0. 背景
上一篇文章我们从合约编写、编译、部署、交互等几个方面介绍了truffle的大致用法。
本篇主要继续深入地介绍truffle的高级用法 + 合约源码分析
1. 将合约部署到测试网Ropsten
1.1 注册infura获取API-KEY
infura是基于ETH的chain公共API服务，为开发者提供链上数据查询、交易广播等功能。
1.2 准备助记词
可从Web钱包MetaMask 上进行创建并导出助记词
注一个助记词可以对应多个网络环境的地址，请勿向助记词对应的地址转入主网的ETH,否则有一定的安全风险
1.3 安装truffle-hdwallet-provider
由于需要将合约部署到测试网Ropsten，此过程需要部署者私钥进行签名再将数据进行广播，truffle-hdwallet-provider是truffle上提供交易离线签名的模块
注：必须在truffle框架的代码目录下安装，否则不生效
✘ wujinquan@wujinquandeMacBook-Pro ~/workspace/eth/truffle/defi npm install truffle-hdwallet-providernpm WARN deprecated truffle-hdwallet-provider@1.0.17: WARNING: This package has been renamed to @truffle/hdwallet-provider.npm WARN deprecated request@2.88.2: request has been deprecated, see /request/request/issues/3142> websocket@1.0.29 install /Users/wujinquan/workspace/eth/truffle/defi/node_modules/web3-providers-ws/node_modules/websocket> (node-gyp rebuild 2> builderror.log) || (exit 0)CXX(target) Release/obj.target/bufferutil/src/bufferutil.o> websocket@1.0.31 install /Users/wujinquan/workspace/eth/truffle/defi/node_modules/websocket> (node-gyp rebuild 2> builderror.log) || (exit 0)CXX(target) Release/obj.target/bufferutil/src/bufferutil.oSOLINK_MODULE(target) Release/bufferutil.nodeCXX(target) Release/obj.target/validation/src/validation.oSOLINK_MODULE(target) Release/validation.nodenpm WARN saveError ENOENT: no such file or directory, open '/Users/wujinquan/workspace/eth/truffle/defi/package.json'npm notice created a lockfile as package-lock.json. You should commit this file.npm WARN enoent ENOENT: no such file or directory, open '/Users/wujinquan/workspace/eth/truffle/defi/package.json'npm WARN defi No descriptionnpm WARN defi No repository field.npm WARN defi No README datanpm WARN defi No license field.+ truffle-hdwallet-provider@1.0.17added 326 packages from 212 contributors and audited 20646 packages in 114.122sfound 2 vulnerabilities (1 low, 1 high)run `npm audit fix` to fix them, or `npm audit` for details╭────────────────────────────────────────────────────────────────╮│ ││New minor version of npm available! 6.13.4 → 6.14.2 ││ Changelog: /npm/cli/releases/tag/v6.14.2 ││Run npm install -g npm to update!││ │╰────────────────────────────────────────────────────────────────╯wujinquan@wujinquandeMacBook-Pro ~/workspace/eth/truffle/defi lsbuild defi node_modulestestcontracts migrations package-lock.json truffle-config.jswujinquan@wujinquandeMacBook-Pro ~/workspace/eth/truffle/defi
1.4 修改truffle配置
主要修改ropsten网络配置，使truffle能顺利与ropsten交互
/*** Use this file to configure your truffle project. It's seeded with some* common settings for different networks and features like migrations,* compilation and testing. Uncomment the ones you need or modify* them to suit your project as necessary.** More information about configuration can be found at:** /docs/advanced/configuration** To deploy via Infura you'll need a wallet provider (like @truffle/hdwallet-provider)* to sign your transactions before they're sent to a remote public node. Infura accounts* are available for free at: infura.io/register.** You'll also need a mnemonic - the twelve word phrase the wallet uses to generate* public/private key pairs. If you're publishing your code to GitHub make sure you load this* phrase from a file you've .gitignored so it doesn't accidentally become public.**/const HDWalletProvider = require("truffle-hdwallet-provider");// const infuraKey = "fj4jll3k.....";//// const fs = require('fs');// const mnemonic = fs.readFileSync(".secret").toString().trim();const mnemonic = "grant boat distance require trap pair theme together spray blush glory simple"//0x843ACfB41E5c0F1E0587C5B765d897cCDeA8c4DDmodule.exports = {/*** Networks define how you connect to your ethereum client and let you set the* defaults web3 uses to send transactions. If you don't specify one truffle* will spin up a development blockchain for you on port 9545 when you* run `develop` or `test`. You can ask a truffle command to use a specific* network from the command line, e.g** $ truffle test --network <network-name>*/networks: {// Useful for testing. The `development` name is special - truffle uses it by default// if it's defined here and no other network is specified at the command line.// You should run a client (like ganache-cli, geth or parity) in a separate terminal// tab if you use this network and you must also set the `host`, `port` and `network_id`// options below to some value.//// development: {// host: "127.0.0.1",// Localhost (default: none)// port: 8545, // Standard Ethereum port (default: none)// network_id: "*", // Any network (default: none)// },// Another network with more advanced options...// advanced: {// port: 8777, // Custom port// network_id: 1342, // Custom network// gas: 8500000, // Gas sent with each transaction (default: ~6700000)// gasPrice: 20000000000, // 20 gwei (in wei) (default: 100 gwei)// from: <address>, // Account to send txs from (default: accounts[0])// websockets: true // Enable EventEmitter interface for web3 (default: false)// },// Useful for deploying to a public network.// NB: It's important to wrap the provider as a function.ropsten: {provider: () => new HDWalletProvider(mnemonic, `https://ropsten.infura.io/v3/5c93axxx`),//示例无效network_id: 3, // Ropsten's idgas: 5500000, // Ropsten has a lower block limit than mainnetconfirmations: 2, // # of confs to wait between deployments. (default: 0)timeoutBlocks: 200, // # of blocks before a deployment times out (minimum/default: 50)skipDryRun: true// Skip dry run before migrations? (default: false for public nets )}// Useful for private networks// private: {// provider: () => new HDWalletProvider(mnemonic, `https://network.io`),// network_id: 2111, // This network is yours, in the cloud.// production: true // Treats this network as if it was a public net. (default: false)// }},// Set default mocha options here, use special reporters etc.mocha: {// timeout: 100000},// Configure your compilerscompilers: {solc: {// version: "0.5.1", // Fetch exact version from solc-bin (default: truffle's version)// docker: true, // Use "0.5.1" you've installed locally with docker (default: false)// settings: {// See the solidity docs for advice about optimization and evmVersion// optimizer: {// enabled: false,// runs: 200// },// evmVersion: "byzantium"// }}}}
1.5 部署至Ropsten
执行truffle migrate --network ropsten --reset即可部署至Ropsten
如需要重新编译所有合约，可执行truffle migrate --network ropsten --reset --compile-all
wujinquan@wujinquandeMacBook-Pro ~/workspace/eth/truffle/defi truffle migrate --network ropsten --resetCompiling your contracts...===========================> Everything is up to date, there is nothing to compile.Starting migrations...======================> Network name: 'ropsten'> Network id:3> Block gas limit: 0x7a121d1_initial_migration.js======================Replacing 'Migrations'----------------------> transaction hash: 0x349ca58d8ed2176265efc58bf232878d930c71436a9b39796062489a638de396> Blocks: 2 Seconds: 92> contract address: 0x619DB4dda0cd2b3fF6351F52828Af5Cc44E6cA55> block number: 7531302> block timestamp:1584376631> account: 0x843ACfB41E5c0F1E0587C5B765d897cCDeA8c4DD> balance: 0.47030684> gas used: 164175> gas price: 20 gwei> value sent:0 ETH> total cost:0.0032835 ETHPausing for 2 confirmations...------------------------------> confirmation number: 1 (block: 7531303)> confirmation number: 3 (block: 7531305)> Saving migration to chain.> Saving artifacts-------------------------------------> Total cost: 0.0032835 ETH2_deploy_contracts.js=====================Replacing 'DeFi'----------------> transaction hash: 0x4be50b4e7a560080de6587078f937a553f29ac7b04ccd2e6b3802dc75dc8fe61> Blocks: 1 Seconds: 63> contract address: 0xB378420cde84c7A73EecfAeE2fC91ED364F45E9F> block number: 7531309> block timestamp:1584376852> account: 0x843ACfB41E5c0F1E0587C5B765d897cCDeA8c4DD> balance: 0.4474762> gas used: 1099191> gas price: 20 gwei> value sent:0 ETH> total cost:0.02198382 ETHPausing for 2 confirmations...------------------------------> confirmation number: 1 (block: 7531310)> confirmation number: 2 (block: 7531311)> Saving migration to chain.> Saving artifacts-------------------------------------> Total cost:0.02198382 ETHSummary=======> Total deployments: 2> Final cost:0.02526732 ETHwujinquan@wujinquandeMacBook-Pro ~/workspace/eth/truffle/defi
1.6 从区块浏览器上查看已部署的合约
从log输出可见DeFi合约地址为0xB378420cde84c7A73EecfAeE2fC91ED364F45E9F
2. 合约源码分析
项目源码可见Github仓库，主要分析DeFi.sol,过程以下代码中的详细中英文注释
pragma solidity >=0.4.25 <0.7.0;contract Token{mapping (address => uint256) balances;string public name;string public symbol;uint8 public decimals;uint256 public totalSupply;mapping (address => mapping (address => uint256)) allowed;//ERC20 Token Standard: /EIPS/eip-20constructor() public {name = "Token"; // Set the name symbol = "TK";// Set the symbol decimals = 18;// Amount of decimals for display purposes//totalSupply = 1000000000000000000000; // Not set total supply}//Returns the account balance of another account with address _owner.function balanceOf(address _owner) public view returns (uint256 balance) {return balances[_owner];}/* Transfers _value amount of tokens to address _to, and MUST fire the Transfer event. The function SHOULD throw if the message caller’s account balance does not have enough tokens to spend.Note Transfers of 0 values MUST be treated as normal transfers and fire the Transfer event.*/function transfer(address _to, uint256 _value) public returns (bool success) {require(_value > 0 ); // Check if token's value to be send > 0require(balances[msg.sender] >= _value); // Check if the sender has enough tokenrequire(balances[_to] + _value > balances[_to]); // Check for overflowsbalances[msg.sender] -= _value; // Subtract token from the senderbalances[_to] += _value;// Add the same amount to the receiver emit Transfer(msg.sender, _to, _value); // Notify anyone listening that this transaction happen.return true;}/* The transferFrom method is used for a withdraw workflow, allowing contracts to transfer tokens on your behalf. This can be used for example to allow a contract to transfer tokens on your behalf and/or to charge fees in sub-currencies. The function SHOULD throw unless the _from account has deliberately authorized the sender of the message via some mechanism.Note Transfers of 0 values MUST be treated as normal transfers and fire the Transfer event.*/function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {require(balances[_from] >= _value); // Check if the sender has enough tokenrequire(balances[_to] + _value >= balances[_to]); // Check for overflowsrequire(_value <= allowed[_from][msg.sender]);// Check allowancebalances[_from] -= _value;// Subtract from the senderbalances[_to] += _value; // Add the same amount to the receiverallowed[_from][msg.sender] -= _value;emit Transfer(_from, _to, _value);return true;}/* Allows _spender to withdraw from your account multiple times, up to the _value amount. If this function is called again it overwrites the current allowance with _value.NOTE: To prevent attack vectors like the one described here and discussed here, clients SHOULD make sure to create user interfaces in such a way that they set the allowance first to 0 before setting it to another value for the same spender. THOUGH The contract itself shouldn’t enforce it, to allow backwards compatibility with contracts deployed before */function approve(address _spender, uint256 _value) public returns (bool success) {require(balances[msg.sender] >= _value);allowed[msg.sender][_spender] = _value;emit Approval(msg.sender, _spender, _value);return true;}//Returns the amount which _spender is still allowed to withdraw from _owner.function allowance(address _owner, address _spender) public view returns (uint256 remaining) {return allowed[_owner][_spender];}//The event for tranfer and approveevent Transfer(address indexed _from, address indexed _to, uint256 _value);event Approval(address indexed _owner, address indexed _spender, uint256 _value);}contract DeFi is Token{//声明owner，暂时没作用address public owner ;//声明 用户-抵押ETH数量 mappingmapping (address => uint) pledgeETHAmount;//声明 抵押/赎回时的eventevent Pledge(address user, uint256 amount);event Redeem(address user, uint256 amount);//构造函数，只在合约被部署的时候执行一次constructor() public {owner = msg.sender ;}//抵押功能function pledge() public payable returns(bool success){//ETH抵押金额必须大于0require(msg.value > 0, "Not enough ETH to pledge.");//抵押操作// 1. 1:1贷出ERC20 TokenToken.balances[msg.sender] += msg.value;// 2. 写入抵押信息map，记录用户抵押ETH的数量：单位weipledgeETHAmount[msg.sender] += msg.value;// 3. 更新Token总量Token.totalSupply += msg.value;//记录抵押事件emit Pledge(msg.sender,msg.value);return true;}//赎回功能function redeem(uint256 value) public returns(bool success){//要求赎回ETH的数量必须 <= Token余额require(value <= Token.balances[msg.sender],"Not enough ETH to redeem.");//赎回操作// 1. 在合约转出ETH到用户地址之前将待发金额清零，更新用户Token余额和Token总量，来防止重入（re-entrancy）攻击Token.balances[msg.sender] -= value;Token.totalSupply -= value;// 2. 从合约里转ETH到对应用户msg.sender.transfer(value);//记录赎回事件emit Redeem(msg.sender,value);return true;}}
3. 与合约交互
在项目目录中执行truffle console --network ropsten连接ropsten并进入console模式
3.0 定义常用的抽象合约对象
truffle(ropsten)> let defi = await DeFi.deployed() //合约对象定义为defiundefinedtruffle(ropsten)> let contractaddr = await defi.address 合约地址定义为contractaddrundefinedtruffle(ropsten)>
3.1 调用合约抵押ETH贷出ERC20代币TK
可见区块浏览器https://ropsten.etherscan.io/tx/0x6dcb3790976b0d3a6f0715739a3c771f192f39b3f1d2995a88f718d6df30c6d9
truffle(ropsten)> defi.pledge.sendTransaction({from:accounts[0],value:101}) //指定sender和抵押ETH数量，回显需要一点时间{tx: '0x6dcb3790976b0d3a6f0715739a3c771f192f39b3f1d2995a88f718d6df30c6d9',receipt: {blockHash: '0x15b79d45581d83e7f5aaa40a9fac51c13d1824f188869207948c050fc4ded8ae',blockNumber: 7531333,contractAddress: null,cumulativeGasUsed: 85311,from: '0x843acfb41e5c0f1e0587c5b765d897ccdea8c4dd',gasUsed: 85311,logs: [ [Object] ],logsBloom: '0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000200000000000000000000000000000000000040000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000',status: true,to: '0xb378420cde84c7a73eecfaee2fc91ed364f45e9f',transactionHash: '0x6dcb3790976b0d3a6f0715739a3c771f192f39b3f1d2995a88f718d6df30c6d9',transactionIndex: 0,rawLogs: [ [Object] ]},logs: [{address: '0xB378420cde84c7A73EecfAeE2fC91ED364F45E9F',blockHash: '0x15b79d45581d83e7f5aaa40a9fac51c13d1824f188869207948c050fc4ded8ae',blockNumber: 7531333,logIndex: 0,removed: false,transactionHash: '0x6dcb3790976b0d3a6f0715739a3c771f192f39b3f1d2995a88f718d6df30c6d9',transactionIndex: 0,id: 'log_818726e7',event: 'Pledge',args: [Result]}]}truffle(ropsten)>
3.2 查询合约余额和用户的Token余额是否达到预期
truffle(ropsten)> web3.eth.getBalance(contractaddr) //合约的ETH余额'101'truffle(ropsten)> defi.balanceOf(accounts[0]) //用户的Token余额BN {negative: 0,words: [ 101, <1 empty item> ],length: 1,red: null}truffle(ropsten)>
3.3 调用合约归还ERC20代币TK，赎回ETH
可见区块浏览器https://ropsten.etherscan.io/tx/0xa720d3da5eda30b9a816e68aaf41ddde0a536c2307734317f6b15243fb9b1829
truffle(ropsten)> defi.redeem.sendTransaction(99,{from:accounts[0]}) //归还99`TK`,1比1 赎回99`wei`的`ETH`Error: Invalid JSON RPC response: ""at Object.InvalidResponse (/Users/wujinquan/workspace/eth/truffle/defi/node_modules/truffle-hdwallet-provider/dist/webpack:/truffle-hdwallet-provider/Users/gnidan/src/work/truffle/node_modules/web3/node_modules/web3-core-helpers/src/errors.js:42:1)at t.InvalidResponse [as onreadystatechange] (/Users/wujinquan/workspace/eth/truffle/defi/node_modules/truffle-hdwallet-provider/dist/webpack:/truffle-hdwallet-provider/Users/gnidan/src/work/truffle/node_modules/web3/node_modules/web3-providers-http/src/index.js:92:1)at t._a [as dispatchEvent] (/Users/wujinquan/workspace/eth/truffle/defi/node_modules/truffle-hdwallet-provider/dist/webpack:/truffle-hdwallet-provider/Users/gnidan/src/work/truffle/node_modules/xhr2-cookies/dist/xml-http-request-event-target.js:27:61)at t.dispatchEvent [as _setReadyState] (/Users/wujinquan/workspace/eth/truffle/defi/node_modules/truffle-hdwallet-provider/dist/webpack:/truffle-hdwallet-provider/Users/gnidan/src/work/truffle/node_modules/xhr2-cookies/dist/xml-http-request.js:208:1)at t._setReadyState [as _onHttpRequestError] (/Users/wujinquan/workspace/eth/truffle/defi/node_modules/truffle-hdwallet-provider/dist/webpack:/truffle-hdwallet-provider/Users/gnidan/src/work/truffle/node_modules/xhr2-cookies/dist/xml-http-request.js:349:1)at ClientRequest._onHttpRequestError (/Users/wujinquan/workspace/eth/truffle/defi/node_modules/truffle-hdwallet-provider/dist/webpack:/truffle-hdwallet-provider/Users/gnidan/src/work/truffle/node_modules/xhr2-cookies/dist/xml-http-request.js:252:47)at ClientRequest.emit (events.js:305:20)at ClientRequest.EventEmitter.emit (domain.js:483:12)at TLSSocket.socketErrorListener (_http_client.js:423:9)at TLSSocket.emit (events.js:305:20)at TLSSocket.EventEmitter.emit (domain.js:483:12)at emitErrorNT (internal/streams/destroy.js:84:8)at processTicksAndRejections (internal/process/task_queues.js:84:21){tx: '0xa720d3da5eda30b9a816e68aaf41ddde0a536c2307734317f6b15243fb9b1829',receipt: {blockHash: '0x0a08ef737e0729f31a2bd428eb50273833f669ebfc95b622cdf405c67996ceef',blockNumber: 7531341,contractAddress: null,cumulativeGasUsed: 756933,from: '0x843acfb41e5c0f1e0587c5b765d897ccdea8c4dd',gasUsed: 43116,logs: [ [Object] ],logsBloom: '0x00000000000000000000080000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000040000000000000000000000000000000040000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000',status: true,to: '0xb378420cde84c7a73eecfaee2fc91ed364f45e9f',transactionHash: '0xa720d3da5eda30b9a816e68aaf41ddde0a536c2307734317f6b15243fb9b1829',transactionIndex: 1,rawLogs: [ [Object] ]},logs: [{address: '0xB378420cde84c7A73EecfAeE2fC91ED364F45E9F',blockHash: '0x0a08ef737e0729f31a2bd428eb50273833f669ebfc95b622cdf405c67996ceef',blockNumber: 7531341,logIndex: 1,removed: false,transactionHash: '0xa720d3da5eda30b9a816e68aaf41ddde0a536c2307734317f6b15243fb9b1829',transactionIndex: 1,id: 'log_2be7cb64',event: 'Redeem',args: [Result]}]}truffle(ropsten)>
3.4 查询赎回后合约余额和用户的Token余额是否达到预期
truffle(ropsten)> web3.eth.getBalance(contractaddr) //合约的ETH余额'2'truffle(ropsten)> defi.balanceOf(accounts[0]) //用户的Token余额BN {negative: 0, words: [ 2, <1 empty item> ], length: 1, red: null }truffle(ropsten)>
4.其它部署调试工具
对于开发者而言，可使用可视化工具Remix进行合约调试、部署
同一例子，详细参考以太坊ETH-智能合约开发-Remix使用
