**Course Title:** Mastering NestJS: Building Scalable Server-Side Applications **Section Title:** Controllers and Routing **Topic:** Build a basic RESTful API with multiple endpoints using controllers and routing in NestJS.(Lab topic) **Objective:** By the end of this topic, you will be able to create a basic RESTful API with multiple endpoints using controllers and routing in NestJS. You will understand how to define routes, handle HTTP requests and responses, and implement route guards for authentication. **Prerequisites:** * You have completed the previous topics in the Controllers and Routing section. * You have a basic understanding of NestJS and its architecture. * You have a development environment set up with Node.js, TypeScript, and Nest CLI. **Step 1: Create a new NestJS project** Open your terminal and run the following command to create a new NestJS project: ```bash npx @nestjs/cli new nestjs-rest-api ``` This will create a new directory called `nestjs-rest-api` with the basic structure for a NestJS project. **Step 2: Create a new controller** In the `nestjs-rest-api` directory, create a new file called `users.controller.ts`: ```typescript // users.controller.ts import { Controller, Get, Post, Body } from '@nestjs/common'; @Controller('users') export class UsersController { @Get() getAllUsers(): string { return 'Get all users'; } @Post() createUser(@Body() createUserDto: any): string { return 'Create a new user'; } } ``` This controller has two methods: `getAllUsers` and `createUser`. The `@Get()` decorator indicates that the `getAllUsers` method should handle GET requests, while the `@Post()` decorator indicates that the `createUser` method should handle POST requests. **Step 3: Define routes** In the `app.module.ts` file, add the following code to define routes for the `users` controller: ```typescript // app.module.ts import { Module } from '@nestjs/common'; import { AppController } from './app.controller'; import { AppService } from './app.service'; import { UsersModule } from './users/users.module'; @Module({ imports: [UsersModule], controllers: [AppController], providers: [AppService], }) export class AppModule {} ``` In the `users.module.ts` file, add the following code to define the `users` module: ```typescript // users.module.ts import { Module } from '@nestjs/common'; import { UsersController } from './users.controller'; @Module({ controllers: [UsersController], }) export class UsersModule {} ``` **Step 4: Run the application** Run the following command to start the application: ```bash npm run start ``` Open a web browser and navigate to `http://localhost:3000/users to see the `Get all users` endpoint in action. You can also use a tool like Postman to send a POST request to http://localhost:3000/users to see the `Create a new user` endpoint in action. **Conclusion:** In this topic, you learned how to create a basic RESTful API with multiple endpoints using controllers and routing in NestJS. You defined routes, handled HTTP requests and responses, and implemented route guards for authentication. You can now build scalable server-side applications using NestJS. **What's next:** In the next topic, you will learn about dependency injection in NestJS. You will understand how to use dependency injection to manage dependencies between components and services. **Leave a comment or ask for help:** If you have any questions or need help with this topic, please leave a comment below. I'll do my best to assist you. **External resources:** * NestJS documentation: <https://docs.nestjs.com/> * NestJS GitHub repository: <https://github.com/nestjs/nest> * Postman: <https://www.postman.com/> Note: This topic is based on the latest version of NestJS (v9) and may not be compatible with earlier versions.