链上链下交互 以太坊Dapp接口开发

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;
              return  playersFundings[sender];
          }
          
      }
      

    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);
          }
          
      }
      

    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);
        }
    }
    
    

智能合约及测试(web3.js)

  • interaction.js智能合约代码封装
    • 创建合约 createFunding
原文地址:https://www.cnblogs.com/xiaocongcong888/p/9553300.html