链上链下交互|链上链下交互以太坊Dapp接口开发链上链下交互以太坊Dapp接口开

主要是指的是用NodeJs调用提供接口供前端使用用户查询和转账
以太坊Dapp项目众筹项目功能需求

路人
- 查看所有众筹项目, 2 @ OK
- 根据众筹项目的address获取该众筹的详情 (参与人数/已筹金额/目标金额/结束时间/参与人数)，2.5 @ OK
- 参与众筹项目, 3 @ OK
众筹发起人
- 创建众筹, 1 @ OK
- 查看自己创建的众筹, 5 @ OK
- 发起付款请求, 6
众筹参与者
- 查看已参与的众筹项目, 4 @ OK
- 审批付款请求, 7
获取当前account @ OK

智能合约及测试

外部函数的调用
参与人如何保存自己已经参与的项目
1. 定义数据：
  
  // 用于保存参与者的所有参与的项目，每一个FundingFactory只有一个 contract PlayerToFundings {mapping(address => address[]) playersFundings; // 添加接口（在Funding的support中被调用） function joinFunding(address funding, address sender) public{ playersFundings[sender].push(funding); }// 查询接口（在FundingFactory中被调用） function getFundings(address sender) public view returns(address[] fundings){ // return msg.sender; returnplayersFundings[sender]; }}
  
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2. 把数据放到新的合约中PlayerToFundings。
  mapping(address => address[]) private playerToFunings;
  
  contract FundingFactory {PlayerToFundings playerToFundings; // 初始化PlayerToFundings合约 constructor() public { address playerToFundingsAddress = new PlayerToFundings(); playerToFundings = PlayerToFundings(playerToFundingsAddress); }// * 提供获取合约中数据的函数 function getPlayerFoundings() public view returns(address[]){ return playerToFundings.getFundings(msg.sender); }}
  
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3. 存数据：Funding support时候存数据
  
  contract Funding {// 在factory创建Funding时，把PlayerToFundings传进来。 constructor (string _projectName, uint _supportMoney, uint _goalMoney, PlayerToFundings _p2f,address _address) public { ... p2f = _p2f; }// * 调用p2f，把参与者参与的项目存到PlayerToFundings的mapping中 funtion support() public payable { ... players.push(msg.sender); p2f.joinFunding(address(this), msg.sender); } }
demo

pragma solidity ^0.4.17; contract PlayerToFundings {uint count = 100; function setFundingsCount(uint _count) public { count = _count; }function getFundingsCount() public view returns(uint){ return count; }}contract Factory {PlayerToFundings p2f; address[] public fundings; // function Test(address p2fAddress) public{ //p2f = PlayerToFundings(p2fAddress); // } function Factory() public{ address p2fAddress = new PlayerToFundings(); p2f = PlayerToFundings(p2fAddress); }function createFounding() public { address funding = new Funding(p2f); fundings.push(funding); }function setCount(uint count) public { p2f.setFundingsCount(count); }function getCount() public view returns(uint){ return p2f.getFundingsCount(); } }contract Funding { PlayerToFundings p2f; function Funding(PlayerToFundings _p2f) public{ p2f = _p2f; }function support() public { p2f.setFundingsCount(999); } }

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