Guidelines for Taifang Block Chain Development from Zero

Preface

In the last article, we introduced Geth installation, and today we describe how to deploy smart contracts.If you haven't read the last introductory article yet, I suggest you read the last one first Guidelines for Taifang Block Chain Development from Zero .Deploying smart contracts first requires a contract file written by solidity and a framework for developing Ethernet Truffle

Install Solc
solc is the compiler used to compile smart contract files.

npm install -g solc

Check if the installation is successful after the installation is complete.

$solcjs --version
0.4.19+commit.c4cbbb05.Emscripten.clang

The output version number indicates that the installation was successful.

Install Truffle

npm install -g truffle

After installing Truffle, we run the command.

truffle version

output

Truffle v4.0.3 (core: 4.0.3)
Solidity v0.4.18 (solc-js)

Indicates that we have successfully installed Truffle.

Create solidity project

We select a directory to create a solidity project that runs under

truffle init

Create solidity project

This command automatically creates a project and associated files.And created a contract file for us, Migrations.sol

Project directory created by truffle

Create vote.sol
Add the Voting.sol file to the contracts folder created by truffle init above. This is a voting application. As long as you have programming experience, I believe the solidity syntax is not difficult for you. copy in the solidity code below

pragma solidity ^0.4.2;

contract Voting{
    //voter struct
    struct Voter{
        bytes32 name;
        bool voted;//is voted or not
        uint vote;//vote who
        uint givenRightTime;//aurth  time
        uint votetime;//vote time
    }
    struct Proposal{
        bytes32 name;
        uint voteCount;
    }
    address public chairperson;//vote initiator
    
    mapping(address=>Voter)public voters;//voters
    Proposal[] public proposals;//can vote to who
    
    //constructor
    function  Voting(bytes32[] proposalNames) public{
        chairperson = msg.sender;
        //init proposals
        for(uint i = 0;i<proposalNames.length;i++){
            proposals.push(Proposal({name:proposalNames[i],voteCount:0}));
        }
    }
    
    function giveRightToVote(address voter,bytes32 voterName) public{
        if(msg.sender != chairperson || voters[voter].voted){
            revert();
        }
        voters[voter].name = voterName;
        voters[voter].voted = false;
        voters[voter].votetime = 0 ;
        voters[voter].givenRightTime = now;
    }
    
    //vote
    function vote(uint proposalIndex)public{
        Voter storage sender = voters[msg.sender];
        //check is voted
        if(sender.voted){
            revert();
        }
        //modify sender status
        sender.voted = true ;
        sender.votetime = now;
        sender.vote =  proposalIndex;
        proposals[proposalIndex].voteCount += 1;
    }
    
    //get winner
    function winningProposalIndex()public constant returns(uint winningProposalIndex){
        uint winningVoteCount = 0;
        for(uint p = 0 ;p<proposals.length;p++){
            if(proposals[p].voteCount > winningVoteCount){
                winningVoteCount = proposals[p].voteCount;
                winningProposalIndex = p ;
            }
        }
    }
    
    function winnerName()public constant returns(bytes32 winnerName){
        winnerName = proposals[winningProposalIndex()].name;
    }
}

Compile contracts using Truffle
Open truffle.js inside the project and copy in the following configuration.

module.exports = {
  // See <http://truffleframework.com/docs/advanced/configuration>
  // to customize your Truffle configuration!
  networks: {
    development: {
      host: "localhost",
      port: 8081,
      network_id: "*", // Match any network id
      gas: 1000000
    }
  }
};

host and port are the IP addresses and ports of one of your local Ethernet nodes, gas is the coin for deployment, and then open 1_initial_migration.js under the migrations folder of the project file to change the file you want to deploy to Voting.sol.

// var Migrations = artifacts.require("./Migrations.sol");
var Voting = artifacts.require("./Voting.sol");
module.exports = function(deployer) {
  deployer.deploy(Voting,['hexo','tfboys']);
};