以太坊 Dapp 入门实战之同步到区块链

mahesh@projectblockchain:~$ brew tap ethereum/ethereummahesh@projectblockchain:~$ brew install ethereum

mahesh@projectblockchain:~$ sudo apt-get install software-properties-commonmahesh@projectblockchain:~$ sudo add-apt-repository -y ppa:ethereum/ethereummahesh@projectblockchain:~$ sudo apt-get updatemahesh@projectblockchain:~$ sudo apt-get install ethereum

mahesh@projectblockchain:~$ geth --rinkeby --syncmode "fast" --rpc --rpcapi db,eth,net,web3,personal --cache=1024  --rpcport 8545 --rpcaddr 127.0.0.1 --rpccorsdomain "*"

npm install -g truffle

mahesh@projectblockchain:~$ mkdir votingmahesh@projectblockchain:~$ cd votingmahesh@projectblockchain:~/voting$ npm install -g webpackmahesh@projectblockchain:~/voting$ truffle unbox webpackmahesh@projectblockchain:~/voting$ lsREADME.md               contracts               node_modules            test                    webpack.config.js       truffle.jsapp                     migrations              package.json            mahesh@projectblockchain:~/voting$ ls app/index.html  javascripts  stylesheetsmahesh@projectblockchain:~/voting$ ls contracts/ConvertLib.sol  MetaCoin.sol  Migrations.solmahesh@projectblockchain:~/voting$ ls migrations/1_initial_migration.js  2_deploy_contracts.js

mahesh@projectblockchain:~/voting$ ls contracts/Migrations.sol  Voting.sol

var Voting = artifacts.require("./Voting.sol");module.exports = function(deployer) {  deployer.deploy(Voting, ['Rama', 'Nick', 'Jose'], {gas: 6700000});};/* 如上所示，部署器的第一个参数是合约的名称，第二个参数是要传给构造器的参数。就这个例子而言，构造器只有一个参数，即包含候选项的数组。第三个参数是哈希表，指定为部署代码提供的燃料。燃料多少取决于合约的大小。*/

require('babel-register')module.exports = {  networks: {    development: {      host: 'localhost',      port: 8545,      network_id: '*',      gas: 470000    }  }}

// 引入页面的CSS。Webpack知道该怎么做。import "../stylesheets/app.css";
// 引入我们需要的库import { default as Web3} from 'web3';import { default as contract } from 'truffle-contract'
/* * 在编译和部署Voting合约时，truffle会将abi和部署地址 * 存在build目录下的json文件中。我们会用这个信息设置 * Voting抽象。之后会用这个抽象创建Voting合约的实例。 * 可以跟我们之前那篇文章中的index.js文件比较一下有什么差异 * https://gist.github.com/maheshmurthy/f6e96d6b3fff4cd4fa7f892de8a1a1b4#file-index-js */
import voting_artifacts from '../../build/contracts/Voting.json'
var Voting = contract(voting_artifacts);
let candidates = {"Rama": "candidate-1", "Nick": "candidate-2", "Jose": "candidate-3"}
window.voteForCandidate = function(candidate) {  let candidateName = $("#candidate").val();  try {    $("#msg").html("Vote has been submitted. The vote count will increment as soon as the vote is recorded on the blockchain. Please wait.")    $("#candidate").val("");
    /* Voting.deployed()返回合约的实例。在Truffle中     * 每次都会返回一个promise，所以有交易调用的地方     * 都要用then()     */    Voting.deployed().then(function(contractInstance) {      contractInstance.voteForCandidate(candidateName, {gas: 140000, from: web3.eth.accounts[0]}).then(function() {        let div_id = candidates[candidateName];        return contractInstance.totalVotesFor.call(candidateName).then(function(v) {          $("#" + div_id).html(v.toString());          $("#msg").html("");        });      });    });  } catch (err) {    console.log(err);  }}
$( document ).ready(function() {  if (typeof web3 !== 'undefined') {    console.warn("Using web3 detected from external source like Metamask")    // 用Mist/MetaMask的provider    window.web3 = new Web3(web3.currentProvider);  } else {    console.warn("No web3 detected. Falling back to http://localhost:8545. You should remove this fallback when you deploy live, as it's inherently insecure. Consider switching to Metamask for development. More info here: http://truffleframework.com/tutorials/truffle-and-metamask");    // fallback - use your fallback strategy (local node / hosted node + in-dapp id mgmt / fail)    window.web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));  }
  Voting.setProvider(web3.currentProvider);  let candidateNames = Object.keys(candidates);  for (var i = 0; i < candidateNames.length; i++) {    let name = candidateNames[i];    Voting.deployed().then(function(contractInstance) {      contractInstance.totalVotesFor.call(name).then(function(v) {        $("#" + candidates[name]).html(v.toString());      });    })  }});

<!DOCTYPE html><html><head>  <title>Hello World DApp</title>  <link href='https://fonts.googleapis.com/css?family=Open+Sans:400,700' rel='stylesheet' type='text/css'>  <link href='https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css' rel='stylesheet' type='text/css'></head><body class="container">  <h1>A Simple Hello World Voting Application</h1>  <div id="address"></div>  <div class="table-responsive">    <table class="table table-bordered">      <thead>        <tr>          <th>Candidate</th>          <th>Votes</th>        </tr>      </thead>      <tbody>        <tr>          <td>Rama</td>          <td id="candidate-1"></td>        </tr>        <tr>          <td>Nick</td>          <td id="candidate-2"></td>        </tr>        <tr>          <td>Jose</td>          <td id="candidate-3"></td>        </tr>      </tbody>    </table>    <div id="msg"></div>  </div>  <input type="text" id="candidate" />  <a href="#" onclick="voteForCandidate()" class="btn btn-primary">Vote</a></body><script src="https://cdn.rawgit.com/ethereum/web3.js/develop/dist/web3.js"></script><script src="https://code.jquery.com/jquery-3.1.1.slim.min.js"></script><script src="app.js"></script></html>

mahesh@projectblockchain:~/voting$ truffle consoletruffle(default)> web3.personal.newAccount('verystrongpassword')'0x95a94979d86d9c32d1d2ab5ace2dcc8d1b446fa1'truffle(default)> web3.eth.getBalance('0x95a94979d86d9c32d1d2ab5ace2dcc8d1b446fa1'){ [String: '0'] s: 1, e: 0, c: [ 0 ] }truffle(default)> web3.personal.unlockAccount('0x95a94979d86d9c32d1d2ab5ace2dcc8d1b446fa1', 'verystrongpassword', 15000)// 将'verystrongpassword'换成真正的好密码。// 账户默认是锁着的，在用于部署和跟区块链交互之前，要确认一下已经解锁了。

mahesh@projectblockchain:~/voting$ truffle consoletruffle(default)> Voting.deployed().then(function(contractInstance) {contractInstance.voteForCandidate('Rama').then(function(v) {console.log(v)})})// 几秒钟之后，应该可以见到下面这样的交易收据：{ blockHash: '0x7229f668db0ac335cdd0c4c86e0394a35dd471a1095b8fafb52ebd7671433156',blockNumber: 469628,contractAddress: null,........truffle(default)> Voting.deployed().then(function(contractInstance) {contractInstance.totalVotesFor.call('Rama').then(function(v) {console.log(v)})}){ [String: '1'] s: 1, e: 0, c: [ 1] }

mahesh@projectblockchain:~/voting$ npm run dev