Solidity 智慧合約完整實作範例指南：從基礎架構到安全設計的工程實踐
本文提供完整的Solidity智慧合約實作範例，涵蓋ERC-20代幣合約、ERC-721 NFT合約、借貸協議、AMM去中心化交易所、DAO治理合約、可升級代理模式、速率限制器等核心類型。每個範例包含詳細的程式碼註釋、安全檢查說明、以及Gas優化技巧，是區塊鏈工程師必備的實作參考手冊。
Solidity 智慧合約完整實作範例指南：從基礎架構到安全設計的工程實踐
概述
本文提供完整的 Solidity 智慧合約實作範例，涵蓋從基礎合約架構到複雜 DeFi 協議的完整程式碼。我們將深入分析各種常見合約模式的設計原理、安全考量與實際應用，包括代幣合約、借貸協議、DEX 交易對、保險庫、治理合約等核心類型。每個範例都包含詳細的程式碼註釋、安全檢查說明、以及 Gas 優化技巧。
Solidity 是以太坊智慧合約開發的主要程式語言，自 2014 年誕生以來經歷了多次重大版本更新。截至 2026 年第一季度，以太坊網路上已部署超過 5000 萬個智慧合約，總鎖定價值（TVL）超過 2000 億美元。掌握 Solidity 實作技術對於區塊鏈工程師而言至關重要。
第一章：代幣合約實作
1.1 ERC-20 代幣合約
ERC-20 是以太坊最重要的代幣標準，定義了代幣轉移、授權、餘額查詢等基本接口。
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @title ERC20 代幣合約完整實現
* @dev 包含所有 ERC-20 標準接口和擴展功能
*/
contract ERC20Token {
// ============ 事件定義 ============
// 轉帳事件
event Transfer(address indexed from, address indexed to, uint256 value);
// 授權事件
event Approval(address indexed owner, address indexed spender, uint256 value);
// 鑄造事件（擴展）
event Mint(address indexed to, uint256 amount);
// 銷毀事件（擴展）
event Burn(address indexed from, uint256 amount);
// ============ 狀態變數 ============
// 代幣名稱
string public name;
// 代幣符號
string public symbol;
// 代幣精度（小數位數）
uint8 public decimals;
// 總供應量
uint256 public totalSupply;
// 餘額映射：地址 => 餘額
mapping(address => uint256) public balanceOf;
// 授權映射：所有者 => 獲授權者 => 授權金額
mapping(address => mapping(address => uint256)) public allowance;
// 不可轉帳地址清單（黑名單）
mapping(address => bool) public isBlacklisted;
// 暫停標記
bool public paused = false;
// 合約所有者
address public owner;
// ============ 修飾符 ============
// 僅所有者
modifier onlyOwner() {
require(msg.sender == owner, "Not the owner");
_;
}
// 檢查暫停狀態
modifier whenNotPaused() {
require(!paused, "Contract is paused");
_;
}
// 檢查黑名單
modifier notBlacklisted(address account) {
require(!isBlacklisted[account], "Account is blacklisted");
_;
}
// ============ 建構函數 ============
/**
* @dev 建構函數，初始化代幣參數
* @param _name 代幣名稱
* @param _symbol 代幣符號
* @param _decimals 小數位數
* @param _initialSupply 初始供應量
*/
constructor(
string memory _name,
string memory _symbol,
uint8 _decimals,
uint256 _initialSupply
) {
require(_initialSupply > 0, "Initial supply must be greater than 0");
name = _name;
symbol = _symbol;
decimals = _decimals;
// 創建者獲得所有初始供應量
owner = msg.sender;
balanceOf[owner] = _initialSupply * (10 ** uint256(_decimals));
totalSupply = _initialSupply * (10 ** uint256(_decimals));
emit Transfer(address(0), owner, totalSupply);
}
// ============ 核心功能 ============
/**
* @dev 轉帳功能
* @param to 收款地址
* @param amount 轉帳金額
*/
function transfer(
address to,
uint256 amount
) public whenNotPaused notBlacklisted(msg.sender) notBlacklisted(to) returns (bool) {
require(to != address(0), "Transfer to zero address");
require(amount > 0, "Transfer amount must be greater than 0");
require(balanceOf[msg.sender] >= amount, "Insufficient balance");
// 扣除轉帳者餘額
balanceOf[msg.sender] -= amount;
// 增加收款者餘額
balanceOf[to] += amount;
emit Transfer(msg.sender, to, amount);
return true;
}
/**
* @dev 授權功能
* @param spender 獲授權地址
* @param amount 授權金額
*/
function approve(
address spender,
uint256 amount
) public whenNotPaused notBlacklisted(msg.sender) notBlacklisted(spender) returns (bool) {
require(spender != address(0), "Approve to zero address");
allowance[msg.sender][spender] = amount;
emit Approval(msg.sender, spender, amount);
return true;
}
/**
* @dev 轉帳並從授權餘額扣除
* @param from 轉出地址
* @param to 轉入地址
* @param amount 轉帳金額
*/
function transferFrom(
address from,
address to,
uint256 amount
) public whenNotPaused
notBlacklisted(msg.sender)
notBlacklisted(from)
notBlacklisted(to)
returns (bool) {
require(to != address(0), "Transfer to zero address");
require(amount > 0, "Transfer amount must be greater than 0");
require(balanceOf[from] >= amount, "Insufficient balance");
require(allowance[from][msg.sender] >= amount, "Allowance exceeded");
// 扣除轉出者餘額
balanceOf[from] -= amount;
// 增加轉入者餘額
balanceOf[to] += amount;
// 扣除授權餘額
allowance[from][msg.sender] -= amount;
emit Transfer(from, to, amount);
return true;
}
/**
* @dev 增加授權金額（安全擴展）
* @param spender 獲授權地址
* @param addedValue 增加的金額
*/
function increaseAllowance(
address spender,
uint256 addedValue
) public whenNotPaused notBlacklisted(msg.sender) notBlacklisted(spender) returns (bool) {
require(spender != address(0), "Approve to zero address");
allowance[msg.sender][spender] += addedValue;
emit Approval(msg.sender, spender, allowance[msg.sender][spender]);
return true;
}
/**
* @dev 減少授權金額
* @param spender 獲授權地址
* @param subtractedValue 減少的金額
*/
function decreaseAllowance(
address spender,
uint256 subtractedValue
) public whenNotPaused returns (bool) {
require(spender != address(0), "Approve to zero address");
require(
allowance[msg.sender][spender] >= subtractedValue,
"Decreased allowance below zero"
);
allowance[msg.sender][spender] -= subtractedValue;
emit Approval(msg.sender, spender, allowance[msg.sender][spender]);
return true;
}
// ============ 擴展功能 ============
/**
* @dev 鑄造新代幣（僅所有者）
* @param account 接收地址
* @param amount 鑄造數量
*/
function mint(
address account,
uint256 amount
) external onlyOwner whenNotPaused notBlacklisted(account) {
require(account != address(0), "Mint to zero address");
totalSupply += amount;
balanceOf[account] += amount;
emit Mint(account, amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev 銷毀代幣
* @param amount 銷毀數量
*/
function burn(uint256 amount) external whenNotPaused notBlacklisted(msg.sender) {
require(amount > 0, "Burn amount must be greater than 0");
require(balanceOf[msg.sender] >= amount, "Insufficient balance");
balanceOf[msg.sender] -= amount;
totalSupply -= amount;
emit Burn(msg.sender, amount);
emit Transfer(msg.sender, address(0), amount);
}
/**
* @dev 從指定帳戶銷毀代幣（僅所有者）
* @param account 帳戶地址
* @param amount 銷毀數量
*/
function burnFrom(
address account,
uint256 amount
) external onlyOwner whenNotPaused {
require(balanceOf[account] >= amount, "Insufficient balance");
balanceOf[account] -= amount;
totalSupply -= amount;
emit Burn(account, amount);
emit Transfer(account, address(0), amount);
}
// ============ 管理功能 ============
/**
* @dev 暫停合約
*/
function pause() external onlyOwner {
paused = true;
}
/**
* @dev 解除暫停
*/
function unpause() external onlyOwner {
paused = false;
}
/**
* @dev 將帳戶加入黑名單
* @param account 帳戶地址
*/
function blacklist(address account) external onlyOwner {
require(account != owner, "Cannot blacklist owner");
isBlacklisted[account] = true;
}
/**
* @dev 將帳戶移出黑名單
* @param account 帳戶地址
*/
function unblacklist(address account) external onlyOwner {
isBlacklisted[account] = false;
}
// ============ 工具函數 ============
/**
* @dev 計算地址的 ERC-165 接口 ID
*/
function supportsInterface(bytes4 interfaceId) external pure returns (bool) {
return interfaceId == 0x36372b07; // ERC-20 interface ID
}
}1.2 ERC-721 NFT 合約
ERC-721 是非同質化代幣（NFT）的標準，每個代幣 ID 都是唯一的。
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @title ERC721 NFT 合約完整實現
*/
contract NFTContract {
// ============ 事件 ============
event Transfer(
address indexed from,
address indexed to,
uint256 indexed tokenId
);
event Approval(
address indexed owner,
address indexed approved,
uint256 indexed tokenId
);
event ApprovalForAll(
address indexed owner,
address indexed operator,
bool approved
);
// ============ 狀態變數 ============
// 代幣名稱
string public name;
// 代幣符號
string public symbol;
// 代幣 URI 基礎路徑
string public baseURI;
// 每個代幣的元數據 URI
mapping(uint256 => string) public tokenURI;
// 代幣 ID 到所有者的映射
mapping(uint256 => address) public ownerOf;
// 地址到餘額的映射
mapping(address => uint256) public balanceOf;
// 代幣 ID 到授權地址的映射
mapping(uint256 => address) public getApproved;
// 地址到運營商映射（批量授權）
mapping(address => mapping(address => bool)) public isApprovedForAll;
// ============ 計數器 ============
// 當前代幣 ID
uint256 private _currentTokenId;
// ============ 建構函數 ============
constructor(string memory _name, string memory _symbol, string memory _baseURI) {
name = _name;
symbol = _symbol;
baseURI = _baseURI;
}
// ============ 核心功能 ============
/**
* @dev 鑄造新 NFT
* @param to 接收地址
* @param uri 元數據 URI
*/
function mint(
address to,
string memory uri
) external returns (uint256) {
require(to != address(0), "Mint to zero address");
uint256 tokenId = _currentTokenId;
_currentTokenId++;
// 設置所有權
_mint(to, tokenId);
// 設置元數據
tokenURI[tokenId] = uri;
return tokenId;
}
/**
* @dev 內部鑄造函數
*/
function _mint(address to, uint256 tokenId) internal {
require(ownerOf[tokenId] == address(0), "Token already minted");
ownerOf[tokenId] = to;
balanceOf[to]++;
emit Transfer(address(0), to, tokenId);
}
/**
* @dev 轉移 NFT
*/
function transferFrom(
address from,
address to,
uint256 tokenId
) external {
require(
_isApprovedOrOwner(msg.sender, tokenId),
"Not approved or owner"
);
_transfer(from, to, tokenId);
}
/**
* @dev 安全轉移（含接收回調）
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes memory data
) external {
require(
_isApprovedOrOwner(msg.sender, tokenId),
"Not approved or owner"
);
_safeTransfer(from, to, tokenId, data);
}
/**
* @dev 授權單個 NFT
*/
function approve(address to, uint256 tokenId) external {
address owner = ownerOf[tokenId];
require(to != owner, "Approval to current owner");
require(
msg.sender == owner || isApprovedForAll[owner][msg.sender],
"Not owner or approved for all"
);
getApproved[tokenId] = to;
emit Approval(owner, to, tokenId);
}
/**
* @dev 設置運營商（批量授權）
*/
function setApprovalForAll(address operator, bool approved) external {
require(msg.sender != operator, "Approve to caller");
isApprovedForAll[msg.sender][operator] = approved;
emit ApprovalForAll(msg.sender, operator, approved);
}
// ============ 內部函數 ============
/**
* @dev 執行轉移
*/
function _transfer(
address from,
address to,
uint256 tokenId
) internal {
require(
ownerOf[tokenId] == from,
"Transfer from incorrect owner"
);
// 清除授權
delete getApproved[tokenId];
// 更新餘額
balanceOf[from]--;
balanceOf[to]++;
// 更新所有權
ownerOf[tokenId] = to;
emit Transfer(from, to, tokenId);
}
/**
* @dev 安全轉移（含接收回調）
*/
function _safeTransfer(
address from,
address to,
uint256 tokenId,
bytes memory data
) internal {
_transfer(from, to, tokenId);
// 檢查接收合約（若為 EOA 则跳过）
if (to.code.length > 0) {
// 調用 IERC721Receiver 接口
// 實際實現需要檢查返回值
}
}
/**
* @dev 檢查是否已授權
*/
function _isApprovedOrOwner(
address spender,
uint256 tokenId
) internal view returns (bool) {
address owner = ownerOf[tokenId];
return (
spender == owner ||
getApproved[tokenId] == spender ||
isApprovedForAll[owner][spender]
);
}
}第二章：借貸協議實作
2.1 簡化借貸合約
這是一個基礎的借貸協議合約，支援存款、借款和清算功能。
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @title 簡化借貸協議合約
* @dev 實現基本的抵押借貸功能
*/
contract SimpleLendingProtocol {
// ============ 事件 ============
event Deposit(address indexed user, uint256 amount);
event Withdraw(address indexed user, uint256 amount);
event Borrow(address indexed user, uint256 amount, uint256 collateralAmount);
event Repay(address indexed user, uint256 amount);
event Liquidate(
address indexed liquidator,
address indexed borrower,
uint256 debtAmount,
uint256 collateralAmount
);
// ============ 狀態變數 ============
// 代幣地址
address public immutable collateralToken; // 抵押代幣（ETH 或 WETH）
address public immutable debtToken; // 債務代幣
// 利率參數
uint256 public constant BORROW_RATE = 0.05e18; // 年化 5%
uint256 public constant COLLATERAL_FACTOR = 0.75e18; // 抵押率 75%
uint256 public constant LIQUIDATION_THRESHOLD = 0.8e18; // 清算閾值 80%
uint256 public constant LIQUIDATION_BONUS = 1.1e18; // 清算獎勵 10%
// 用戶存款
mapping(address => uint256) public deposits;
// 用戶借款
mapping(address => uint256) public borrows;
// 用戶抵押額
mapping(address => uint256) public collateral;
// 借款累計利息
uint256 public totalBorrows;
// 上次更新時間
uint256 public lastUpdateTimestamp;
// ============ 修飾符 ============
modifier updateInterest() {
_accrueInterest();
_;
}
// ============ 建構函數 ============
constructor(address _collateralToken, address _debtToken) {
require(_collateralToken != address(0), "Invalid collateral token");
require(_debtToken != address(0), "Invalid debt token");
collateralToken = _collateralToken;
debtToken = _debtToken;
lastUpdateTimestamp = block.timestamp;
}
// ============ 存款功能 ============
/**
* @dev 存款功能
* @param amount 存款金額
*/
function deposit(uint256 amount) external updateInterest {
require(amount > 0, "Deposit amount must be greater than 0");
// 假設已經透過代幣轉帳將代幣存入合約
// 實際實現需要使用 IERC20.safeTransferFrom
deposits[msg.sender] += amount;
collateral[msg.sender] += amount;
emit Deposit(msg.sender, amount);
}
/**
* @dev 提款功能
* @param amount 提款金額
*/
function withdraw(uint256 amount) external updateInterest {
require(amount > 0, "Withdraw amount must be greater than 0");
require(deposits[msg.sender] >= amount, "Insufficient deposit");
// 檢查提款後健康度
if (borrows[msg.sender] > 0) {
require(
_getHealthFactor(msg.sender) >= 1e18,
"Health factor too low"
);
}
deposits[msg.sender] -= amount;
collateral[msg.sender] -= amount;
// 轉出代幣
// 實際實現需要使用 IERC20.safeTransfer
emit Withdraw(msg.sender, amount);
}
// ============ 借款功能 ============
/**
* @dev 借款功能
* @param amount 借款金額
*/
function borrow(uint256 amount) external updateInterest {
require(amount > 0, "Borrow amount must be greater than 0");
// 檢查健康度
uint256 maxBorrow = (collateral[msg.sender] * COLLATERAL_FACTOR) / 1e18;
require(
borrows[msg.sender] + amount <= maxBorrow,
"Borrow amount exceeds limit"
);
borrows[msg.sender] += amount;
totalBorrows += amount;
// 轉出借出的代幣
// 實際實現需要使用 IERC20.safeTransfer
emit Borrow(msg.sender, amount, collateral[msg.sender]);
}
/**
* @dev 還款功能
* @param amount 還款金額
*/
function repay(uint256 amount) external updateInterest {
require(amount > 0, "Repay amount must be greater than 0");
require(borrows[msg.sender] > 0, "No outstanding debt");
// 計算應還金額（含利息）
uint256 repayAmount = amount > borrows[msg.sender]
? borrows[msg.sender]
: amount;
borrows[msg.sender] -= repayAmount;
totalBorrows -= repayAmount;
// 從借款人收取代幣
// 實際實現需要使用 IERC20.safeTransferFrom
emit Repay(msg.sender, repayAmount);
}
// ============ 清算功能 ============
/**
* @dev 清算功能
* @param borrower 借款人地址
*/
function liquidate(address borrower) external updateInterest {
require(borrows[borrower] > 0, "No debt to liquidate");
// 檢查健康度
require(
_getHealthFactor(borrower) < LIQUIDATION_THRESHOLD,
"Health factor above threshold"
);
// 計算清算金額（清償全部債務）
uint256 debtAmount = borrows[borrower];
// 計算可獲得的抵押品
uint256 collateralAmount = (debtAmount * LIQUIDATION_BONUS) / 1e18;
require(
collateral[borrower] >= collateralAmount,
"Insufficient collateral"
);
// 清除債務
borrows[borrower] = 0;
totalBorrows -= debtAmount;
// 轉移抵押品
collateral[borrower] -= collateralAmount;
deposits[borrower] -= collateralAmount;
// 清算人獲得抵押品
// 實際實現需要轉移代幣
emit Liquidate(
msg.sender,
borrower,
debtAmount,
collateralAmount
);
}
// ============ 利息計算 ============
/**
* @dev 累計利息
*/
function _accrueInterest() internal {
uint256 timeElapsed = block.timestamp - lastUpdateTimestamp;
if (timeElapsed > 0 && totalBorrows > 0) {
// 簡單利息計算：日利率 = 年利率 / 365
uint256 interest = (totalBorrows * BORROW_RATE * timeElapsed) /
(365 days * 1e18);
totalBorrows += interest;
lastUpdateTimestamp = block.timestamp;
}
}
/**
* @dev 計算健康度
*/
function _getHealthFactor(address user) internal view returns (uint256) {
if (borrows[user] == 0) {
return type(uint256).max;
}
// 健康度 = 抵押價值 / 債務價值
uint256 collateralValue = (collateral[user] * COLLATERAL_FACTOR) / 1e18;
uint256 healthFactor = (collateralValue * 1e18) / borrows[user];
return healthFactor;
}
// ============ 查詢函數 ============
/**
* @dev 獲取用戶健康度
*/
function getHealthFactor(address user) external view returns (uint256) {
return _getHealthFactor(user);
}
/**
* @dev 獲取最大借款額
*/
function getMaxBorrow(address user) external view returns (uint256) {
return (collateral[user] * COLLATERAL_FACTOR) / 1e18 - borrows[user];
}
}第三章：去中心化交易所實作
3.1 簡化 AMM 交易對合約
這是 Uniswap V2 風格的 AMM 交易對合約核心實現。
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @title 簡化 AMM 交易對合約
* @dev 實現 x * y = k 常數乘積公式
*/
contract AMMPair {
// ============ 事件 ============
event Mint(address indexed sender, uint256 amount0, uint256 amount1);
event Burn(
address indexed sender,
uint256 amount0,
uint256 amount1,
address indexed to
);
event Swap(
address indexed sender,
uint256 amount0In,
uint256 amount1In,
uint256 amount0Out,
uint256 amount1Out,
address indexed to
);
// ============ 狀態變數 ============
// 代幣地址
address public immutable token0;
address public immutable token1;
// 儲備量
uint256 public reserve0;
uint256 public reserve1;
// 累積價格（用於 Oracle 功能）
uint256 public price0CumulativeLast;
uint256 public price1CumulativeLast;
// 最後更新區塊時間戳
uint256 public lastBlockTimestamp;
// 流動性代幣（LP Token）
string public constant lpTokenName = "AMM LP Token";
string public constant lpTokenSymbol = "AMM-LP";
uint8 public constant lpTokenDecimals = 18;
uint256 public totalSupply;
mapping(address => uint256) public balanceOf;
// ============ 建構函數 ============
constructor(address _token0, address _token1) {
require(_token0 != address(0), "Invalid token0");
require(_token1 != address(0), "Invalid token1");
require(_token0 != _token1, "Identical addresses");
token0 = _token0;
token1 = _token1;
}
// ============ 流動性功能 ============
/**
* @dev 添加流動性
* @param amount0Desired 期望的代幣0數量
* @param amount1Desired 期望的代幣1數量
* @param amount0Min 最小代幣0數量
* @param amount1Min 最小代幣1數量
* @param to 流動性代幣接收地址
* @return amount0 實際添加的代幣0數量
* @return amount1 實際添加的代幣1數量
* @return liquidity 鑄造的流動性代幣數量
*/
function addLiquidity(
uint256 amount0Desired,
uint256 amount1Desired,
uint256 amount0Min,
uint256 amount1Min,
address to
) external returns (
uint256 amount0,
uint256 amount1,
uint256 liquidity
) {
// 計算輸入數量
if (reserve0 == 0 && reserve1 == 0) {
amount0 = amount0Desired;
amount1 = amount1Desired;
} else {
// 根據現有比例計算
uint256 amount1Optimal = (amount0Desired * reserve1) / reserve0;
if (amount1Optimal <= amount1Desired) {
require(amount1Optimal >= amount1Min, "Insufficient amount1");
amount0 = amount0Desired;
amount1 = amount1Optimal;
} else {
uint256 amount0Optimal = (amount1Desired * reserve0) / reserve1;
assert(amount0Optimal <= amount0Desired);
require(amount0Optimal >= amount0Min, "Insufficient amount0");
amount0 = amount0Optimal;
amount1 = amount1Desired;
}
}
// 轉入代幣（需要先授權）
// 實際實現需要 safeTransferFrom
// 更新儲備量
reserve0 += amount0;
reserve1 += amount1;
// 計算並鑄造流動性代幣
if (totalSupply == 0) {
// 初始鑄造：sqrt(x * y)
liquidity = _sqrt(amount0 * amount1);
} else {
// 根據份額比例鑄造
liquidity = _min(
(amount0 * totalSupply) / reserve0,
(amount1 * totalSupply) / reserve1
);
}
require(liquidity > 0, "Insufficient liquidity minted");
_mint(to, liquidity);
emit Mint(to, amount0, amount1);
}
/**
* @dev 移除流動性
* @param liquidity 移除的流動性代幣數量
* @param amount0Min 最小收到代幣0數量
* @param amount1Min 最小收到代幣1數量
* @param to 代幣接收地址
* @return amount0 收到的代幣0數量
* @return amount1 收到的代幣1數量
*/
function removeLiquidity(
uint256 liquidity,
uint256 amount0Min,
uint256 amount1Min,
address to
) external returns (uint256 amount0, uint256 amount1) {
require(liquidity > 0, "Invalid liquidity amount");
// 計算可提取的代幣數量
amount0 = (liquidity * reserve0) / totalSupply;
amount1 = (liquidity * reserve1) / totalSupply;
require(amount0 >= amount0Min, "Insufficient amount0 received");
require(amount1 >= amount1Min, "Insufficient amount1 received");
// 銷毀流動性代幣
_burn(msg.sender, liquidity);
// 更新儲備量
reserve0 -= amount0;
reserve1 -= amount1;
// 轉出代幣
// 實際實現需要 safeTransfer
emit Burn(to, amount0, amount1, to);
}
// ============ 交易功能 ============
/**
* @dev 交換代幣
* @param amount0Out 輸出代幣0數量
* @param amount1Out 輸出代幣1數量
* @param to 接收地址
* @param data 回調數據
*/
function swap(
uint256 amount0Out,
uint256 amount1Out,
address to,
bytes calldata data
) external {
require(amount0Out > 0 || amount1Out > 0, "Invalid output amount");
// 檢查儲備
require(
amount0Out < reserve0 && amount1Out < reserve1,
"Insufficient liquidity"
);
// 計算輸入數量（透過代幣轉入）
// 實際實現需要追蹤轉入數量
uint256 amount0In = 0;
uint256 amount1In = 0;
// 計算輸出（使用常數乘積公式）
// k = reserve0 * reserve1
// (reserve0 + amount0In - fee) * (reserve1 + amount1In - amount1Out) = k
//
// 簡化計算（不考慮費用）
if (amount0Out > 0) {
// 用 token0 交換 token1
require(amount1In > 0, "Insufficient input amount");
// 更新儲備
reserve0 = reserve0 + amount0In - amount0Out;
reserve1 = reserve1 + amount1In - amount1Out;
} else if (amount1Out > 0) {
// 用 token1 交換 token0
require(amount0In > 0, "Insufficient input amount");
// 更新儲備
reserve0 = reserve0 + amount0In - amount0Out;
reserve1 = reserve1 + amount1In - amount1Out;
}
// 轉出代幣
if (amount0Out > 0) {
// 實際實現需要 safeTransfer
}
if (amount1Out > 0) {
// 實際實現需要 safeTransfer
}
emit Swap(
msg.sender,
amount0In,
amount1In,
amount0Out,
amount1Out,
to
);
}
// ============ 內部函數 ============
/**
* @dev 鑄造流動性代幣
*/
function _mint(address to, uint256 amount) internal {
balanceOf[to] += amount;
totalSupply += amount;
}
/**
* @dev 銷毀流動性代幣
*/
function _burn(address from, uint256 amount) internal {
balanceOf[from] -= amount;
totalSupply -= amount;
}
/**
* @dev 平方根函數
*/
function _sqrt(uint256 y) internal pure returns (uint256 z) {
if (y > 3) {
z = y;
uint256 x = y / 2 + 1;
while (x < z) {
z = x;
x = (y / x + x) / 2;
}
} else if (y != 0) {
z = 1;
}
}
/**
* @dev 最小值函數
*/
function _min(uint256 x, uint256 y) internal pure returns (uint256) {
return x < y ? x : y;
}
}第四章：治理合約實作
4.1 DAO 治理合約
這是一個簡化的 DAO 治理合約，實現提案、投票、執行功能。
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @title 簡化 DAO 治理合約
* @dev 實現提案創建、投票、執行功能
*/
contract Governance {
// ============ 事件 ============
event ProposalCreated(
uint256 indexed proposalId,
address indexed proposer,
string description,
address[] targets,
uint256[] values,
bytes[] calldatas,
uint256 startBlock,
uint256 endBlock
);
event VoteCast(
address indexed voter,
uint256 indexed proposalId,
uint8 support,
uint256 weight,
string reason
);
event ProposalExecuted(
uint256 indexed proposalId,
uint256 executionTimestamp
);
event ProposalCancelled(uint256 indexed proposalId);
// ============ 提案狀態 ============
enum ProposalState {
Pending,
Active,
Canceled,
Defeated,
Succeeded,
Executed,
Expired
}
// ============ 提案結構 ============
struct Proposal {
// 提案描述
string description;
// 目標合約列表
address[] targets;
// 調用的 ETH 數量
uint256[] values;
// 調用數據
bytes[] calldatas;
// 投票開始區塊
uint256 startBlock;
// 投票結束區塊
uint256 endBlock;
// 投票計數
uint256 forVotes;
uint256 againstVotes;
uint256 abstainVotes;
// 執行標記
bool executed;
// 取消標記
bool canceled;
// 提案人
address proposer;
// 投票者列表（用於防止重複投票）
mapping(address => bool) hasVoted;
}
// ============ 狀態變數 ============
// 治理代幣地址
address public immutable governanceToken;
// 提案門檻（創建提案所需的代幣數量）
uint256 public proposalThreshold;
// 投票延遲（提案創建後多少區塊才能開始投票）
uint256 public votingDelay;
// 投票持續時間（多少區塊）
uint256 public votingPeriod;
// 通過門檻（投票總數的百分比）
uint256 public constant QUORUM_THRESHOLD = 0.04e18; // 4%
// 提案映射
mapping(uint256 => Proposal) public proposals;
// 提案計數
uint256 public proposalCount;
// ============ 修飾符 ============
modifier onlyTokenHolder() {
// 檢查治理代幣餘額
// 實際實現需要調用 IERC20.balanceOf
_;
}
// ============ 建構函數 ============
constructor(
address _governanceToken,
uint256 _proposalThreshold,
uint256 _votingDelay,
uint256 _votingPeriod
) {
require(_governanceToken != address(0), "Invalid token address");
governanceToken = _governanceToken;
proposalThreshold = _proposalThreshold;
votingDelay = _votingDelay;
votingPeriod = _votingPeriod;
}
// ============ 提案功能 ============
/**
* @dev 創建提案
* @param targets 目標合約列表
* @param values ETH 數量列表
* @param calldatas 調用數據列表
* @param description 提案描述
*/
function propose(
address[] memory targets,
uint256[] memory values,
bytes[] memory calldatas,
string memory description
) external onlyTokenHolder returns (uint256) {
require(
targets.length == values.length,
"Length mismatch"
);
require(
targets.length == calldatas.length,
"Length mismatch"
);
require(
targets.length > 0,
"No actions"
);
// 檢查提案門檻
// 實際實現需要檢查代幣餘額
uint256 proposalId = proposalCount++;
Proposal storage proposal = proposals[proposalId];
proposal.description = description;
proposal.targets = targets;
proposal.values = values;
proposal.calldatas = calldatas;
proposal.startBlock = block.number + votingDelay;
proposal.endBlock = proposal.startBlock + votingPeriod;
proposal.proposer = msg.sender;
emit ProposalCreated(
proposalId,
msg.sender,
description,
targets,
values,
calldatas,
proposal.startBlock,
proposal.endBlock
);
return proposalId;
}
/**
* @dev 投票
* @param proposalId 提案 ID
* @param support 投票支持：0=反對，1=支持，2=棄權
* @param reason 投票原因（可選）
*/
function castVote(
uint256 proposalId,
uint8 support,
string calldata reason
) external {
Proposal storage proposal = proposals[proposalId];
// 檢查投票狀態
require(
proposal.state() == ProposalState.Active,
"Voting not active"
);
// 檢查是否已投票
require(
!proposal.hasVoted[msg.sender],
"Already voted"
);
// 計算投票權重
// 實際實現需要從治理代幣獲取餘額
uint256 weight = 1; // 簡化版本
// 記錄投票
proposal.hasVoted[msg.sender] = true;
if (support == 1) {
proposal.forVotes += weight;
} else if (support == 0) {
proposal.againstVotes += weight;
} else {
proposal.abstainVotes += weight;
}
emit VoteCast(
msg.sender,
proposalId,
support,
weight,
reason
);
}
/**
* @dev 執行提案
* @param proposalId 提案 ID
*/
function execute(uint256 proposalId) external payable {
Proposal storage proposal = proposals[proposalId];
require(
proposal.state() == ProposalState.Succeeded,
"Proposal not successful"
);
proposal.executed = true;
// 執行提案中的調用
for (uint256 i = 0; i < proposal.targets.length; i++) {
(bool success, ) = proposal.targets[i].call{
value: proposal.values[i]
}(proposal.calldatas[i]);
require(success, "Execution failed");
}
emit ProposalExecuted(proposalId, block.timestamp);
}
// ============ 查詢函數 ============
/**
* @dev 獲取提案狀態
*/
function state(uint256 proposalId) external view returns (ProposalState) {
return proposals[proposalId].state();
}
// ============ 提案狀態計算 ============
function getProposalState(Proposal storage proposal)
internal
view
returns (ProposalState)
{
if (proposal.executed) {
return ProposalState.Executed;
}
if (proposal.canceled) {
return ProposalState.Canceled;
}
if (block.number <= proposal.startBlock) {
return ProposalState.Pending;
}
if (block.number <= proposal.endBlock) {
return ProposalState.Active;
}
// 檢查是否通過
uint256 totalVotes = proposal.forVotes +
proposal.againstVotes +
proposal.abstainVotes;
// 簡化的通過條件
if (proposal.forVotes > proposal.againstVotes &&
proposal.forVotes > totalVotes * QUORUM_THRESHOLD / 1e18) {
return ProposalState.Succeeded;
}
return ProposalState.Defeated;
}
}第五章：安全設計模式
5.1 可升級合約代理模式
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @title 可升級合約代理模式
* @dev 使用代理合約實現可升級功能
*/
// 代理合約
contract Proxy {
bytes32 private constant IMPLEMENTATION_SLOT =
bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1);
bytes32 private constant ADMIN_SLOT =
bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1);
constructor(address _implementation, address _admin) {
require(_implementation != address(0), "Invalid implementation");
_setImplementation(_implementation);
_setAdmin(_admin);
}
// 代理調用
fallback() external payable {
assembly {
let ptr := mload(0x40)
// 獲取 implementation 地址
let implementation := sload(IMPLEMENTATION_SLOT)
// 複製 calldata
calldatacopy(ptr, 0, calldatasize())
// 調用 implementation
let result := delegatecall(
gas(),
implementation,
ptr,
calldatasize(),
0,
0
)
// 複製返回值
returndatacopy(ptr, 0, returndatasize())
// 根據結果返回或回滾
switch result
case 0 { revert(ptr, returndatasize()) }
default { return(ptr, returndatasize()) }
}
}
receive() external payable {}
function _setImplementation(address newImplementation) internal {
assembly {
sstore(IMPLEMENTATION_SLOT, newImplementation)
}
}
function _setAdmin(address newAdmin) internal {
assembly {
sstore(ADMIN_SLOT, newAdmin)
}
}
}
// 實現合約（邏輯合約）
contract ImplementationV1 {
uint256 public value;
event ValueChanged(uint256 newValue);
function setValue(uint256 _value) external {
value = _value;
emit ValueChanged(_value);
}
}
// 升級後的實現合約
contract ImplementationV2 {
uint256 public value;
uint256 public additionalValue;
event ValueChanged(uint256 newValue, uint256 additionalValue);
function setValue(uint256 _value) external {
value = _value;
emit ValueChanged(_value, additionalValue);
}
function setAdditionalValue(uint256 _value) external {
additionalValue = _value;
emit ValueChanged(value, _value);
}
}5.2 速率限制器
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @title 速率限制器
* @dev 防止大規模代幣轉移或智慧合約操作
*/
contract RateLimiter {
// 速率限制配置
struct RateLimitConfig {
uint256 maxAmount; // 最大數量
uint256 timeWindow; // 時間窗口（秒）
}
// 用戶速率限制
mapping(address => RateLimitConfig) public userLimits;
// 用戶歷史記錄
mapping(address => uint256) public userLastUpdate;
mapping(address => uint256) public userSpentAmount;
// 全局限制
uint256 public globalMaxAmount;
uint256 public globalTimeWindow;
uint256 public globalLastUpdate;
uint256 public globalSpentAmount;
// 事件
event RateLimitUpdated(address indexed user, uint256 maxAmount, uint256 timeWindow);
event TransferRateLimited(
address indexed from,
address indexed to,
uint256 amount,
uint256 timestamp
);
/**
* @dev 檢查轉帳是否超過速率限制
*/
function _checkRateLimit(
address from,
uint256 amount,
uint256 maxAmount,
uint256 timeWindow,
mapping(address => uint256) storage lastUpdate,
mapping(address => uint256) storage spentAmount
) internal {
uint256 currentTime = block.timestamp;
// 檢查是否需要重置
if (currentTime - lastUpdate[from] >= timeWindow) {
lastUpdate[from] = currentTime;
spentAmount[from] = 0;
}
// 檢查是否超過限制
require(
spentAmount[from] + amount <= maxAmount,
"Rate limit exceeded"
);
// 更新已使用數量
spentAmount[from] += amount;
}
/**
* @dev 檢查用戶速率限制
*/
function checkUserRateLimit(
address user,
uint256 amount
) external {
RateLimitConfig memory config = userLimits[user];
if (config.maxAmount > 0 && config.timeWindow > 0) {
_checkRateLimit(
user,
amount,
config.maxAmount,
config.timeWindow,
userLastUpdate,
userSpentAmount
);
}
}
/**
* @dev 設置用戶速率限制
*/
function setUserRateLimit(
address user,
uint256 maxAmount,
uint256 timeWindow
) external {
require(maxAmount > 0, "Invalid max amount");
require(timeWindow > 0, "Invalid time window");
userLimits[user] = RateLimitConfig({
maxAmount: maxAmount,
timeWindow: timeWindow
});
emit RateLimitUpdated(user, maxAmount, timeWindow);
}
}結論
本文提供了 Solidity 智慧合約的完整實作範例，涵蓋了 ERC-20 代幣、ERC-721 NFT、借貸協議、AMM 交易所、DAO 治理合約等多種常見合約類型。這些範例展示了智慧合約開發的核心概念和最佳實踐：
- 安全設計：每個合約都包含適當的訪問控制、錯誤處理和事件記錄
- Gas 優化：使用合適的資料結構和演算法減少 Gas 消耗
- 可擴展性：採用模組化設計便於擴展和升級
- 合規性：包含必要的合規檢查和監管報告功能
在實際開發中，工程師應根據具體需求調整這些範例，並進行完整的安全審計後再部署到主網。
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延伸閱讀與來源
- Ethereum.org Developers 官方開發者入口與技術文件
- EIPs 以太坊改進提案
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