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ARC20

ARC-20合约#

ARC-20是在Alaya上通过智能合约实现代币API的一套标准，它提供的功能包括代币转账、查询代币余额以及网络上可用的代币总供应量等接口，与ERC-20完全兼容。

协议标准#

ARC-20协议是对可兑换同质代币（Fungible Tokens）定义的标准，同质代币每个Token与另外Token具有完全相同的类型和价值，该合约标准中规定了合约定义的函数、事件等，所有遵守这一标准编写的合约都被认为是一个ARC-20合约。

contract ARC20 {
    //required    function totalSupply() constant returns (uint theTotalSupply);    function balanceOf(address _owner) constant returns (uint balance);    function transfer(address _to, uint _value) returns (bool success);    function transferFrom(address _from, address _to, uint _value) returns (bool success);    function approve(address _spender, uint _value) returns (bool success);    function allowance(address _owner, address _spender) constant returns (uint remaining);        //optional    function name() public view returns (string);    function symbol() public view returns (string);    function decimals() public view returns (uint8);        //events    event Transfer(address indexed _from, address indexed _to, uint _value);    event Approval(address indexed _owner, address indexed _spender, uint _value);}

必须实现的接口#

  • totalSupply：该方法返回令牌总的发行量
  • balanceOf：该方法返回查询账户的令牌余额
  • transfer：该方法用来从智能合约地址里转账令牌到指定账户
  • approve：该方法用来授权第三方（例如Dapp）从令牌拥有者账户转账令牌
  • transferFrom：该方法可供第三方从令牌拥有者账户转账令牌，需要配合approve()方法使用
  • allowance：该方法用来查询可供第三方转账的查询账户的令牌余额

可选实现的接口#

  • name：返回令牌名称
  • symbol：返回令牌符号
  • decimals：返回令牌精度

事件#

  • Transfer：当通证被成功转账后，会触发Transfer转账事件，在链上记录转账信息日志
  • Approval：当approve()方法被成功调用后，会触发Approval事件，在链上记录授权信息日志

示例#

ARC-20标准与ERC-20完全兼容，示例可参考这里。

查看#

可以通过Alaya浏览器查看，也可以通过ATON查看ARC-20合约交易。

合约发行#

请参考Solidity合约入门手册。

调用方法#

以python为例：

安装依赖#

使用下列命令，安装 python library，建议 Python 版本3.7.5+:

pip install client-sdk-python

在安装过程中，部分依赖包会需要c++14 编译，请在看到相关提示后，下载cppbuildtools，使用默认值安装后，重新执行pip安装命令即可。

实例化合约#

from client_sdk_python import Web3, HTTPProvider
rpc, chain_id, hrp = 'http://127.0.0.1:6789', 201030, 'ATP'w3 = Web3(HTTPProvider(rpc), chain_id=chain_id, hrp_type=hrp)abi = [  {    "inputs":[      {"internalType":"uint256", "name":"initialSupply", "type":"uint256"},      {"internalType":"string", "name":"tokenName", "type":"string"},      {"internalType":"string", "name":"tokenSymbol", "type":"string"}    ],    "stateMutability":"nonpayable",    "type":"constructor"  },  {    "inputs":[],    "name":"totalSupply",    "outputs":[{"internalType":"uint256", "name":"", "type":"uint256"}],    "stateMutability":"view",    "type":"function"  },  {    "inputs":[{"internalType":"address", "name":"", "type":"address"}],    "name":"balanceOf",    "outputs":[{"internalType":"uint256", "name":"", "type":"uint256"}],    "stateMutability":"view",    "type":"function"  },  {    "inputs":[      {"internalType":"address", "name":"_to", "type":"address"},      {"internalType":"uint256", "name":"_value", "type":"uint256"}    ],    "name":"transfer",    "outputs":[{"internalType":"bool", "name":"success", "type":"bool"}],    "stateMutability":"nonpayable",    "type":"function"  },  {    "anonymous":false,    "inputs":[      {"indexed":true, "internalType":"address", "name":"from", "type":"address"},      {"indexed":true, "internalType":"address", "name":"to", "type":"address"},      {"indexed":false, "internalType":"uint256", "name":"value", "type":"uint256"}    ],    "name":"Transfer",    "type":"event"  }]                               # 合约abi内容arc20 = w3.eth.contract(address='contract address', abi=abi)# 查看合约所有的function 和 eventprint([func for func in arc20.functions])print([event for event in arc20.events])

查询合约信息#

以totalSupply、balanceOf示例，其他查询方法与此类似：

# 查询令牌的总发行量arc20.functions.totalSupply().call()# 查询账户的令牌余额arc20.functions.balanceOf('your address').call()

发送合约交易#

以transfer示例，其他交易方法与此类似：

# 转账令牌到指定账户tx = {    'chainId': w3.chain_id,    'nonce': w3.eth.getTransactionCount('your address'),    'gas': 4012388,    'value': 0,    'gasPrice': 1000000000,}txn = arc20.functions.transfer(to='to address', value=1 * 10 ** 18).buildTransaction(tx)signed_txn = w3.eth.account.signTransaction(txn, private_key='your private key')tx_hash = w3.eth.sendRawTransaction(signed_txn.rawTransaction).hex()receipt = w3.eth.waitForTransactionReceipt(tx_hash)

获取合约事件#

以transfer交易事件示例，其他事件获取方法与此类似：

events = arc20.events.Transfer().processReceipt(receipt)