feat: add utils, error handler and auth middleware

server/middleware/auth.js

@@ -0,0 +1,29 @@
+const jwt = require('jsonwebtoken');
+const { AppError } = require('./errorHandler');
+
+const JWT_SECRET = process.env.JWT_SECRET || 'accountbook_secret_key_2024';
+
+function authenticate(req, res, next) {
+  const token = req.headers.authorization?.split(' ')[1];
+  if (!token) {
+    throw new AppError('请先登录', 401, 'UNAUTHORIZED');
+  }
+
+  try {
+    const decoded = jwt.verify(token, JWT_SECRET);
+    req.userId = decoded.userId;
+    next();
+  } catch (err) {
+    throw new AppError('登录已过期', 401, 'TOKEN_EXPIRED');
+  }
+}
+
+function generateToken(userId) {
+  return jwt.sign({ userId }, JWT_SECRET, { expiresIn: '7d' });
+}
+
+module.exports = {
+  authenticate,
+  generateToken,
+  JWT_SECRET,
+};

server/middleware/errorHandler.js

@@ -0,0 +1,62 @@
+class AppError extends Error {
+  constructor(message, statusCode = 500, code = 'INTERNAL_ERROR') {
+    super(message);
+    this.statusCode = statusCode;
+    this.code = code;
+    this.isOperational = true;
+    Error.captureStackTrace(this, this.constructor);
+  }
+}
+
+function errorHandler(err, req, res, next) {
+  console.error({
+    message: err.message,
+    stack: err.stack,
+    url: req.url,
+    method: req.method,
+    userId: req.userId,
+  });
+
+  if (err instanceof AppError && err.isOperational) {
+    return res.status(err.statusCode).json({
+      error: err.message,
+      code: err.code,
+    });
+  }
+
+  // 数据库唯一性冲突
+  if (err.code === 'SQLITE_CONSTRAINT_UNIQUE') {
+    return res.status(400).json({
+      error: '数据已存在',
+      code: 'DUPLICATE_ENTRY',
+    });
+  }
+
+  // 其他数据库错误
+  if (err.code && err.code.startsWith('SQLITE_')) {
+    return res.status(500).json({
+      error: '数据库错误',
+      code: 'DATABASE_ERROR',
+    });
+  }
+
+  // 默认错误响应
+  res.status(500).json({
+    error: process.env.NODE_ENV === 'production'
+      ? '服务器内部错误'
+      : err.message,
+    code: 'INTERNAL_ERROR',
+  });
+}
+
+function asyncHandler(fn) {
+  return (req, res, next) => {
+    Promise.resolve(fn(req, res, next)).catch(next);
+  };
+}
+
+module.exports = {
+  AppError,
+  errorHandler,
+  asyncHandler,
+};