How to create routes in NestJS

In NestJS, routes are defined within controllers and mapped to HTTP methods like GET, POST, PUT, and DELETE. Here’s an overview of how to create and manage routes in NestJS:

1. Basic Route Structure

Routes in NestJS are defined in controllers using decorators like @Get, @Post, @Put, @Delete, etc.

Example:

typescriptCopy codeimport { Controller, Get, Post, Param, Body } from '@nestjs/common';

@Controller('users') // Base path for all routes in this controller
export class UsersController {
  
  // GET /users
  @Get()
  findAll(): string {
    return 'This will return all users.';
  }

  // GET /users/:id
  @Get(':id')
  findOne(@Param('id') id: string): string {
    return `This will return the user with ID ${id}`;
  }

  // POST /users
  @Post()
  create(@Body() createUserDto: any): string {
    return 'This will create a new user.';
  }
}

---

2. Route Parameters

You can define dynamic route parameters using the @Param() decorator.

Example:

typescriptCopy code@Get(':id')
findOne(@Param('id') id: string): string {
  return `User with ID: ${id}`;
}

---

3. Query Parameters

Use the @Query() decorator to handle query strings.

Example:

typescriptCopy code@Get()
findWithQuery(@Query('role') role: string): string {
  return `This will return users with role: ${role}`;
}

Request example: GET /users?role=admin

---

4. Request Body

The @Body() decorator is used to handle incoming request bodies, often in POST or PUT routes.

Example:

typescriptCopy code@Post()
create(@Body() createUserDto: any): string {
  return `User created with data: ${JSON.stringify(createUserDto)}`;
}

---

5. Route Guards and Middleware

To add authentication or authorization logic, you can use:

• Guards: Protect specific routes.
• Middleware: Apply logic before requests reach controllers.

Example: Adding a guard

typescriptCopy codeimport { Controller, Get, UseGuards } from '@nestjs/common';
import { AuthGuard } from './auth.guard';

@Controller('secure')
export class SecureController {
  
  @Get()
  @UseGuards(AuthGuard)
  findSecureData(): string {
    return 'This is protected data.';
  }
}

---

6. Grouping Routes with Modules

Controllers are registered in modules. For example, in app.module.ts:

typescriptCopy codeimport { Module } from '@nestjs/common';
import { UsersController } from './users/users.controller';

@Module({
  imports: [],
  controllers: [UsersController],
  providers: [],
})
export class AppModule {}

---

7. Prefixing Routes

You can define global route prefixes in main.ts:

Example:

typescriptCopy codeconst app = await NestFactory.create(AppModule);
app.setGlobalPrefix('api');
await app.listen(3000);

Routes will now be prefixed with /api:

• GET /api/users
• POST /api/users

---

8. Handling Sub-Routes

NestJS supports nested controllers for handling sub-routes.

Example:

typescriptCopy code@Controller('users')
export class UsersController {
  @Get('profile')
  getProfile(): string {
    return 'User profile route';
  }

  @Get('settings')
  getSettings(): string {
    return 'User settings route';
  }
}

Routes:

• GET /users/profile
• GET /users/settings

---

9. Custom Route Decorators – Routes in NestJS

You can create custom route decorators for cleaner and reusable code.

Example:

typescriptCopy codeimport { createParamDecorator, ExecutionContext } from '@nestjs/common';

export const User = createParamDecorator(
  (data: unknown, ctx: ExecutionContext) => {
    const request = ctx.switchToHttp().getRequest();
    return request.user;
  },
);

@Get('me')
getProfile(@User() user: any) {
  return user;
}

---

With these examples, you can efficiently create and manage routes in NestJS for a scalable and organized application!

How to create routes in nest js

In NestJS, routes are created using controllers. Controllers handle incoming requests and define endpoints for your application. Below is a step-by-step guide to creating routes in NestJS:

---

1. Install NestJS (if not done already)

Ensure you have NestJS installed. You can create a new project using the Nest CLI:

npm i -g @nestjs/cli
nest new my-nest-app
cd my-nest-app

---

2. Generate a Controller

Use the Nest CLI to generate a controller:

nest generate controller <controller-name>

For example:

nest generate controller users

This creates a users.controller.ts file with a basic structure.

---

3. Define Routes in the Controller

Open the generated controller file (users.controller.ts) and define the routes using decorators like @Get, @Post, @Put, @Delete, etc.

Example:

import { Controller, Get, Post, Param, Body } from '@nestjs/common';

@Controller('users') // Base route
export class UsersController {
  // GET /users
  @Get()
  findAll(): string {
    return 'This action returns all users';
  }

  // GET /users/:id
  @Get(':id')
  findOne(@Param('id') id: string): string {
    return `This action returns user with ID: ${id}`;
  }

  // POST /users
  @Post()
  create(@Body() createUserDto: any): string {
    return 'This action creates a new user';
  }
}

---

4. Use a Module to Register the Controller

Controllers are registered in a module. By default, NestJS generates a AppModule or the module associated with the controller.

In the app.module.ts file:

import { Module } from '@nestjs/common';
import { UsersController } from './users/users.controller';

@Module({
  imports: [],
  controllers: [UsersController],
  providers: [],
})
export class AppModule {}

---

5. Start the Application

Run the application to test the routes:

npm run start

---

6. Test the Routes

You can test the routes using tools like:

• Postman
• cURL
• Browser (for simple GET requests)

For example:

• Navigate to http://localhost:3000/users (GET all users).
• Navigate to http://localhost:3000/users/1 (GET user with ID 1).

---

7. Advanced Features

You can add more advanced features to your routes:

• Middleware: Add logic before requests reach the controller.
• Guards: Handle authentication and authorization.
• Interceptors: Transform or log responses.
• Validation Pipes: Validate request data.

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This is the basic approach to creating and working with routes in NestJS!