nestjs

NestJS middleware example

Uses createApiLoggerMiddleware to log all API requests and responses to MongoDB. Middleware is applied with app.use() in main.ts. Alternatively, you can use NestModule and MiddlewareConsumer (see below).

Run

From the repo root, build the main package and the example:

npm run build
cd example/nestjs
npm install
npm run build
npm start

Or run with ts-node (from example/nestjs):

npm install
npm run start:ts

With env vars:

MONGO_URI=mongodb://localhost:27017 PORT=3001 npm start

Try

• GET http://localhost:3001/health
• GET http://localhost:3001/api/users
• POST http://localhost:3001/api/login with body { "email": "user@example.com", "password": "secret" } (password is masked in logs)

Logs are written to the api_logger_example.nestjs_logs collection.

Alternative: apply via NestModule

Instead of app.use(createApiLoggerMiddleware(...)) in main.ts, you can apply the middleware in AppModule with MiddlewareConsumer:

// app.module.ts
import { Module, NestModule, MiddlewareConsumer } from '@nestjs/common';
import { AppController } from './app.controller';
import { createApiLoggerMiddleware } from 'api-logger-mongodb';

@Module({
  imports: [],
  controllers: [AppController],
})
export class AppModule implements NestModule {
  configure(consumer: MiddlewareConsumer) {
    consumer
      .apply(createApiLoggerMiddleware({
        mongoUri: process.env.MONGO_URI || 'mongodb://localhost:27017',
        databaseName: 'api_logger_example',
        collectionName: 'nestjs_logs',
        maskFields: ['password', 'token'],
        logResponseBody: true,
        logRequestBody: true,
        getUserInfo: (req: any) => {
          const user = req.user;
          return user ? { id: user.id, email: user.email, role: user.role } : undefined;
        },
      }))
      .forRoutes('*'); // or .forRoutes('api/*') to limit to certain routes
  }
}

Then remove the app.use(createApiLoggerMiddleware(...)) call from main.ts. This approach is useful when you want route-specific logging or to keep middleware configuration in the module.