昨天发布了关于自己学习区块链和DAPP的学习小结式的文章，朋友对我提了几点意见说：合约没有身份，一个人可以很多次的投票只要舍得花gas这是个刷票漏洞。
仔细想来是有点偷懒了，所以今天补一篇。就两点：1，补上身份认证避免反复投票；2，对web3.0以及他的部署和调用再做一些介绍，其实功能和昨天是一样的但是方法会有所不同。
pragma solidity ^0.4.0;
contract Voting{
//投票列表
bytes32[] public candidateList;
//对应的票数
mapping(bytes32=>uint8) public votesReceived;
//投票人列表
mapping(address=>People) public Peoples;
//投票人信息及投票时间
struct People{
address account;
uint voingtime;
}
//构造投票列表
constructor(bytes32[] memory candidateListName) public{
candidateList = candidateListName;
}
//获取投票人账号
function getAccountAddress() public returns(uint32)
{
People memory people = Peoples[msg.sender];
return uint32(people.account);
}
//设置已投票地址
function setAccountAddress() private
{
People memory people = People(msg.sender,now);
Peoples[msg.sender] = people;
}
//判断投票信息是否在待投票列表
function valiCandidate(bytes32 candidateName) internal view returns(bool)
{
for(uint8 i=0;i<candidateList.length;i++)
{
if (candidateName==candidateList[i])
{
return true;
}
}
return false;
}
//对投票人增加投票
function voteForCandidate(bytes32 candidateName) public{
require(valiCandidate(candidateName));
//判断是否已投票 0 为未投票
require(getAccountAddress()==0);
setAccountAddress();
votesReceived[candidateName] = votesReceived[candidateName] + 1;
}
function totalVotesFor(bytes32 candidateName) view public returns(uint8){
require(valiCandidate(candidateName));
//返回票数
return votesReceived[candidateName];
}
}代码附上，具体可以看注释；其实很简单就是用mapping记录投票人地址（用struct记录）
mkdir web3.0
cd web3.0
npm init
一路回车初始化一个node js项目
npm install web3 -save
var Web3 = require('web3');
// 链接本地 ganache 记得启动
var web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));打开remix 我们可以看到web3的部署文件就这么简单
var web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
var candidateListName = ["0x4100000000000000000000000000000000000000000000000000000000000000","0x4200000000000000000000000000000000000000000000000000000000000000"] ;
var votingContract = new web3.eth.Contract([{"constant":false,"inputs":[],"name":"getAccountAddress","outputs":[{"name":"","type":"uint32"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"candidateName","type":"bytes32"}],"name":"totalVotesFor","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"Peoples","outputs":[{"name":"account","type":"address"},{"name":"voingtime","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"bytes32"}],"name":"votesReceived","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"uint256"}],"name":"candidateList","outputs":[{"name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"candidateName","type":"bytes32"}],"name":"voteForCandidate","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"inputs":[{"name":"candidateListName","type":"bytes32[]"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"}]);
var voting = votingContract.deploy({
data: '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',
arguments: [
candidateListName,
]
}).send({
//from: web3.eth.accounts[0],
from: '0xFFcf8FDEE72ac11b5c542428B35EEF5769C409f0',
gas: '4700000'
}, function (e, contract){
console.log(e, contract);
if (typeof contract.address !== 'undefined') {
console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
}
}).then(function(contract){
console.log('Contract ! address: ', contract.options.address);
});from: web3.eth.accounts[0], 记得改成你ganache个你的账号 现在通过node 部署 合约
node deploy.js
这时候你可以看到合约地址（Contract ! address: 0x32Cf1f3a98aeAF57b88b3740875D19912A522c1A）
下面是昨天APP项目调用合同的核心代码我直接在注释上写：
//node js 部署 我们没有这个json文件注释掉
// import votingArtifact from "../../build/contracts/Voting.json";
start: async function() {
const { web3 } = this;
try {
// get contract instance
const networkId = await web3.eth.net.getId();
//这里既然前面注释了，这里应该也没用了
const deployedNetwork = votingArtifact.networks[networkId];
//调用合同部分votingArtifact.abi这个哪里找呢？
//deployedNetwork.address 这个不就是合同地址吗
this.voting = new web3.eth.Contract(
votingArtifact.abi,
//deployedNetwork.address,
'0x32Cf1f3a98aeAF57b88b3740875D19912A522c1A',
);
// get accounts
const accounts = await web3.eth.getAccounts();
this.account = accounts[0];
this.ready();
this.refreshBalance();
} catch (error) {
console.error("Could not connect to contract or chain.");
}
},现在的问题votingArtifact.abi哪里找呢？
好吧原来remix里有复制下来 附上所有代码
import Web3 from "web3";
//import votingArtifact from "../../build/contracts/Voting.json";
const aInBytes32 ="0x4100000000000000000000000000000000000000000000000000000000000000";
const bInBytes32 ="0x4200000000000000000000000000000000000000000000000000000000000000";
const App = {
web3: null,
account: null,
meta: null,
start: async function() {
const { web3 } = this;
try {
// get contract instance
const networkId = await web3.eth.net.getId();
// const deployedNetwork = votingArtifact.networks[networkId];
// this.voting = new web3.eth.Contract(
// votingArtifact.abi,
// deployedNetwork.address,
// );
this.voting = new web3.eth.Contract(
[
{
"constant": false,
"inputs": [],
"name": "getAccountAddress",
"outputs": [
{
"name": "",
"type": "uint32"
}
],
"payable": false,
"stateMutability": "nonpayable",
"type": "function"
},
{
"constant": true,
"inputs": [
{
"name": "candidateName",
"type": "bytes32"
}
],
"name": "totalVotesFor",
"outputs": [
{
"name": "",
"type": "uint8"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": true,
"inputs": [
{
"name": "",
"type": "address"
}
],
"name": "Peoples",
"outputs": [
{
"name": "account",
"type": "address"
},
{
"name": "voingtime",
"type": "uint256"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": true,
"inputs": [
{
"name": "",
"type": "bytes32"
}
],
"name": "votesReceived",
"outputs": [
{
"name": "",
"type": "uint8"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": true,
"inputs": [
{
"name": "",
"type": "uint256"
}
],
"name": "candidateList",
"outputs": [
{
"name": "",
"type": "bytes32"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": false,
"inputs": [
{
"name": "candidateName",
"type": "bytes32"
}
],
"name": "voteForCandidate",
"outputs": [],
"payable": false,
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"name": "candidateListName",
"type": "bytes32[]"
}
],
"payable": false,
"stateMutability": "nonpayable",
"type": "constructor"
}
],
'0x32Cf1f3a98aeAF57b88b3740875D19912A522c1A',
);
// get accounts
const accounts = await web3.eth.getAccounts();
this.account = accounts[0];
this.ready();
this.refreshBalance();
} catch (error) {
console.error("Could not connect to contract or chain.");
}
},
ready:async function(){
try{
this.refresh("Alice",aInBytes32);
this.refresh("Bob",bInBytes32);
}catch(err){
console.log(err)
}
},
refresh:async function(id,nameBytes32){
const {totalVotesFor} = this.voting.methods;
const tickets = await totalVotesFor(nameBytes32).call();
const el = document.getElementById(id);
el.innerHTML = tickets.toString();
},
voteForCandidate:async function(){
try{
const {voteForCandidate} = this.voting.methods;
const condidateName = document.getElementById("candidate").value;
console.log(condidateName)
if (condidateName == "Alice")
{
await voteForCandidate(aInBytes32).send({from:this.account});
this.refresh("Alice",aInBytes32);
}
else{
await voteForCandidate(bInBytes32).send({from:this.account});
this.refresh("Bob",bInBytes32);
}
}catch(err){
console.log(err)
}
}
};
window.App = App;
window.addEventListener("load", function() {
if (window.ethereum) {
// use MetaMask's provider
App.web3 = new Web3(window.ethereum);
window.ethereum.enable(); // get permission to access accounts
} else {
console.warn(
"No web3 detected. Falling back to http://127.0.0.1:8545. You should remove this fallback when you deploy live",
);
// fallback - use your fallback strategy (local node / hosted node + in-dapp id mgmt / fail)
App.web3 = new Web3(
new Web3.providers.HttpProvider("http://127.0.0.1:8545"),
);
}
App.start();
});好了 程序都ok了 进入上次那个项目app目录（细节省略了）
cd app
npm run dev开始投票
第一次投票成功
第二次投票
好了不给投了，终于不能刷票了。
上次用的是脚手架一下子全好了，很多细节不到位，今天细一点也是对自己学习的终结。
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