fix: 改进 Vercel serverless 配置和路径处理

- 修复 vercel.json 构建配置
- 使用 path.join 处理文件路径
- 添加更详细的日志输出
- 改进错误处理和回退机制
- 添加 installCommand 确保正确构建

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/index.ts

@@ -4,6 +4,7 @@ import { ValidationPipe } from '@nestjs/common';
 import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
 import * as express from 'express';
 import * as bodyParser from 'body-parser';
+import { join } from 'path';
 
 // 缓存 app 实例，避免每次冷启动都重新创建
 let cachedApp: any;
@@ -13,11 +14,22 @@ async function bootstrap() {
     const expressApp = express();
 
     // 动态导入模块，支持构建后的路径
-    const { AppModule } = await import('../dist/app.module.js');
+    let AppModule;
+    try {
+      // 尝试从 dist 目录加载
+      const distPath = join(process.cwd(), 'dist', 'app.module.js');
+      AppModule = (await import(distPath)).AppModule;
+    } catch (error) {
+      console.error('Failed to load from dist:', error.message);
+      // 回退到 src 目录
+      const srcPath = join(process.cwd(), 'src', 'app.module.ts');
+      AppModule = (await import(srcPath)).AppModule;
+    }
 
     const app = await NestFactory.create(
       AppModule,
       new ExpressAdapter(expressApp),
+      { logger: ['error', 'warn', 'log'] }
     );
 
     // 配置 CORS
@@ -41,8 +53,9 @@ async function bootstrap() {
 
     // 尝试加载全局过滤器和拦截器（如果存在）
     try {
-      const { HttpExceptionFilter } = await import('../dist/common/filters/http-exception.filter.js');
+      const distCommonPath = join(process.cwd(), 'dist', 'common');
-      const { TransformInterceptor } = await import('../dist/common/interceptors/transform.interceptor.js');
+      const { HttpExceptionFilter } = await import(join(distCommonPath, 'filters', 'http-exception.filter.js'));
+      const { TransformInterceptor } = await import(join(distCommonPath, 'interceptors', 'transform.interceptor.js'));
       app.useGlobalFilters(new HttpExceptionFilter());
       app.useGlobalInterceptors(new TransformInterceptor());
     } catch (error) {
@@ -74,6 +87,8 @@ async function bootstrap() {
 
     await app.init();
     cachedApp = expressApp;
+
+    console.log('NestJS app initialized successfully');
   }
   return cachedApp;
 }
@@ -81,13 +96,15 @@ async function bootstrap() {
 // Vercel Serverless handler
 export default async function handler(req: any, res: any) {
   try {
+    console.log(`Request: ${req.method} ${req.url}`);
     const app = await bootstrap();
     app(req, res);
   } catch (error) {
     console.error('Handler error:', error);
     res.status(500).json({
       error: 'Internal Server Error',
-      message: error.message
+      message: error.message,
+      stack: process.env.NODE_ENV === 'development' ? error.stack : undefined
     });
   }
 }

vercel.json

@@ -2,7 +2,7 @@
   "version": 2,
   "builds": [
     {
-      "src": "package.json",
+      "src": "api/index.ts",
       "use": "@vercel/node"
     }
   ],
@@ -11,5 +11,6 @@
       "src": "/(.*)",
       "dest": "/api/index.ts"
     }
-  ]
+  ],
+  "installCommand": "pnpm install && pnpm run build"
 }