feat: 班级小助手 阶段1-3（monorepo + 后端 REST/Socket.IO + Web 管理端）

packages/server/src/middleware/error.ts

@@ -0,0 +1,65 @@
+import type { ErrorRequestHandler, RequestHandler } from 'express';
+import { ZodError } from 'zod';
+import type { ApiErrorResponse } from '@classhelper/shared';
+import { ApiError } from '../lib/http.js';
+import { logger } from '../lib/logger.js';
+import { env } from '../config/env.js';
+
+function sendError(
+  res: Parameters<ErrorRequestHandler>[2],
+  status: number,
+  message: string,
+  code: string,
+  details?: unknown,
+): void {
+  const body: ApiErrorResponse = { success: false, data: null, message, code };
+  if (details !== undefined) body.details = details;
+  res.status(status).json(body);
+}
+
+/** 404：未匹配到任何路由 */
+export const notFoundHandler: RequestHandler = (req, res) => {
+  sendError(res, 404, `接口不存在：${req.method} ${req.originalUrl}`, 'NOT_FOUND');
+};
+
+/** 统一错误处理：把 Zod / ApiError / Prisma 错误转换成统一响应体 */
+export const errorHandler: ErrorRequestHandler = (error, req, res, _next) => {
+  if (error instanceof ZodError) {
+    const details = error.issues.map((issue) => ({
+      path: issue.path.join('.'),
+      message: issue.message,
+    }));
+    logger.warn(`参数校验失败：${req.method} ${req.originalUrl}`, details);
+    sendError(res, 422, '请求参数不合法', 'VALIDATION_ERROR', details);
+    return;
+  }
+
+  if (error instanceof ApiError) {
+    if (error.status >= 500) logger.error(error.message, error.details);
+    sendError(res, error.status, error.message, error.code, error.details);
+    return;
+  }
+
+  // Prisma 已知错误码（P2002 唯一约束 / P2025 记录不存在 / P2003 外键约束）
+  const prismaCode = (error as { code?: string }).code;
+  if (prismaCode === 'P2002') {
+    sendError(res, 409, '数据已存在，请检查唯一字段（用户名 / 课程名等）', 'CONFLICT');
+    return;
+  }
+  if (prismaCode === 'P2025') {
+    sendError(res, 404, '目标记录不存在或已被删除', 'NOT_FOUND');
+    return;
+  }
+  if (prismaCode === 'P2003') {
+    sendError(res, 400, '关联数据不存在或仍被引用', 'BAD_REQUEST');
+    return;
+  }
+
+  logger.error(`未处理异常：${req.method} ${req.originalUrl}`, error);
+  sendError(
+    res,
+    500,
+    env.isProduction ? '服务器内部错误' : `服务器内部错误：${(error as Error).message}`,
+    'INTERNAL_ERROR',
+  );
+};