使用`Truffle Box`来创建`Truffle工程`

mkdir pet-shop

编写和测试智能合约

创建文件contracts/Adoption.sol

pragma solidity ^0.4.17;

contract Adoption {
  address[16] public adopters;
  // 领养宠物
  function adopt(uint petId) public returns (uint) {
    require(petId >= 0 && petId <= 15);

    adopters[petId] = msg.sender;

    return petId;
  }
  // Retireving the adopters
  function getAdopters() public view returns (address[16]) {
    return adopters;
  }
}

编写测试代码,’test/TestAdoption.sol’

pragma solidity ^0.4.17;

import "truffle/Assert.sol";
import "truffle/DeployedAddresses.sol";
import "../contracts/Adoption.sol";

contract TestAdoption {
  Adoption adoption = Adoption(DeployedAddresses.Adoption());
  // Testing the adopt() function
  function testUserCanAdoptPet() public {
    uint returnedId = adoption.adopt(8);

    uint expected = 8;

    Assert.equal(returnedId, expected, "Adoption of pet ID 8 should be recorded.");
  }
  // Testing retrieval of all pet owners
  function testGetAdopterAddressByPetIdInArray() public {
    // Expected owner is this contract
    address expected = this;

    // Store adopters in memory rather than contract's storage
    address[16] memory adopters = adoption.getAdopters();

    Assert.equal(adopters[8], expected, "Owner of pet ID 8 should be recorded.");
  }
}

Assert.sol：单元测试的assert方法,具体查看
DeployedAddresses.sol: 执行truffle测试用例，truffle会部署一个新的合约用力到区块链中，这个合约用户获得被部署的合约

执行测试。

➜  pet-shop-tutorial truffle test
Using network 'development'.

Compiling ./contracts/Adoption.sol...
Compiling ./test/TestAdoption.sol...
Compiling truffle/Assert.sol...
Compiling truffle/DeployedAddresses.sol...

  TestAdoption
    ✓ testUserCanAdoptPet (197ms)
    ✓ testGetAdopterAddressByPetId (165ms)
    ✓ testGetAdopterAddressByPetIdInArray (333ms)

  3 passing (2s)

构建前端应用页面

打开/src/js/app.js，替换replace me代码段。

initWeb3

// Is there an injected web3 instance?
if (typeof web3 !== 'undefined') {
  App.web3Provider = web3.currentProvider;
} else {
  // If no injected web3 instance is detected, fall back to Ganache
  App.web3Provider = new Web3.providers.HttpProvider('http://localhost:7545');
}
web3 = new Web3(App.web3Provider);

判断web3实例是否存在(Mist或者MentaMask)，如果存在则返回实例，不存在就新建。

initContract

$.getJSON('Adoption.json', function(data) {
 // 获取合约文件并使用truffle-contract方法实例化
 var AdoptionArtifact = data;
 App.contracts.Adoption = TruffleContract(AdoptionArtifact);

 // 将智能合约实例加载到服务容器中，此处是web3Providers
 App.contracts.Adoption.setProvider(App.web3Provider);

 // 使用合约来获取和标记被领养的宠物
 return App.markAdopted();
});

markAdopted

var adoptionInstance;

App.contracts.Adoption.deployed().then(function(instance) {
  adoptionInstance = instance;

  return adoptionInstance.getAdopters.call();
}).then(function(adopters) {
  for (i = 0; i < adopters.length; i++) {
    if (adopters[i] !== '0x0000000000000000000000000000000000000000') {
      $('.panel-pet').eq(i).find('button').text('Success').attr('disabled', true);
    }
  }
}).catch(function(err) {
  console.log(err.message);
});

使用getAdopters方法获得所有被领养的宠物，并将对应领养按钮设为disable。

handleAdopt

var adoptionInstance;
web3.eth.getAccounts(function(error, accounts) {
  if (error) {
    console.log(error);
  }
// 获取当前账户
var account = accounts[0];

App.contracts.Adoption.deployed().then(function(instance) {
  adoptionInstance = instance;
  // Execute adopt as a transaction by sending account
  return adoptionInstance.adopt(petId, {from: account});
  }).then(function(result) {
    return App.markAdopted();
  }).catch(function(err) {
    console.log(err.message);
  });
});

运行web server

npm run dev

完整代码

pet-shop

issue

修改DAPP的index.html，将<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>替换为https://cdn.bootcss.com/jquery/1.12.4/jquery.min.js

区块链导论:以太坊DAPP（宠物店应用）

使用Truffle Box来创建Truffle工程