在以太坊發行代幣Token系列教程(1)
雖然國家目前嚴令禁止ICO,但是我覺得基於區塊鏈平臺的虛擬幣本身是很有價值的,大家只要不去碰基於發幣的ICO就好,因此這裡簡單談談怎麼在以太坊發行自己的代幣(Test網路)。
翻牆
目前來說,相關的網站很多都是被牆的,因此沒有梯子建議就放棄吧,推薦自己購買香港或者海外的雲伺服器,用shadowsocks搭建代理,注意如果用阿里雲的話,不要用視訊等大流量服務,可能會被封。
下載安裝
下載並安裝最新版本以太坊錢包
選擇網路
下載好以太坊錢包後選擇testnet
,別選成mainnet
了,建立代幣合約和轉賬代幣是要收費的。選好testnet後,錢包會去同步區塊資訊,目前都是快速同步區塊的header,而且是點對點的方式,所以很快。
建立賬戶
在錢包介面選擇Wallet,然後選擇ADD ACCOUNT
領取測試環境的以太幣ether
新建完賬戶,餘額是0.00ether
因此我們需要領取一些rinkeby測試環境的ether,進入連結,可以看到有三種方法獲取,我們就用第一種發推特的方式,點選下面圈出來的tweet的連結:
接著會彈出以下推文,把0x0000…換成你的賬戶地址0x…,然後釋出推文即可:
接著進入twitter,找到發表的推文,拷貝連結:
最後回到領取ether的連結,把推文連結貼上進去
過大概3-10分鐘,就能在你的錢包看到ether幣了!
建立智慧合約
拷貝以下合約程式碼(這段程式碼是從官方的token例子
pragma solidity ^0.4.16;
interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external; }
contract TokenERC20 {
// Public variables of the token
string public name;
string public symbol;
uint8 public decimals = 18;
// 18 decimals is the strongly suggested default, avoid changing it
uint256 public totalSupply;
// This creates an array with all balances
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;
// This generates a public event on the blockchain that will notify clients
event Transfer(address indexed from, address indexed to, uint256 value);
// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);
/**
* Constructor function
*
* Initializes contract with initial supply tokens to the creator of the contract
*/
function TokenERC20(
uint256 initialSupply,
string tokenName,
string tokenSymbol
) public {
totalSupply = initialSupply * 10 ** uint256(decimals); // Update total supply with the decimal amount
balanceOf[msg.sender] = totalSupply; // Give the creator all initial tokens
name = tokenName; // Set the name for display purposes
symbol = tokenSymbol; // Set the symbol for display purposes
}
/**
* Internal transfer, only can be called by this contract
*/
function _transfer(address _from, address _to, uint _value) internal {
// Prevent transfer to 0x0 address. Use burn() instead
require(_to != 0x0);
// Check if the sender has enough
require(balanceOf[_from] >= _value);
// Check for overflows
require(balanceOf[_to] + _value > balanceOf[_to]);
// Save this for an assertion in the future
uint previousBalances = balanceOf[_from] + balanceOf[_to];
// Subtract from the sender
balanceOf[_from] -= _value;
// Add the same to the recipient
balanceOf[_to] += _value;
emit Transfer(_from, _to, _value);
// Asserts are used to use static analysis to find bugs in your code. They should never fail
assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
}
/**
* Transfer tokens
*
* Send `_value` tokens to `_to` from your account
*
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transfer(address _to, uint256 _value) public {
_transfer(msg.sender, _to, _value);
}
/**
* Transfer tokens from other address
*
* Send `_value` tokens to `_to` on behalf of `_from`
*
* @param _from The address of the sender
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
require(_value <= allowance[_from][msg.sender]); // Check allowance
allowance[_from][msg.sender] -= _value;
_transfer(_from, _to, _value);
return true;
}
/**
* Set allowance for other address
*
* Allows `_spender` to spend no more than `_value` tokens on your behalf
*
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
*/
function approve(address _spender, uint256 _value) public
returns (bool success) {
allowance[msg.sender][_spender] = _value;
return true;
}
/**
* Set allowance for other address and notify
*
* Allows `_spender` to spend no more than `_value` tokens on your behalf, and then ping the contract about it
*
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
* @param _extraData some extra information to send to the approved contract
*/
function approveAndCall(address _spender, uint256 _value, bytes _extraData)
public
returns (bool success) {
tokenRecipient spender = tokenRecipient(_spender);
if (approve(_spender, _value)) {
spender.receiveApproval(msg.sender, _value, this, _extraData);
return true;
}
}
/**
* Destroy tokens
*
* Remove `_value` tokens from the system irreversibly
*
* @param _value the amount of money to burn
*/
function burn(uint256 _value) public returns (bool success) {
require(balanceOf[msg.sender] >= _value); // Check if the sender has enough
balanceOf[msg.sender] -= _value; // Subtract from the sender
totalSupply -= _value; // Updates totalSupply
emit Burn(msg.sender, _value);
return true;
}
/**
* Destroy tokens from other account
*
* Remove `_value` tokens from the system irreversibly on behalf of `_from`.
*
* @param _from the address of the sender
* @param _value the amount of money to burn
*/
function burnFrom(address _from, uint256 _value) public returns (bool success) {
require(balanceOf[_from] >= _value); // Check if the targeted balance is enough
require(_value <= allowance[_from][msg.sender]); // Check allowance
balanceOf[_from] -= _value; // Subtract from the targeted balance
allowance[_from][msg.sender] -= _value; // Subtract from the sender's allowance
totalSupply -= _value; // Update totalSupply
emit Burn(_from, _value);
return true;
}
}
token name ,和 token symbol自己可以隨便命名,然後把費用Fee拉到最大(Faster,為了更快的讓礦工記錄你的合約),最後點擊發布就ok了。
發起轉賬
目標賬戶地址可以填寫[0x8DF451466Ee0e75F73eafB36a8C0833F3022a687](/send/0x8DF451466Ee0e75F73eafB36a8C0833F3022a687 "0x8DF451466Ee0e75F73eafB36a8C0833F3022a687")
檢視轉賬資訊
點選其中一筆轉賬
點選上圖的Transaction下的藍色地址,可以前往rinkeby.io檢視詳細資訊
小結
發代幣的基本方法已經介紹完了,在後續章節,會繼續介紹發行代幣的高階技巧,歡迎大家訂閱。
這裡要額外提一下,發代幣的關鍵就是智慧合約,而智慧合約一旦上傳是不可變的,因此請務必小心謹慎:
- 確保智慧合約沒有Bug,一旦存在Bug,你就別想去修復了
- 程式碼要儘量簡潔,程式碼越長,執行費用越高(每次轉賬都要執行一次)
同時,大家也可以在這裡檢視代幣的Coin