.eth.sendSignedTransaction`方法。

文档[http://web3js.readthedocs.io/en/1.0/web3-eth.html\#sendsignedtransaction][http_web3js.readthedocs.io_en_1.0_web3-eth.html_sendsignedtransaction]

> 方法稍微有点复杂，建议先查看底部的参考文章。因为有些重复的内容这里就不再解释了。

需要`npm`安裝'ethereumjs-tx'

npm install ethereumjs-tx

以太币转账

// 引入ethereumjs-tx
    var Tx = require('ethereumjs-tx');
    
    // 以太币转账    
    // 先获取当前账号交易的nonce
    web3.eth.getTransactionCount(currentAccount, web3.eth.defaultBlock.pending).then(function(nonce){
    
        
        // 获取交易数据
        var txData = {
            // nonce每次++，以免覆盖之前pending中的交易
            nonce: web3.utils.toHex(nonce++),
            // 设置gasLimit和gasPrice
            gasLimit: web3.utils.toHex(99000),   
            gasPrice: web3.utils.toHex(10e9),  
            // 要转账的哪个账号  
            to: '0x3b11f5CAB8362807273e1680890A802c5F1B15a8',
            // 从哪个账号转
            from: currentAccount,
            // 0.001 以太币
            value: web3.utils.toHex(10e14),         
            data: ''
        }
    
        var tx = new Tx(txData);
    
        // 引入私钥，并转换为16进制
        const privateKey = new Buffer('your account privateKey', 'hex'); 
    
        // 用私钥签署交易
        tx.sign(privateKey);
    
        // 序列化
        var serializedTx = tx.serialize().toString('hex');
    
        web3.eth.sendSignedTransaction('0x' + serializedTx.toString('hex'), function(err, hash) {
            if (!err) {
                console.log(hash);
            } else {
                console.error(err);
            }
        });
    });

代币转账

// 补齐64位，不够前面用0补齐
    function addPreZero(num){
      var t = (num+'').length,
      s = '';
      for(var i=0; i<64-t; i++){
        s += '0';
      }
      return s+num;
    }
    
    web3.eth.getTransactionCount(currentAccount, web3.eth.defaultBlock.pending).then(function(nonce){
    
        // 获取交易数据
        var txData = {
            nonce: web3.utils.toHex(nonce++),
            gasLimit: web3.utils.toHex(99000),   
            gasPrice: web3.utils.toHex(10e9),
            // 注意这里是代币合约地址    
            to: contractAddress,
            from: currentAccount,
            // 调用合约转账value这里留空
            value: '0x00',         
            // data的组成，由：0x + 要调用的合约方法的function signature + 要传递的方法参数，每个参数都为64位(对transfer来说，第一个是接收人的地址去掉0x，第二个是代币数量的16进制表示，去掉前面0x，然后补齐为64位)
            data: '0x' + 'a9059cbb' + addPreZero('3b11f5CAB8362807273e1680890A802c5F1B15a8') + addPreZero(web3.utils.toHex(1000000000000000000).substr(2))
        }
    
        var tx = new Tx(txData);
    
        const privateKey = new Buffer('your account privateKey', 'hex'); 
    
        tx.sign(privateKey);
    
        var serializedTx = tx.serialize().toString('hex');
    
        web3.eth.sendSignedTransaction('0x' + serializedTx.toString('hex'), function(err, hash) {
            if (!err) {
                console.log(hash);
            } else {
                console.error(err);
            }
        });
    });

[http_web3js.readthedocs.io_en_1.0]: http://web3js.readthedocs.io/en/1.0/
[700]: /images/20220519/38167fd1105f430aa9aa33ec67fa2a9d.png
[https_github.com_ethereum_wiki_wiki_JavaScript-API]: https://github.com/ethereum/wiki/wiki/JavaScript-API
[Link 1]: https://blog.csdn.net/ffzhihua/article/details/81127007
[https_github.com_ethereum_web3.js]: https://github.com/ethereum/web3.js
[https_etherscan.io]: https://etherscan.io/
[http_web3js.readthedocs.io_en_1.0_web3-eth.html_sendsignedtransaction]: http://web3js.readthedocs.io/en/1.0/web3-eth.html#sendsignedtransaction