web3.js@0.2x.x web3.eth.contract

web3.eth.contract(abiArray)

Solidity コントラクトのためのコントラクトオブジェクトを作成します。

パラメータ

コントラクトのイベント及び関数を伴うABI 配列

戻り値

コントラクトオブジェクトの使用方法

code:web3.eth.contract.js

var MyContract = web3.eth.contract(abiArray);

// instantiate by address

var contractInstance = MyContract.at(address);

// deploy new contract

// Get the data to deploy the contract manually

// contractData = '0x12345643213456000000000023434234'

任意のアドレスを指定してすでに存在するコントラクトを呼び出したり、コンパイル済みのバイトコードを使用してコントラクトをデプロイすることができます。

code:web3.eth.contract.js

// Instantiate from an existing address:

var myContractInstance = MyContract.at(myContractAddress);

// Or deploy a new contract:

// Deploy the contract asynchronous from Solidity file:

...

const fs = require("fs");

const solc = require('solc')

let source = fs.readFileSync('nameContract.sol', 'utf8');

let compiledContract = solc.compile(source, 1);

let gasEstimate = web3.eth.estimateGas({data: bytecode});

let MyContract = web3.eth.contract(JSON.parse(abi));

var myContractReturned = MyContract.new(param1, param2, {

from:mySenderAddress,

data:bytecode,

gas:gasEstimate}, function(err, myContract){

if(!err) {

// NOTE: The callback will fire twice!

// Once the contract has the transactionHash property set and once its deployed on an address.

// e.g. check tx hash on the first call (transaction send)

if(!myContract.address) {

console.log(myContract.transactionHash) // The hash of the transaction, which deploys the contract

// check address on the second call (contract deployed)

} else {

console.log(myContract.address) // the contract address

}

// Note that the returned "myContractReturned" === "myContract",

// so the returned "myContractReturned" object will also get the address set.

}

});

// Deploy contract syncronous: The address will be added as soon as the contract is mined.

// Additionally you can watch the transaction by using the "transactionHash" property

var myContractInstance = MyContract.new(param1, param2, {data: myContractCode, gas: 300000, from: mySenderAddress});

myContractInstance.transactionHash // The hash of the transaction, which created the contract

myContractInstance.address // undefined at start, but will be auto-filled later

上記の使用方法の部分を日本語でわかりやすく説明したい

サンプルコード

code:example.js

// contract abi

var abi = [{

name: 'myConstantMethod',

type: 'function',

constant: true,

}, {

name: 'myStateChangingMethod',

type: 'function',

constant: false,

outputs: []

}, {

name: 'myEvent',

type: 'event',

}];

// creation of contract object

var MyContract = web3.eth.contract(abi);

// initiate contract for an address

var myContractInstance = MyContract.at('0xc4abd0339eb8d57087278718986382264244252f');

// call constant function

var result = myContractInstance.myConstantMethod('myParam');

console.log(result) // '0x25434534534'

// send a transaction to a function

myContractInstance.myStateChangingMethod('someParam1', 23, {value: 200, gas: 2000});

// short hand style

web3.eth.contract(abi).at(address).myAwesomeMethod(...);

// create filter

var filter = myContractInstance.myEvent({a: 5}, function (error, result) {

if (!error)

console.log(result);

/*

{

address: '0x8718986382264244252fc4abd0339eb8d5708727',

topics: "0x12345678901234567890123456789012", "0x0000000000000000000000000000000000000000000000000000000000000005",

data: "0x0000000000000000000000000000000000000000000000000000000000000001",

...

}

*/

});

参考