Greeter Contract 만들기

Greeter.sol

contract Mortal {
    /* Define variable owner of the type address */
    address owner;

    /* This function is executed at initialization and sets the owner of the contract */
    function Mortal() { owner = msg.sender; }

    /* Function to recover the funds on the contract */
    function kill() { if (msg.sender == owner) selfdestruct(owner); }
}

contract Greeter is Mortal {
    /* Define variable greeting of the type string */
    string greeting;

    /* This runs when the contract is executed */
    function Greeter(string _greeting) public {
        greeting = _greeting;
    }

    /* Main function */
    function greet() constant returns (string) {
        return greeting;
    }
}

solidity compiler 설치 및 컴파일 하기

solcjs 설치하기

npm install -g solc

컴파일 하기

solcjs -o target --bin --abi Greeter.sol

js 스크립트 작성

main.js

var greeterFactory = eth.contract(<contents of the file Greeter.abi>)

var greeterCompiled = "0x" + "<contents of the file Greeter.bin>"

var _greeting = "Hello World!"

var greeter = greeterFactory.new(_greeting,{from:eth.accounts[0],data:greeterCompiled,gas:47000000}, function(e, contract){
    if(e) {
      console.error(e); // If something goes wrong, at least we'll know.
      return;
    }

    if(!contract.address) {
      console.log("Contract transaction send: TransactionHash: " + contract.transactionHash + " waiting to be mined...");

    } else {
      console.log("Contract mined! Address: " + contract.address);
      console.log(contract);
    }
})

geth console 에서 스크립트 실행

loadScript("main.js")

채굴 시작 및 greeter 실행

miner.start()

채굴이 완료되면 contract에 address가 부여되고 계약이 발행된다.

이제는 블록체인 상에 greeter라는 봇이 생성되었으므로 다음과 같이 자유롭게 호출하여 사용이 가능하다.

greeter.greet();