refactor: 重构后端鉴权方式

apps/backend/src/auth/guards/auth.guard.ts

@@ -0,0 +1,38 @@
+// auth.guard.ts
+import { Injectable, CanActivate, ExecutionContext, UnauthorizedException } from '@nestjs/common';
+import { Request } from 'express';
+import { UserSessionService } from 'src/user/services/user-session.service';
+import { UserService } from 'src/user/user.service';
+
+@Injectable()
+export class AuthGuard implements CanActivate {
+    constructor(
+        private userService: UserService,
+        private userSessionService: UserSessionService,
+    ) { }
+
+    async canActivate(context: ExecutionContext): Promise<boolean> {
+        const request = context.switchToHttp().getRequest<Request>();
+
+        // 从 Cookie 读取 session
+        const sessionId = request.cookies?.['session'];
+        if (!sessionId) {
+            throw new UnauthorizedException('登陆凭证无效，请重新登陆');
+        }
+
+        // 验证 session
+        const session = await this.userSessionService.getSession(sessionId);
+        if (!session) {
+            throw new UnauthorizedException('登陆凭证无效，请重新登陆');
+        }
+
+        // 附加 user 到 req
+        const user = await this.userService.findOne({ userId: session.userId });
+        if (!user) {
+            throw new UnauthorizedException('用户不存在');
+        }
+
+        (request as any).user = { ...user, sessionId };
+        return true;
+    }
+}

apps/backend/src/auth/guards/optional-auth.guard.ts

@@ -0,0 +1,16 @@
+import { ExecutionContext, Injectable } from "@nestjs/common";
+import { AuthGuard } from "./auth.guard";
+
+@Injectable()
+export class OptionalAuthGuard extends AuthGuard {
+    async canActivate(context: ExecutionContext): Promise<boolean> {
+        try {
+            return await super.canActivate(context);
+        } catch (error) {
+            // 验证失败时，req.user = null，但允许继续
+            const request = context.switchToHttp().getRequest();
+            request.user = null;
+            return true;
+        }
+    }
+}