diff --git a/33_Airdrop/Airdrop.sol b/33_Airdrop/Airdrop.sol index 161aaf38c..77b310461 100644 --- a/33_Airdrop/Airdrop.sol +++ b/33_Airdrop/Airdrop.sol @@ -6,6 +6,8 @@ import "./IERC20.sol"; //import IERC20 /// @notice 向多个地址转账ERC20代币 contract Airdrop { + mapping(address => uint) failTransferList; + /// @notice 向多个地址转账ERC20代币，使用前需要先授权 /// /// @param _token 转账的ERC20代币地址 @@ -15,14 +17,20 @@ contract Airdrop { address _token, address[] calldata _addresses, uint256[] calldata _amounts - ) external { + ) external { // 检查：_addresses和_amounts数组的长度相等 - require(_addresses.length == _amounts.length, "Lengths of Addresses and Amounts NOT EQUAL"); + require( + _addresses.length == _amounts.length, + "Lengths of Addresses and Amounts NOT EQUAL" + ); IERC20 token = IERC20(_token); // 声明IERC合约变量 uint _amountSum = getSum(_amounts); // 计算空投代币总量 // 检查：授权代币数量 > 空投代币总量 - require(token.allowance(msg.sender, address(this)) > _amountSum, "Need Approve ERC20 token"); - + require( + token.allowance(msg.sender, address(this)) > _amountSum, + "Need Approve ERC20 token" + ); + // for循环，利用transferFrom函数发送空投 for (uint256 i; i < _addresses.length; i++) { token.transferFrom(msg.sender, _addresses[i], _amounts[i]); @@ -35,47 +43,63 @@ contract Airdrop { uint256[] calldata _amounts ) public payable { // 检查：_addresses和_amounts数组的长度相等 - require(_addresses.length == _amounts.length, "Lengths of Addresses and Amounts NOT EQUAL"); + require( + _addresses.length == _amounts.length, + "Lengths of Addresses and Amounts NOT EQUAL" + ); uint _amountSum = getSum(_amounts); // 计算空投ETH总量 // 检查转入ETH等于空投总量 require(msg.value == _amountSum, "Transfer amount error"); // for循环，利用transfer函数发送ETH for (uint256 i = 0; i < _addresses.length; i++) { - _addresses[i].transfer(_amounts[i]); + // 注释代码有Dos攻击风险, 并且transfer 也是不推荐写法 + // Dos攻击 具体参考 https://github.com/AmazingAng/WTF-Solidity/blob/main/S09_DoS/readme.md + // _addresses[i].transfer(_amounts[i]); + (bool success, ) = _addresses[i].call{value: _amounts[i]}(""); + if (!success) { + failTransferList[_addresses[i]] = _amounts[i]; + } } } + // 给空投失败提供主动操作机会 + function withdrawFromFailList(address _to) public { + uint failAmount = failTransferList[msg.sender]; + require(failAmount > 0, "You are not in failed list"); + failTransferList[msg.sender] = 0; + (bool success, ) = _to.call{value: failAmount}(""); + require(success, "Fail withdraw"); + } // 数组求和函数 - function getSum(uint256[] calldata _arr) public pure returns(uint sum) - { - for(uint i = 0; i < _arr.length; i++) - sum = sum + _arr[i]; + function getSum(uint256[] calldata _arr) public pure returns (uint sum) { + for (uint i = 0; i < _arr.length; i++) sum = sum + _arr[i]; } } - // ERC20代币合约 contract ERC20 is IERC20 { - mapping(address => uint256) public override balanceOf; mapping(address => mapping(address => uint256)) public override allowance; - uint256 public override totalSupply; // 代币总供给 + uint256 public override totalSupply; // 代币总供给 + + string public name; // 名称 + string public symbol; // 符号 - string public name; // 名称 - string public symbol; // 符号 - uint8 public decimals = 18; // 小数位数 - constructor(string memory name_, string memory symbol_){ + constructor(string memory name_, string memory symbol_) { name = name_; symbol = symbol_; } // @dev 实现`transfer`函数，代币转账逻辑 - function transfer(address recipient, uint amount) external override returns (bool) { + function transfer( + address recipient, + uint amount + ) external override returns (bool) { balanceOf[msg.sender] -= amount; balanceOf[recipient] += amount; emit Transfer(msg.sender, recipient, amount); @@ -83,7 +107,10 @@ contract ERC20 is IERC20 { } // @dev 实现 `approve` 函数, 代币授权逻辑 - function approve(address spender, uint amount) external override returns (bool) { + function approve( + address spender, + uint amount + ) external override returns (bool) { allowance[msg.sender][spender] = amount; emit Approval(msg.sender, spender, amount); return true; @@ -115,5 +142,4 @@ contract ERC20 is IERC20 { totalSupply -= amount; emit Transfer(msg.sender, address(0), amount); } - } diff --git a/33_Airdrop/readme.md b/33_Airdrop/readme.md index c50957025..304ea538a 100644 --- a/33_Airdrop/readme.md +++ b/33_Airdrop/readme.md @@ -8,17 +8,17 @@ tags: - airdrop --- -# WTF Solidity极简入门: 33. 发送空投 +# WTF Solidity 极简入门: 33. 发送空投 -我最近在重新学solidity，巩固一下细节，也写一个“WTF Solidity极简入门”，供小白们使用（编程大佬可以另找教程），每周更新1-3讲。 +我最近在重新学 solidity，巩固一下细节，也写一个“WTF Solidity 极简入门”，供小白们使用（编程大佬可以另找教程），每周更新 1-3 讲。 欢迎关注我的推特：[@0xAA_Science](https://twitter.com/0xAA_Science) -欢迎加入WTF科学家社区，内有加微信群方法：[链接](https://discord.gg/5akcruXrsk) +欢迎加入 WTF 科学家社区，内有加微信群方法：[链接](https://discord.gg/5akcruXrsk) -所有代码和教程开源在github（1024个star发课程认证，2048个star发社群NFT）: [github.com/AmazingAng/WTFSolidity](https://github.com/AmazingAng/WTFSolidity) +所有代码和教程开源在 github（1024 个 star 发课程认证，2048 个 star 发社群 NFT）: [github.com/AmazingAng/WTFSolidity](https://github.com/AmazingAng/WTFSolidity) ------ +--- 在币圈，最开心的一件事就是领空投，空手套白狼。这一讲，我们将学习如何使用智能合约发送`ERC20`代币空投。 @@ -34,68 +34,76 @@ tags: - `getSum()`函数：返回`uint`数组的和。 - ```solidity - // 数组求和函数 - function getSum(uint256[] calldata _arr) public pure returns(uint sum) - { - for(uint i = 0; i < _arr.length; i++) - sum = sum + _arr[i]; - } - ``` + ```solidity + // 数组求和函数 + function getSum(uint256[] calldata _arr) public pure returns(uint sum) + { + for(uint i = 0; i < _arr.length; i++) + sum = sum + _arr[i]; + } + ``` - `multiTransferToken()`函数：发送`ERC20`代币空投，包含`3`个参数： - - `_token`：代币合约地址（`address`类型） - - `_addresses`：接收空投的用户地址数组（`address[]`类型） - - `_amounts`：空投数量数组，对应`_addresses`里每个地址的数量（`uint[]`类型） - - 该函数有两个检查：第一个`require`检查了`_addresses`和`_amounts`两个数组长度是否相等；第二个`require`检查了空投合约的授权额度大于要空投的代币数量总和。 - - ```solidity - /// @notice 向多个地址转账ERC20代币，使用前需要先授权 - /// - /// @param _token 转账的ERC20代币地址 - /// @param _addresses 空投地址数组 - /// @param _amounts 代币数量数组（每个地址的空投数量） - function multiTransferToken( - address _token, - address[] calldata _addresses, - uint256[] calldata _amounts - ) external { - // 检查：_addresses和_amounts数组的长度相等 - require(_addresses.length == _amounts.length, "Lengths of Addresses and Amounts NOT EQUAL"); - IERC20 token = IERC20(_token); // 声明IERC合约变量 - uint _amountSum = getSum(_amounts); // 计算空投代币总量 - // 检查：授权代币数量 >= 空投代币总量 - require(token.allowance(msg.sender, address(this)) >= _amountSum, "Need Approve ERC20 token"); - - // for循环，利用transferFrom函数发送空投 - for (uint8 i; i < _addresses.length; i++) { - token.transferFrom(msg.sender, _addresses[i], _amounts[i]); - } - } - ``` + + - `_token`：代币合约地址（`address`类型） + - `_addresses`：接收空投的用户地址数组（`address[]`类型） + - `_amounts`：空投数量数组，对应`_addresses`里每个地址的数量（`uint[]`类型） + + 该函数有两个检查：第一个`require`检查了`_addresses`和`_amounts`两个数组长度是否相等；第二个`require`检查了空投合约的授权额度大于要空投的代币数量总和。 + + ```solidity + /// @notice 向多个地址转账ERC20代币，使用前需要先授权 + /// + /// @param _token 转账的ERC20代币地址 + /// @param _addresses 空投地址数组 + /// @param _amounts 代币数量数组（每个地址的空投数量） + function multiTransferToken( + address _token, + address[] calldata _addresses, + uint256[] calldata _amounts + ) external { + // 检查：_addresses和_amounts数组的长度相等 + require(_addresses.length == _amounts.length, "Lengths of Addresses and Amounts NOT EQUAL"); + IERC20 token = IERC20(_token); // 声明IERC合约变量 + uint _amountSum = getSum(_amounts); // 计算空投代币总量 + // 检查：授权代币数量 >= 空投代币总量 + require(token.allowance(msg.sender, address(this)) >= _amountSum, "Need Approve ERC20 token"); + + // for循环，利用transferFrom函数发送空投 + for (uint8 i; i < _addresses.length; i++) { + token.transferFrom(msg.sender, _addresses[i], _amounts[i]); + } + } + ``` - `multiTransferETH()`函数：发送`ETH`空投，包含`2`个参数： - - `_addresses`：接收空投的用户地址数组（`address[]`类型） - - `_amounts`：空投数量数组，对应`_addresses`里每个地址的数量（`uint[]`类型） - - ```solidity - /// 向多个地址转账ETH - function multiTransferETH( - address payable[] calldata _addresses, - uint256[] calldata _amounts - ) public payable { - // 检查：_addresses和_amounts数组的长度相等 - require(_addresses.length == _amounts.length, "Lengths of Addresses and Amounts NOT EQUAL"); - uint _amountSum = getSum(_amounts); // 计算空投ETH总量 - // 检查转入ETH等于空投总量 - require(msg.value == _amountSum, "Transfer amount error"); - // for循环，利用transfer函数发送ETH - for (uint256 i = 0; i < _addresses.length; i++) { - _addresses[i].transfer(_amounts[i]); - } - } - ``` + + - `_addresses`：接收空投的用户地址数组（`address[]`类型） + - `_amounts`：空投数量数组，对应`_addresses`里每个地址的数量（`uint[]`类型） + + ```solidity + /// 向多个地址转账ETH + function multiTransferETH( + address payable[] calldata _addresses, + uint256[] calldata _amounts + ) public payable { + // 检查：_addresses和_amounts数组的长度相等 + require(_addresses.length == _amounts.length, "Lengths of Addresses and Amounts NOT EQUAL"); + uint _amountSum = getSum(_amounts); // 计算空投ETH总量 + // 检查转入ETH等于空投总量 + require(msg.value == _amountSum, "Transfer amount error"); + // for循环，利用transfer函数发送ETH + for (uint256 i = 0; i < _addresses.length; i++) { + // 注释代码有Dos攻击风险, 并且transfer 也是不推荐写法 + // Dos攻击 具体参考 https://github.com/AmazingAng/WTF-Solidity/blob/main/S09_DoS/readme.md + // _addresses[i].transfer(_amounts[i]); + (bool success, ) = _addresses[i].call{value: _amounts[i]}(""); + if (!success) { + failTransferList[_addresses[i]] = _amounts[i]; + } + } + } + ``` ### 空投实践 @@ -109,7 +117,7 @@ tags: ![部署`Airdrop`合约](./img/33-3.png) -3. 利用`ERC20`代币合约中的`approve()`函数，给`Airdrop`空投合约授权10000 单位代币。 +3. 利用`ERC20`代币合约中的`approve()`函数，给`Airdrop`空投合约授权 10000 单位代币。 ![授权`Airdrop`合约](./img/33-4.png) @@ -131,4 +139,4 @@ tags: ## 总结 -这一讲，我们介绍了如何使用`solidity`写`ERC20`代币空投合约，极大增加空投效率。我撸空投收获最大的一次是`ENS`空投，你们呢？ \ No newline at end of file +这一讲，我们介绍了如何使用`solidity`写`ERC20`代币空投合约，极大增加空投效率。我撸空投收获最大的一次是`ENS`空投，你们呢？