最近做個一些區塊鍊外包相關的項目,現在總結下以太坊代币發行,以及區塊連結入的過程。有興趣可以去看看,摩爾支付。
背景是基于django rest framwork, 就是python 啦. 前台就是vue與angularjs.
下面主要總結下區塊鍊相關的開發工作。
首先要接入以太坊,使用geth用戶端, 作業系統centos7.
安裝完畢後同步區塊,最初用的是虛拟機,結果eth測試網就同步了兩周。後來換了一台高性能PC,1天就同步完成了。
區塊同步完成後,eth.syncing 顯示為false. 這時可以用一些基本的指令與以太坊網絡進行互動。
因為背景用的是PYTHON,是以基于python web3是首選。版本要求3.6以上. 不得不更新python.
測試網絡無論是轉ETH或代币都很快,速度在10秒以内。
以太坊發币比較簡單,貼下合約代碼.
interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public; }
contract Ownable {
address public owner;
function Ownable(){
owner = msg.sender;
}
modifier onlyOwner () {
require(msg.sender == owner);
_;
}
}
contract TokenERC20 is Ownable{
string public name;
string public symbol;
uint8 public decimals = 2; // 18 是建議的預設值
uint256 public totalSupply;
mapping (address => uint256) public balanceOf; //
mapping (address => mapping (address => uint256)) public allowance;
event Transfer(address indexed from, address indexed to, uint256 value);
event Mint(address indexed to, uint256 amount);
event Burn(address indexed from, uint256 value);
function transferOwnership(address newOwner) onlyOwner public{
require(newOwner != address(0));
owner = newOwner;
}
function TokenERC20(uint256 initialSupply, string tokenName, string tokenSymbol) public {
totalSupply = initialSupply * 10 ** uint256(decimals);
balanceOf[msg.sender] = totalSupply;
name = tokenName;
symbol = tokenSymbol;
}
function mint(address _to, uint256 _amount) onlyOwner public returns (bool){
totalSupply += _amount * 10 ** uint256(decimals);
balanceOf[_to] += _amount * 10 ** uint256(decimals);
Mint(_to, _amount);
return true;
}
function _transfer(address _from, address _to, uint _value) internal {
require(_to != 0x0);
require(balanceOf[_from] >= _value);
require(balanceOf[_to] + _value > balanceOf[_to]);
uint previousBalances = balanceOf[_from] + balanceOf[_to];
balanceOf[_from] -= _value;
balanceOf[_to] += _value;
Transfer(_from, _to, _value);
assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
}
function transfer(address _to, uint256 _value) public {
_transfer(msg.sender, _to, _value);
}
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;
}
function approve(address _spender, uint256 _value) public
returns (bool success) {
allowance[msg.sender][_spender] = _value;
return true;
}
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;
}
}
function burn(uint256 _value) public returns (bool success) {
require(balanceOf[msg.sender] >= _value);
balanceOf[msg.sender] -= _value;
totalSupply -= _value;
Burn(msg.sender, _value);
return true;
}
function burnFrom(address _from, uint256 _value) public returns (bool success) {
require(balanceOf[_from] >= _value);
require(_value <= allowance[_from][msg.sender]);
balanceOf[_from] -= _value;
allowance[_from][msg.sender] -= _value;
totalSupply -= _value;
Burn(_from, _value);
return true;
}
}
這個是标準ERC20代币,建立合約時指定發行貨币數量,并提供轉賬,銷毀等标準接口。
這裡預留了一個增發代币的接口。隻有owner可以增發。
合約的開發與調試可以在 remix 中完成。
合約調用可以使用python web3。貼一下關鍵的代碼。
web3 = Web3(HTTPProvider(ETH_SERVER))
contract = web3.eth.contract(abi=MOL_ABI, address=Web3.toChecksumAddress(ETH_MOL_ADDRESS))
muser = MUser.objects.get(user_id=userid)
ret = web3.personal.unlockAccount(Web3.toChecksumAddress(muser.eth), muser.eth_pass, 60)
if ret:
param = []
param.append(str(dst_address))
param.append(int(float(amount) * 100))
res = contract.transact({'from': Web3.toChecksumAddress(muser.eth), 'gas': 90000}).transfer(Web3.toChecksumAddress(param[0]), param[1])
# tx_hash = to_hex(res)
# return tx_hash
# print(web3.toText(res))
else:
print("trans mol failed")
步驟就是 1,初始化合約 2,解鎖以太坊位址 3,通過合約轉移代币。
這樣就可以控制合約轉賬了。