基于以太坊的抽奖demo

操作系统：centos 7.6
当前目录：$HOME/workspace/

1. 安装 truffle

npm install -g truffle

2. 创建项目目录 eth-lottery

mkdir eth-lottery
cd eth-lottery

3. 初始化 truffle 项目，直接借用别人写好的react模版

truffle unbox react

4. 添加抽奖相关的合约

cd contracts
vim Lottery.sol

Lottery.sol

pragma solidity ^0.5.0;

contract Lottery {
        address payable public manager;
        address payable[] public playersSlice;
        mapping(address => bool) public playersMap;
        uint256 public round = 0;
        address payable public winner;

        constructor() public {
                manager = msg.sender;
        }   

        modifier onlyManager() {
                require(manager == msg.sender);
                _;  
        }   

        function play() public payable {
                require(msg.value == 1 ether);
                require(!playersMap[msg.sender]);
                playersMap[msg.sender] = true;
                playersSlice.push(msg.sender);
        }   

        function getBalance() public view returns(uint256) {
                return address(this).balance;
        }   

        function getPlayersSlice() public view returns(address payable[] memory) {
                return playersSlice;
        }   

        function getPlayersCnt() public view returns(uint256) {
                return playersSlice.length;
        }   

        function randomUInt256(uint256 seed) private view returns(uint256) {
                bytes memory v1 = abi.encodePacked(block.timestamp, block.difficulty, seed);
                bytes32 v2 = keccak256(v1);
                return uint256(v2);
        }   

        function calBonusAndIncome(uint256 balance) private pure returns(uint256, uint256) {
                uint256 bonus = balance * 9 / 10; 
                uint256 income = balance - bonus;
                return (bonus, income);
        }   

        function drawPrize() onlyManager public {
                uint256 len = playersSlice.length;
                require(len > 0); 
                uint256 idx = randomUInt256(len) % len;
                winner = playersSlice[idx];
                uint256 bonus;
                uint256 income;
                (bonus, income) = calBonusAndIncome(getBalance());
                manager.transfer(income);
                winner.transfer(bonus);
                ++round;
                for (uint256 i = 0; i < len; ++i) {
                        delete(playersMap[playersSlice[i]]);
                }
         }

        function withdrawPrize() onlyManager public {
                for (uint256 i = 0; i < playersSlice.length; ++i) {
                        address payable player = playersSlice[i];
                        delete(playersMap[player]);
                        player.transfer(1 ether);
                }
                delete(playersSlice);
        }
}

5. 把合约目录共享到remix-idx，进行调试，确保合约没有bug

remixd -s $HOME/workspace/eth-lottery/constacts --remix-ide http://remix.ethereum.org

remixd的安装

npm install remixd -g

7. 修改模版的部署文件

cd ../migrations
vim 2_deploy_contracts.js

2_deploy_contracts.js

var Lottery = artifacts.require("./Lottery.sol");

module.exports = function(deployer) {
	deployer.deploy(Lottery);
};

8. 选择节点
   8.1. 假如只是本机测试的话，可以安装一个ganache-cli，启动它，就会生成一个本地的测试节点和网络，部署在它上就好了。

ganache-cli安装

npm install -g ganache-cli

启动ganache-cli

ganache-cli

记住输出的助记词（ Mnemonic ）和监听节点

Mnemonic:      improve ripple network feature legal holiday always awkward seek enforce quick drip
...
...
Listening on 127.0.0.1:8545

8.2. 假如想部署外网，例如主网或者Ropsten测试网络，需要一个仿真节点。
infura有免费提供这个服务。上去它的官网 https://infura.io/ ，并注册，开启一个项目。这样就获得节点
9. 修改模版的配置文件
根据官方文档 http://truffleframework.com/docs/advanced/configuration 我们把网络添加到truffle-config.js

cd ..
vim truffle-config.js

truffle-config.js

const path = require("path");
const HDWalletProvider = require("truffle-hdwallet-provider")

module.exports = { 
        // See 
        // to customize your Truffle configuration!
        contracts_build_directory: path.join(__dirname, "client/src/contracts"),

        networks: {
                ropsten: {
                        provider: function() {
                                const mnemonic = 'inject stock easy learn repair fringe damage crawl cruise junior enable remember';
                                const endpoint = 'https://ropsten.infura.io/v3/ba7794faf4cd4b27894283a1ded74631';
                                return new HDWalletProvider(mnemonic, endpoint);
                        },  
                        network_id: '3',
                },  
                test: {
                        provider: function() {
                                const mnemonic = 'improve ripple network feature legal holiday always awkward seek enforce quick drip';
                                const endpoint = 'http://127.0.0.1:8545/';
                                return new HDWalletProvider(mnemonic, endpoint);
                        },  
                        network_id: '*',
                },  
        }   
};

帮记词和节点根据你们的配置，还要安装npm install truffle-hdwallet-provider模块

npm init
npm install truffle-hdwallet-provider --save

10. 编译合约

truffle compile

合约的abi等信息都会导出在 ./client/src/contracts/ 下
11. 部署合约
11.1. 部署在本地测试节点网络

truffle migrate --network test

输出结果

⚠️  Important ⚠️
If you're using an HDWalletProvider, it must be Web3 1.0 enabled or your migration will hang.


Starting migrations...
======================
> Network name:    'development'
> Network id:      1549381217260
> Block gas limit: 6721975


1_initial_migration.js
======================

   Deploying 'Migrations'
   ----------------------
   > transaction hash:    0x99fd7645bdb7db4f4e6ea803e281ca06af0f4a36fc059f78ab712389a9898fae
   > Blocks: 0            Seconds: 0
   > contract address:    0x27D8F0326C4C6C60b080B1b21b7EAcEd4FF467D6
   > account:             0xa9a981e813d6d6658738220dD5F2fAa078B62aFA
   > balance:             99.99430184
   > gas used:            284908
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.00569816 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.00569816 ETH


2_deploy_contracts.js
=====================

   Deploying 'Lottery'
   -------------------
   > transaction hash:    0x32a6518bd03ae38805a6a0cce25e502eefd294dd91243ae486606a21c1a91280
   > Blocks: 0            Seconds: 0
   > contract address:    0xc65c364Fa2E7C8C684834c726636DBFd19938825
   > account:             0xa9a981e813d6d6658738220dD5F2fAa078B62aFA
   > balance:             99.976873
   > gas used:            829408
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.01658816 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.01658816 ETH


Summary
=======
> Total deployments:   2
> Final cost:          0.02228632 ETH

11.2. 部署在ropsten测试网络

truffle migrate --network ropsten

输出结果

⚠️  Important ⚠️
If you're using an HDWalletProvider, it must be Web3 1.0 enabled or your migration will hang.


Starting migrations...
======================
> Network name:    'ropsten'
> Network id:      3
> Block gas limit: 8000029


1_initial_migration.js
======================

   Deploying 'Migrations'
   ----------------------
   > transaction hash:    0xb488e762a06315eca3eddc94e67cf73b34e8f5d50364f8ec503df0306a1c0b6f
   > Blocks: 0            Seconds: 4
   > contract address:    0x479cc2fA1cbE27d00e09fC3a477b08D42680f10C
   > account:             0xcf961578df24ECB997929dbA39F6a05bA14c6bAd
   > balance:             15.05442234499999
   > gas used:            284908
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.00569816 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.00569816 ETH


2_deploy_contracts.js
=====================

   Deploying 'Lottery'
   -------------------
   > transaction hash:    0xe5aed3122b0127d7e30919ec43d73df0b1ed2d71d0a591af12a091ccf7bc5c57
   > Blocks: 2            Seconds: 20
   > contract address:    0x8c2216C695836EF98cd0cE470e0c7e95d80b8f06
   > account:             0xcf961578df24ECB997929dbA39F6a05bA14c6bAd
   > balance:             15.03689750499999
   > gas used:            834208
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.01668416 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.01668416 ETH


Summary
=======
> Total deployments:   2
> Final cost:          0.02238232 ETH

部署得太慢得话，有一个gas的项，多费一点gas，部署可以快很多。
合约信息
https://ropsten.etherscan.io/address/0x8c2216C695836EF98cd0cE470e0c7e95d80b8f06
部署完，应该要在ropsten测试网络提交源码的，但是我用VPN连上也是提交不成功，人机检测还是不刷出来，所以算了。

12. 安装semantic-ui-css,semantic-ui-css

cd client
npm install semantic-ui-css --save
npm install semantic-ui-react --save

13. 修改原来react模版的文件
    我把项目上传到github了，就不写了。
    https://github.com/kyojre/eth-lottery
14. 启动demo

npm run start

15. 访问localhost:3000端口，测试demo