Category: Ethereum

Practice.sol
L 構造体Clientのclientsという配列に格納して、excesise関数でweightを-2として返却するコントラクトです。

pragma solidity >= 0.4.0 < 0.7.0;

contract Practice {

	struct Client {
		string name;
		string gender;
		uint256 weight;
		uint256 height;
	}
	Client[] public clients;

	function register(string memory _name, string memory _gender, uint256 _weight, uint256 _height) public returns(uint256 id) {
		id = clients.push(Client(_name, _gender, _weight, _height)) - 1;
		return id;
	}

	function excesise() public returns (uint256 newWeight){
		newWeight = clients[0].weight - 2;
		return newWeight;
	}

}

practice_test.js

	describe("practice()", () => {
		it("returns excesized weight", async() => {
			const practice = await PracticeContract.deployed();
			const expected = 63;
			await practice.register("yamada", "male", 65, 175);
			const actual = await practice.excesise.call();
			
			assert.equal(actual, expected, "Weight should be 63");
		})
	})

Contract: Practice
✓ has been deployed successfully
practice()
✓ returns weight (124ms)

2 passing (184ms)

Practice.sol

contract Practice {

	function hello() external pure returns(string memory) {
		return "Hello, World!";
	}

	function tax(uint256 price) public pure returns(uint256 newPrice){
		 newPrice = price * 11 / 10;
		 return newPrice;
	}
}

practice_test.js

	describe("practice()", () => {
		it("returns tax in price", async() => {
			const practice = await PracticeContract.deployed();
			const expected = "110";
			const actual = await practice.tax(100);
			assert.equal(actual, expected, "should be 110");
		})
	})

$ truffle test

Compiling your contracts…
===========================
> Compiling ./contracts/Migrations.sol
> Compiling ./contracts/Practice.sol
> Artifacts written to /tmp/test-202209-108928-12xhvrv.xr0d
> Compiled successfully using:
– solc: 0.5.16+commit.9c3226ce.Emscripten.clang

Contract: Practice
✓ has been deployed successfully
practice()
✓ returns ‘Hello, World!’
practice()
✓ returns tax in price

3 passing (123ms)

taxのmultiplyは　price * 1.1; とするとエラーになるので、price * 11 / 10;としないといけない。
なるほど、中々激しい。

### contractでの宣言

pragma solidity ^0.4.19;

contract ZombieFactory {

    uint dnaDigits = 16;
}

uintは符号なし256ビットinteger(正のみ)、uint8、uint16、 uint32などもある

### 構造体

contract ZombieFactory {

    uint dnaDigits = 16;
    uint dnaModulus = 10 ** dnaDigits;
    
    struct Zombie {
        string name;
        uint dna;
    }

}

### 配列
solidityには固定長配列と可変長配列がある

uint[2] fixedArray;

string[5] stringArray;

uint[] dynamicArray;
```
publicな配列にすれば、他のコントラクトもこの配列を読める
```
contract ZombieFactory {

    uint dnaDigits = 16;
    uint dnaModulus = 10 ** dnaDigits;

    struct Zombie {
        string name;
        uint dna;
    }
    Zonbie[] public zombies;

}

### 関数

function eatHumburgers(string _name, uint _amount) {
	
}

eatHamburgers("vitalink", 100)

実例

    function createZombie(string _name, uint _dna){

    }

### 新しい構造体

Person satoshi = Person(20, "Satoshi");
people.push(satoshi)

people.push(Person(15, "akemi"));

関数の中に書く

    function createZombie(string _name, uint _dna) {
        // ここから始めるのだ
        zombies.push(Zombie(_name, _dna));
    }

### Private/Public
publicの関数は誰でもコントラクトの関数を呼び出して実行できる
以下の様に書くと、contract内の他の関数からのみ読み出せる

uint[] numbers;

function _addToArray(uint _number) private {
	numbers.push(_number);
}

privateの関数はアンダーバー(_)で始めるのが通例

    function _createZombie(string _name, uint _dna) private {
        zombies.push(Zombie(_name, _dna));
    }

### 関数の戻り値

string greeting = "what's up dog";

function sayHello() public returns (string) {
	return greeting;
}

関数で変更するにはviewを使う

function sayHello() public view returns (string) {
	return greeting;
}

テスト

    function _generateRandomDna(string _str) private view returns(uint){
        
    }

### Keccak256
ランダムな256ビットの16進数

    function _generateRandomDna(string _str) private view returns (uint) {
        uint rand = uint(keccak256(_str));
        return rand % dnaModulus;
    }

### 統合

    function createRandomZombie(string _name) public {
        uint randDna = _generateRandomDna(_name);
        _createZombie(_name, randDna);
    }

### event
ブロックチェーンで何かが生じた時にフロントエンドに伝えることができる
何かあったときにアクションを実行する

event IntegersAdded(uint x, uint y, uint result);

function add(uint _x, uint _y) public {
	uint result = _x + _y;
	IntegersAdded(_x, _y, result);
	return result;
}

js側

YourContract.IntegersAdded(function(error, result) {
  // 結果について何らかの処理をする
})

テスト

    event NewZombie(uint zombieId, string name, uint dna);

    function _createZombie(string _name, uint _dna) private {
        uint id = zombies.push(Zombie(_name, _dna)) - 1;
        NewZombie(id, _name, _dna);
    }

### フロントエンド

var abi = ""
var ZombieFactoryContract = web3.eth.contract(abi)
var ZombieFactory = ZombieFactoryContract.at(contractAddress)

#("ourButton").click(function(e) {
	var name = $("#nameInput").val()
	ZombieFactory.createRandomZombie(name)
})

var event = ZombieFactory.NewZombie(function(error, result){
	if(error) return
	generateZombie(result.zombieId, result.name, result.dna)
})

function generateZombie(id, name, dna){
	let dnaStr = String(dna)

	while(dnaStr.length < 16)
		dnaStr = "0" + dnaStr

	let zombieDetails = {
		headChoice: dnaStr.substring(0, 2) % 7 + 1,
	    eyeChoice: dnaStr.substring(2, 4) % 11 + 1,
	    shirtChoice: dnaStr.substring(4, 6) % 6 + 1,
	    skinColorChoice: parseInt(dnaStr.substring(6, 8) / 100 * 360),
	    eyeColorChoice: parseInt(dnaStr.substring(8, 10) / 100 * 360),
	    clothesColorChoice: parseInt(dnaStr.substring(10, 12) / 100 * 360),
	    zombieName: name,
	    zombieDescription: "A Level 1 CryptoZombie",
	}

	return zombieDetails
}

なるほど、ゾンビとかふざけ気味だが、中々のものだな

$ truffle init
$ touch test/practice_test.js

const PracticeContract = artifacts.require("Practice");

contract("Practice", () => {
	it("has been deployed successfully", async() => {
		const practice = await PracticeContract.deployed();
		assert(practice, "contract was not deployed");
	})
})

artifacts.require(“*”) でコンパイル済みのコントラクトを読み込んで操作できる

$ touch contracts/Practice.sol

pragma solidity >= 0.4.0 < 0.7.0;

contract Practice {
	
}

migrationによってcontractがdeployされる
$ touch migrations/2_deploy_practice.js

const PracticeContract = artifacts.require("Practice");

module.exports = function(deployer) {
	deployer.deploy(PracticeContract);
}

contract

pragma solidity >= 0.4.0 < 0.7.0;

contract Practice {

	function hello() external pure returns(string memory) {
		return "Hello, World!";
	}
}

– hello : 関数
– external関数 : practice contactのインターフェイスの一部であり、他のコントラクトから呼び出せるが、コントラクトの中からは呼び出せない。external以外に、internal, public, privateがある。publicは他のコントラクトから呼び出せるし、内部でも呼び出せる。externalをpublicに変更しても結果は同じ。internalとprivateではオブジェクトやthisでは呼び出せない。
– pure, view: コントラクトの変数の状態を変更しない関数　pureはデータを読み込むことも書き込むこともできない　viewは読み込むだけ
– memory : 永続ストレージに配置されているものを一切参照しない

なるほど　分解すると分かりやすい

まず、Minergateに登録する
https://minergate.com/reg

$ sudo apt-get update
$ sudo apt-get install software-properties-common
$ sudo add-apt-repository -y ppa:ethereum/ethereum-qt
$ sudo add-apt-repository ppa:ethereum/ethereum
$ sudo add-apt-repository ppa:ethereum/ethereum-dev
$ sudo apt-get update
$ sudo apt-get install ethminer
$ sudo apt-get install ethminer
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package ethminer
これだと上手くいかない

$ sudo apt install nvidia-cuda-toolkit
$ nvcc -V
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2019 NVIDIA Corporation
Built on Sun_Jul_28_19:07:16_PDT_2019
Cuda compilation tools, release 10.1, V10.1.243

$ mkdir ethminer
$ wget -O ethminer/ethminer.tar.gz https://github.com/ethereum-mining/ethminer/releases/download/v0.18.0/ethminer-0.18.0-cuda-9-linux-x86_64.tar.gz
$ tar xzf ethminer/ethminer.tar.gz -C ethminer/
$ ethminer/bin/ethminer –help
$ ethminer/bin/ethminer -U -P stratum+tcp://eth.pool.minergate.com:45791/*@gmail.com

なるほど　手順はわかった
あとはsolidityの基礎とreact, truffle周りかな

ERC721は、スマートコントラクト内でNon-Fungible Tokenを扱えるようにしたもの

pragma solidity ^0.4.23;

import "github.com/OpenZeppelin/openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol";
import "github.com/OpenZeppelin/openzeppelin-solidity/contracts/token/ERC721/ERC721Mintable.sol";
import "github.com/OpenZeppelin/openzeppelin-solidity/contracts/ownership/Ownable.sol";

contract MyTokenCollection is ERC721Full, ERC721Mintable, Ownable {
	
	constructor() public ERC721Full("MyTokenCollection", "MTC"){}

	function mintTokenCollection(string _tokenURI) public {
		uint256 newTokenId = _getNextTokenId();
		_mint(msg.sender, newTokeId);
		_setTokenURI(newTokenId, _tokenURI);
	}

	function _getNextTokenId() private view returns(uint256){
		return totalSupply().add(1);
	}
}

なるほど、Truffleもう一回ちょっとやり直す必要があるかな
Reactの勉強もしないといけないか…

Ethereum uses ECDSA to generate public-private key pairs as Bitcoin does.
Ethereum address is generated by hashing public key with keccak256, slicing last 20 bytes, and adding “0x” at the top.

privateKey -> derive with ECDSA -> publicKey -> hash -> Ethereum address

const Web3 = require("web3");

const mnemonic = "*";

const HDWalletProvider = require('truffle-hdwallet-provider');
let provider = new HDWalletProvider(mnemonic, 'https://ropsten.infura.io/v3/*', 0, 1);

let web3 = new Web3(provider);

let account = web3.eth.accounts.create();

console.log("address:" + account.address);
console.log("privateKey:" + account.privateKey);

$ node address.js
address:0xefC5B5d9A4BDA3bE4f4da8e7AaFe25F08C5EAce7
privateKey:********
$ node address.js
address:0xB19C2356a88F5437e253d404DA642EC914dCC794
privateKey:********

ニーモニック(mnemonic)はあるだけで口座管理ができる
キーストアはパスワードがないと何も出来ない
MetaMaskのウォレットではmnemonicから秘密鍵を作る仕組みがある

### mnemonic
12ワードは128bitのエントロピーから生成される(randomな値)
エントロピーからチェックサムを生成し足し合わせバイト列に変換し11bit(最大2048)ごとに分割
分割した値をindex値としてワードリストの索引
PBKDF2-SHA512から生成 2048回ストレッチ

なるほど、中々凄いことになってるわ

sample_greeting.sol

contract SampleGreeting {
	string greeting = 'Hello World';

	function getGreet() public view returns (string memory){
		return greeting;
	}
}

$ sudo snap install solc
$ solc –bin –abi sample_greeting.sol
sample_greeting.sol:1:1: Warning: Source file does not specify required compiler version! Consider adding “pragma solidity ^0.5.16;”
contract SampleGreeting {
^ (Relevant source part starts here and spans across multiple lines).

======= sample_greeting.sol:SampleGreeting =======
Binary:
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
Contract JSON ABI
[{“constant”:true,”inputs”:[],”name”:”getGreet”,”outputs”:[{“internalType”:”string”,”name”:””,”type”:”string”}],”payable”:false,”stateMutability”:”view”,”type”:”function”}]

const Web3 = require('web3');

const mnemonic = "*";

const HDWalletProvider = require('truffle-hdwallet-provider');
let provider = new HDWalletProvider(mnemonic, 'https://ropsten.infura.io/v3/*', 0, 1);

let web3 = new Web3(provider);

let bin = '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';
let abi = [{"constant":true,"inputs":[],"name":"getGreet","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"}];
let data = {
	'data': bin
}

let contract = new web3.eth.Contract(abi, null, data);
console.log('contract:', contract);

$ node sample.js
///
_jsonInterface:
[ { constant: true,
inputs: [],
name: ‘getGreet’,
outputs: [Array],
payable: false,
stateMutability: ‘view’,
type: ‘function’,
signature: ‘*’ } ] }

signatureの値をメモしておく

web3.eth.getGasPrice().
	then((averageGasPrice) => {
		console.log("gasPrice: " + averageGasPrice);
	}).catch(console.error);

web3.eth.getAccounts((error, result) => {
	console.log('result: ', result);

	web3.eth.getTransactionCount(result[0], (error, response)=>{
		console.log('nonce:', response);
	})
})

contract.deploy().estimateGas().
	then((estimatedGas) => {
		console.log("gas: " + estimatedGas);
	}).catch(console.error);

$ node sample.js
result: [ ‘*’ ]
gasPrice: 1500000013
gas: 164431
nonce: 3

let sender_address = "*";
let nonce = '3';
let chainId = '3';
let gas = 164431;
let gasPrice = '1500000013'

let tx = {
  'from': sender_address,
  'nonce': nonce,
  'chainId': chainId,
  'gas': gas,
  'gasPrice': gasPrice,
  'data': bin,
}

const PRIVATE_KEY = "*";

web3.eth.accounts.signTransaction(tx, PRIVATE_KEY, (error, response)=>{
    console.log(response);
});

{ messageHash:
‘0x71d7*’,
v: ‘0x2a’,
r:
‘0xd04f9c44192de22c1088feccc*’,
s:
‘0x593a5ec5a50d1d5bed367*’,
rawTransaction:
‘0xf902f2038459682f0d8302824f8080b902a060806040526040518060400160405280600b81526020017f48656c6c6f20576f726c640000000000000000000000000000000000000000008152506000908051906020019061004f929190610062565b5034801561005c57600080fd5b50610107565b828054600181600116156101000203166002900490600052602060002090601f016020900481019282601f106100a357805160ff19168380011785556100d1565b828001600101855582156100d1579182015b828111156100d05782518255916020019190600101906100b5565b5b5090506100de91906100e2565b5090565b61010491905b808211156101005760008160009055506001016100e8565b5090565b90565b61018a806101166000396000f3fe608060405234801561001057600080fd5b506004361061002b5760003560e01c8063d705a4b514610030575b600080fd5b6100386100b3565b604051808060200182810*’,
transactionHash:
‘0x55a06ab424128b04b9002fe7de1a17e8981d94728bac06dd55993cfdba1b860d’ }

デプロイ

let raw = '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*';

web3.eth.sendSignedTransaction(raw).on('receipt', console.log);

$ node sample.js
{ blockHash:
‘0x8414d2fac3b36315828b7d330287a181e3b58ac29ee5d1325fb27b6d92dc03d1’,
blockNumber: 11682111,
contractAddress: ‘0x31695391C6C0f3A3F2EDe7cDb9B13Da277A8e2Eb’,
cumulativeGasUsed: 1680291,
effectiveGasPrice: ‘0x59682f0d’,
from: ‘0x71c9f1d5be00173ae7b774bdbe2112cdd03c5c92’,
gasUsed: 164431,
logs: [],
logsBloom:
‘0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000’,
status: true,
to: null,
transactionHash:
‘0x55a06ab424128b04b9002fe7de1a17e8981d94728bac06dd55993cfdba1b860d’,
transactionIndex: 13,
type: ‘0x0’ }

web3.eth.getAccounts((error, result)=> {
	let sender_address = result[0]
	let call_data = {
		'from': sender_address,
		'to': recipient_address,
		'data': signature
	}

	web3.eth.call(call_data, (error, response) => {
		console.log('response: ', response);
		provider.engine.stop();
	})
})

$ node sample.js
response: 0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000b48656c6c6f20576f726c64000000000000000000000000000000000000000000

おおおお なるほど
solidityでcompileしたデータを、from, nonce, chainId, gas, gasPriceなどと一緒にトランザクションにして秘密鍵で署名してデプロイしてるのね。

一連の流れはわかった!

$ mkdir rinkeby
$ cd rinkeby
$ npm init

{
  "name": "inbox",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC"
}

solidityのcompilerをinstall
$ npm install –save solc

mocha(テストフレーム)をinstall
$ npm install –save mocha ganache-cli web3@1.0.0-beta.26

truffle-hdwallet-providerをインストール
$ npm install –save truffle-hdwallet-provider@0.0.3

const path = require('path');
const fs = require('fs');
const solc = require('solc');

const inboxPath = path.resolve(__dirname, 'contracts', 'Inbox.sol');
const source = fs.readFileSync(inboxPath, 'utf8');

moudle.exports = solc.compile(source,1).contracts[':Inbox'];

Inbox.sol

pragma solidity ^0.8.11;

contract Inbox {
	string public message;

	function Inbox(string initialMessage) public {
		message = initialMessage;
	}

	function setMessage(string newMessage) public {
		message = newMessage;
	}
}

deploy.js

const HDWalletProvider = require('truffle-hdwallet-provider');
const Web3 = require('web3');
const { interface, bytecode } = require('./compile');

const provider = new HDWalletProvider (
	'harmonic',
	'https://ropsten.infura.io/v3/*'
);

const web3 = new Web3(provider);

const deploy = async () => {

	const accounts = await web3.eth.getAccounts();

	console.log('Attempting to deploy from account', accounts[0]);

	const result = await new web3.eth.Contract(JSON.parse(interface))
		.deploy({data: bytecode, arguments:['Hi there!']})
		.send({gas:'1000000', from: accounts:[0]});

	console.log('Contract deploy to', result.options.address);
}

$ node deploy.js
Attempting to deploy from account *
(node:408216) UnhandledPromiseRejectionWarning: Error: intrinsic gas too low

うーむ、gasの設定の方法がよくわかん
gasの概念の理解が先か…