给合约升级一下

原创

jetsan

发布于 2022-09-30 17:17:43

2960

发布于 2022-09-30 17:17:43

文章被收录于专栏：区块链相关开发

最近我在学习空投合约，学习资料中的合约样例非常的简单，就一个负责转账的函数，下面是合约代码：

Airdrop.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;
import "./IERC20.sol"; //import IERC20
contract Airdrop {
    function multiTransferToken(
    address _token,
    address[] calldata _addresses
    ) external {
        IERC20 token = IERC20(_token);
        uint _amountSum = _addresses.length * 100;
        require(token.allowance(msg.sender, address(this)) > _amountSum, "Need Approve ERC20 token");
        for (uint256 i; i < _addresses.length; i++) {
            token.transferFrom(msg.sender, _addresses[i], 100)
        }
    }
}

通过一番学习，现在我要来完善一下它，给它升级一下。

升级合约

首先，来分析一下需要完善的点：

发起空投得自己输入账户地址数组，如果数量多了，会很麻烦；解决思路：既然是空投合约，那么就应该是给主动参与活动的账户都投递空投，那就需要设置一个join函数让大家主动加入活动，获得奖励。
空投的代币数量固定，不够方便；解决思路：给每个参与空投的账户设置一个空投数量，用一个数组存储它们，还得能由合约拥有者进行设置，这样就更灵活了。

那么首先，要定义一个数组来存储参与空投的账户地址和它们对应的空投数量，在这里mapping就是很好的选择了：

mapping(address => uint) private _addresses;

之后，写一个参加活动的函数：

function join() public {
        payable(msg.sender).transfer(0);
        _add(msg.sender);
    }
function _add(address _address) private {
        require(_addresses[_address] == 0,"This address has already participated in the activity!");
        _addresses[_address] = 100;
        _addressArr.push(_address);
        _token.approve(_address,_addresses[_address]);
    }

接下来，我们写一个设置空投数量的函数：

function setAirdropNumber(address _address, unit num) public {
    require(msg.sender == owner,"you are not owner!")
    _addresses[_address] = num;
}

发起空投的函数也需要修改一番：

function multiTransferToken() external {
        uint _amountSum = _getSum(_addressArr);
        require(_token.balanceOf(address(this)) >= _amountSum, "Need enough ERC20 token");
        for (uint i; i < _addressArr.length; i++) {
            _token.transfer(_addressArr[i], _addresses[_addressArr[i]]);
        }
    }
function _getSum(address[] memory _arr) private view returns(uint sum){
        sum = 0;
        for(uint i = 0; i < _arr.length; i++){
            sum = sum + _addresses[_arr[i]];
        }
    }

根据以上的代码和需求，我对代码进一步进行完善，最终的代码就出现了：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;
import "./IERC20.sol"; //import IERC20
/// @notice 向多个地址转账ERC20代币
contract Airdrop {
    address private _owner;
    IERC20 private _token;
    mapping(address => uint) private _addresses;
    address[] private _addressArr;
    constructor(address tokenAddress) {
        _owner = msg.sender;
        _token = IERC20(tokenAddress);
    }
    function join() public {
        payable(msg.sender).transfer(0);
        _add(msg.sender);
    }
    function _add(address _address) private {
        require(_addresses[_address] == 0,"This address has already participated in the activity!");
        _addresses[_address] = 100 * (10 ** 18);
        _addressArr.push(_address);
        _token.approve(_address,_addresses[_address]);
    }
    function setAirdropNumber(address _address, uint num) public {
        require(_owner == msg.sender, "you are not owner!");
        _addresses[_address] = num;
        _token.approve(_address,_addresses[_address]);
    }
    function multiTransferToken() external {
        uint _amountSum = _getSum(_addressArr);
        require(_token.balanceOf(address(this)) >= _amountSum, "Need enough ERC20 token");
        for (uint i; i < _addressArr.length; i++) {
            _token.transfer(_addressArr[i], _addresses[_addressArr[i]]);
        }
    }
    function _getSum(address[] memory _arr) private view returns(uint sum){
        sum = 0;
        for(uint i = 0; i < _arr.length; i++){
            sum = sum + _addresses[_arr[i]];
        }
    }
}

现在，将新合约部署上链，测试一下吧。