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以太坊手把手空氣幣發幣教學 - 割韭菜起手式

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超簡單以太坊空氣幣發幣教學 (自己的幣自己發)

幣圈一天,人間一年。在 ICO 的世界裡,笑稱「不管黑幣白幣,能忽悠的就是好幣」。雖然現在已經開始瘋 STO 了,過時的我最近剛好研究了一下 Ethereum 智能合約,今天過氣的教教大家如何在以太坊發弊 ICO

為了跟上時代潮流的尾巴,今天教大家如何自己發行 ETH ERC-20 標準的 Token 代幣。所有教學動作可透過 Chrome 瀏覽器 + MetaMask 錢包即可完成,今年要好野就看這一篇了。

什麼是 ERC-20 標準代幣?

ERC-20 是基於以太坊 (Ethereum) 上發行智能合約的一種標準,智能合約是一段可以在區塊鏈執行的程式碼,這個 ERC-20 標準就是程式裡頭常常使用的 Interface 概念。ERC-20 Interface 定義如下:

contract ERC20Interface {
    function totalSupply() public view returns (uint);
    function balanceOf(address tokenOwner) public view returns (uint balance);
    function allowance(address tokenOwner, address spender) public view returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);
 
    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

如果你的智能合約實做了上述的介面,那就可以符合 ERC-20 的規範 (ERC-20官方規範在這裡),大家就知道如何使用你的代幣,讓代幣的流通更方便了。話說現在有 14 萬以上種類的 ERC-20 Token 被發行,我是不相信啦(不相信那麼少,寫這篇文章的時候我就發了 3 種幣了),難道真的大家都有兩億!

此外,ERC-20 有一些弊端,比如將 Token 轉帳 (transfer) 到一個智能合約的時候,由於邏輯的關係有可能造成卡死,你的 Token 就進到黑洞了。因此後來延伸 ERC-20 出現了 ERC-223 標準,透過 tokenFallback 函式進行驗證,避免代幣被錯誤使用造成代幣消失的問題。但目前官方 theethereum Wiki 還沒有出現這個標準的相關定義,我們今年還是以 ERC-20 來實做發幣。

於以太坊測試公網進行智能合約發布測試

首先,我們準備好錢包與領取測試用的 ETH。啟動你的 Chrome 先安裝 MetaMask Extension,安裝好後請先註冊一個錢包,接著切換為測試網路,如下圖:

一開始切換到測試網路,會沒有任何 ETH 可以使用,但是佈署與執行智能合約需要 ETH,你可以從以下連結免費領取一個 ETH 來測試使用:

https://faucet.ropsten.be/

填上你的錢包位置:

然後等一下看看你的 MetaMask 應該就有 1 ETH 可以揮霍了,記住這是測試公網,可別天真的以為可以轉去交易所買賣啊~好的開始是成功的全部,做到這裡已經快要可以割韭菜了~

開始製作 ERC-20 代幣智能合約

再來我們要在測試網路佈署這個空氣幣的智能合約,以太坊智能合約使用 Solidity 語言撰寫,所以我們先來學一下 Solidity 語言.......(誤~我不會啊~)

這裡我們會用到一個叫做 Remix 的以太坊 Web 線上智能合約編譯佈署工具,先連到 https://remix.ethereum.org 然後按下「+」圖示新增一個 .sol 檔案,如下:

然後輸入一個酷炫的檔名如下:

然後貼上官方提供的範例,修改後已經同步放在 GitHub ERC-20.sol 檔案,內容如下:

pragma solidity ^0.5.0;

// ----------------------------------------------------------------------------
// Safe maths
// ----------------------------------------------------------------------------
library SafeMath {
    function add(uint a, uint b) internal pure returns (uint c) {
        c = a + b;
        require(c >= a);
    }
    function sub(uint a, uint b) internal pure returns (uint c) {
        require(b <= a);
        c = a - b;
    }
    function mul(uint a, uint b) internal pure returns (uint c) {
        c = a * b;
        require(a == 0 || c / a == b);
    }
    function div(uint a, uint b) internal pure returns (uint c) {
        require(b > 0);
        c = a / b;
    }
}


// ----------------------------------------------------------------------------
// ERC Token Standard #20 Interface
// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
// ----------------------------------------------------------------------------
contract ERC20Interface {
    function totalSupply() public view returns (uint);
    function balanceOf(address tokenOwner) public view returns (uint balance);
    function allowance(address tokenOwner, address spender) public view returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);

    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}


// ----------------------------------------------------------------------------
// Contract function to receive approval and execute function in one call
//
// Borrowed from MiniMeToken
// ----------------------------------------------------------------------------
contract ApproveAndCallFallBack {
    function receiveApproval(address from, uint256 tokens, address token, bytes memory data) public;
}


// ----------------------------------------------------------------------------
// Owned contract
// ----------------------------------------------------------------------------
contract Owned {
    address public owner;
    address public newOwner;

    event OwnershipTransferred(address indexed _from, address indexed _to);

    constructor() public {
        owner = msg.sender;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address _newOwner) public onlyOwner {
        newOwner = _newOwner;
    }
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}


// ----------------------------------------------------------------------------
// ERC20 Token, with the addition of symbol, name and decimals and a
// fixed supply
// ----------------------------------------------------------------------------
contract AirToken is ERC20Interface, Owned {
    using SafeMath for uint;

    string public symbol;
    string public  name;
    uint8 public decimals;
    uint _totalSupply;

    mapping(address => uint) balances;
    mapping(address => mapping(address => uint)) allowed;


    // ------------------------------------------------------------------------
    // Constructor
    // ------------------------------------------------------------------------
    constructor() public {
        symbol = "AirCoin";
        name = "空氣幣";
        decimals = 3;
        _totalSupply = 200000000 * 10**uint(decimals);
        balances[0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFF] = _totalSupply;
        emit Transfer(address(0), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, _totalSupply);
    }


    // ------------------------------------------------------------------------
    // Total supply
    // ------------------------------------------------------------------------
    function totalSupply() public view returns (uint) {
        return _totalSupply.sub(balances[address(0)]);
    }


    // ------------------------------------------------------------------------
    // Get the token balance for account `tokenOwner`
    // ------------------------------------------------------------------------
    function balanceOf(address tokenOwner) public view returns (uint balance) {
        return balances[tokenOwner];
    }


    // ------------------------------------------------------------------------
    // Transfer the balance from token owner's account to `to` account
    // - Owner's account must have sufficient balance to transfer
    // - 0 value transfers are allowed
    // ------------------------------------------------------------------------
    function transfer(address to, uint tokens) public returns (bool success) {
        balances[msg.sender] = balances[msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        emit Transfer(msg.sender, to, tokens);
        return true;
    }


    // ------------------------------------------------------------------------
    // Token owner can approve for `spender` to transferFrom(...) `tokens`
    // from the token owner's account
    //
    // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
    // recommends that there are no checks for the approval double-spend attack
    // as this should be implemented in user interfaces
    // ------------------------------------------------------------------------
    function approve(address spender, uint tokens) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        return true;
    }


    // ------------------------------------------------------------------------
    // Transfer `tokens` from the `from` account to the `to` account
    //
    // The calling account must already have sufficient tokens approve(...)-d
    // for spending from the `from` account and
    // - From account must have sufficient balance to transfer
    // - Spender must have sufficient allowance to transfer
    // - 0 value transfers are allowed
    // ------------------------------------------------------------------------
    function transferFrom(address from, address to, uint tokens) public returns (bool success) {
        balances[from] = balances[from].sub(tokens);
        allowed[from][msg.sender] = allowed[from][msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        emit Transfer(from, to, tokens);
        return true;
    }


    // ------------------------------------------------------------------------
    // Returns the amount of tokens approved by the owner that can be
    // transferred to the spender's account
    // ------------------------------------------------------------------------
    function allowance(address tokenOwner, address spender) public view returns (uint remaining) {
        return allowed[tokenOwner][spender];
    }


    // ------------------------------------------------------------------------
    // Token owner can approve for `spender` to transferFrom(...) `tokens`
    // from the token owner's account. The `spender` contract function
    // `receiveApproval(...)` is then executed
    // ------------------------------------------------------------------------
    function approveAndCall(address spender, uint tokens, bytes memory data) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, address(this), data);
        return true;
    }


    // ------------------------------------------------------------------------
    // Don't accept ETH
    // ------------------------------------------------------------------------
    function () external payable {
        revert();
    }


    // ------------------------------------------------------------------------
    // Owner can transfer out any accidentally sent ERC20 tokens
    // ------------------------------------------------------------------------
    function transferAnyERC20Token(address tokenAddress, uint tokens) public onlyOwner returns (bool success) {
        return ERC20Interface(tokenAddress).transfer(owner, tokens);
    }
}

上述合約需要更改的地方很少,只有以下幾點:

    constructor() public {
        symbol = "AirCoin";
        name = "空氣幣";
        decimals = 3;
        _totalSupply = 200000000 * 10**uint(decimals);
        balances[0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFF] = _totalSupply;
        emit Transfer(address(0), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, _totalSupply);
    }

貼上後按下「Start to compile (Ctrl-S)」按鈕進行編譯,編譯成功畫面如下:

再來切換到 Run 功能,選擇我們要佈署的合約設定如下圖:

按下「Deploy」這時你的 MetaMask 回出現確認畫面,按下「CONFIRM」進行佈署,如下:

讓子彈飛一下,我們可以看到交易為 Pending 狀態,需要先等待區塊鏈處理交易,如下:

好囉,點選詳細資料,看一下 Etherscan 的狀態如下:

交易很順利被包進 Block,接著我們看看帳戶是不是有 Token 了,先複製 Remix 智能合約的 Address,如下:

然後到 MetaMask 點選「選單」底下有一個「ADD TOKEN」,進入後選擇「Custom Token」並填上我們剛剛的合約位置,如下:

按下「NEXT」畫面會自動帶出餘額數量,然後按下「ADD TOKENS」確認新增:

然後在 MetaMask 主畫面就可以看到 2E 空氣幣進帳囉:

Ethereum 發幣之後

接下來呢?是不是要開始忽悠這個 AirCoin 的價值呢?要 ICO 嗎?別鬧了,這是以太坊測試網路,而且想要 ICO 請必須滿足三大條件:

三缺三我看我還是先洗洗睡吧~

為了證明我發幣的決心,我決定下重本 (大概 0.5 鎂) 在以太坊公鏈發行 AirCoin 代幣 (正式官方名稱為空氣幣),一共發行 2 億個 Token (本來要發 10E 但是我改 Code 忘記重新 Compile……. XD),至於 AirCoin 的用途、願景與理想我現在還沒想到,可能還需要點時間。以太坊公網全球限量保證不增發的 AirToken 合約如下:

0x5eb53a54f5f15f03dd98c63ec4cf28b9ef7747d6

另外如果有人想要這個未來可能會爆漲的 AirCoin 空氣幣 (ETH 正式公網喔),請與我聯繫,如果我還有 Gas 就會發囉,現正免費灑幣中!

其他有想到再補充了,今天先介紹到這裡.......啊掰~

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