基于以太坊truffle框架实践去中心化竞标商城(一)

前言:
truffle:是一个基于以太坊快速开发智能合约的框架,省去了很多基础文件及基础代码的构建。官方还有宠物商城等等案例代码。
官方地址:http://truffleframework.com/

操作环境:阿里云的centos 7.0 (windows下试过,但是报错更加离谱)

先啰嗦一下我的观点,原本我以为truffle只是一个部署智能合约的框架,如果只能编写并部署智能合约,那其实用ethereum wallet客户端就可以直接编辑和部署了,相信很多刚入门的小伙伴也会有同样的困惑。truffle不仅仅是编写智能合约,还结合了具体应用,比如:web,可以真真切切的开发以太坊的落地应用。

好,搬好小板凳,准备好你的番茄闹钟,步骤实践约需要1个小时(前提是你的私链环境已搭建ok):

一、预热准备

1、安装nodejs,官网下载;
2、安装truffle框架

npm -g truffle

3、搭建以太坊私链环境
参见我之前的文章:https://www.jianshu.com/p/52332fa4a24c

二、初始化truffle webpack项目

命令:

//创建项目目录
mkdir Ebay
cd Ebay
truffle unbox webpack //这个时候会自动开始下载项目初始化代码

结果如下:


基于以太坊truffle框架实践去中心化竞标商城(一)_第1张图片
image.png
三、编写智能合约代码
cd contracts
rm -rf MetaCoin.sol //该文件用不到,删除掉即可
vi EbayStore.sol

代码如下:

pragma solidity ^0.4.18;
contract EbayStore{
uint public productIndex;
function EbayStore() public{
    productIndex =0;
}
enum ProductStatus{
    Open,Sold,Unsold
}
enum ProductCondition{
    New,Used
}

mapping(address=>mapping(uint=>Product)) stores;
mapping(uint=>address) productIdInStore;

struct Product{
    uint id;
    string name;
    string category;//分类
    string imageLink;
    string descLink;
    uint auctionStartTime; //开始竞标时间
    uint auctionEndTime; //结束竞标时间
    uint startPrice;//拍卖价格
    address highestBidder;//赢家的钱包地址
    uint highestBid; //竞标的价格
    address secondHighestBidder; //第二高出价人的钱包地址
    uint totalBids; //总共多少人参与竞标
    ProductStatus status;
    ProductCondition condition;
    // mapping(address => mapping(bytes32 => Bid)) bids;
}
function addProductToStore(string _name, string _category, string _imageLink, string _descLink, uint _auctionStartTime, uint _auctionEndTime, uint _startPrice, uint _productCondition) public{
    require(_auctionStartTime < _auctionEndTime);
    productIndex ++;
    Product memory product = Product(productIndex, _name, _category, _imageLink, _descLink, _auctionStartTime, _auctionEndTime, _startPrice, 0, 0, 0, 0, ProductStatus.Open, ProductCondition(_productCondition));
    stores[msg.sender][productIndex] = product;
    productIdInStore[productIndex] = msg.sender;
}
function getProduct(uint _productId) view public returns(uint,string,string,string,string,uint,uint,uint,ProductStatus,ProductCondition){
    Product memory product = stores[productIdInStore[_productId]][_productId];
    return (product.id, product.name, product.category, product.imageLink, product.descLink, product.auctionStartTime, product.auctionEndTime, product.startPrice, product.status, product.condition);  
}
}
四、启动以太坊节点及RPC

启动命令如下:

./geth --datadir "./chain" --rpcapi "db,eth,net,web3,personal,admin,miner" --nodiscover console 2>>eth_output.log
> admin.startRPC() //启动RPC,该方法有多种,还可以在第一句命令上加上rpc启动命令
五、编译和部署智能合约

在刚才的Ebay目录下进入truffle开发控制台:

truffle develop
truffle(develop)> compile  //编译智能合约,生成的文件会自动写到build/contracts目录
Compiling ./contracts/EbayStore.sol...

Compilation warnings encountered:

/opt/go-ethereum/ethereum/truffle/Ebay/contracts/EbayStore.sol:4:2: Warning: Defining constructors as functions with the same name as the contract is deprecated. Use "constructor(...) { ... }" instead.
    function EbayStore() public{
 ^ (Relevant source part starts here and spans across multiple lines).

Writing artifacts to ./build/contracts

再进行部署合约:

truffle(develop)> migrate
Using network 'develop'.

Running migration: 1_initial_migration.js
Deploying Migrations...
 ... 0x9703f0bcfbea1379917db408adaa99bc708a5a8a4f3a48375ef39bda5e9436b6
Migrations: 0x8cdaf0cd259887258bc13a92c0a6da92698644c0
Saving successful migration to network...
... 0xd7bc86d31bee32fa3988f1c1eabce403a1b5d570340a3a9cdba53a472ee8c956
Saving artifacts...
Running migration: 2_deploy_contracts.js
Deploying EbayStore...
... 0x4ff35a0843e9a3c9df51963e90212830a1f663ecba21721798880111ee6a5161
EbayStore: 0x345ca3e014aaf5dca488057592ee47305d9b3e10
Saving successful migration to network...
... 0xf36163615f41ef7ed8f4a8f192149a0bf633fe1a2398ce001bf44c43dc7bdda0
Saving artifacts...
六、遇到的问题(解决问题占用时间的2/3):
1、启动geth的时候不能启动/无反应或一下提示

fatal error: runtime: out of memory

top查看占用内存最多的进程,并且把不用的删除掉

2、truffle在部署migrate的时候,提示geth客户端没有启动/没有启动rpc/没有配置好truffle.js

首先一个个来做:
启动geth(第二种方式同时启动geth和rpc):

./geth --datadir "./chain" --rpc --rpcapi "db,eth,net,web3,personal,admin,miner" --nodiscover console 2>>eth_output.log

更改Ebay项目下的truffle.js文件

require('babel-register')

module.exports = {
  networks: {
    development: {
      host: '127.0.0.1',
      port: 8545, //该端口是默认的rpc监听端口
      network_id: '*' // Match any network id
    }
  }
}
3、migrate报错

Running migration: 1_initial_migration.js
Could not connect to your Ethereum client. Please check that your Ethereum client:
- is running
- is accepting RPC connections (i.e., "--rpc" option is used in geth)
- is accessible over the network
- is properly configured in your Truffle configuration file (truffle.js)

解决办法:
重启,然后先启动私链,再启动truffle develop

4、truffle compile 时而好时而不好

解决办法:reboot

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