Status codes and headers in NestJS - Mini Project: Build & Apply

Status codes and headers

📖 Scenario: You are building a simple NestJS API that responds to client requests with proper HTTP status codes and custom headers. This helps clients understand the result of their requests and receive extra information.

🎯 Goal: Create a NestJS controller with one GET endpoint that returns a JSON message. Set a custom HTTP status code and add a custom header to the response.

📋 What You'll Learn

Create a controller named AppController

Add a GET route handler method named getHello

Set the HTTP status code to 201 (Created) for the response

Add a custom header X-Custom-Header with value NestJS

Return a JSON object with a message property set to 'Hello World'

💡 Why This Matters

🌍 Real World

APIs often need to send specific status codes and headers to inform clients about the result of their requests and provide extra metadata.

💼 Career

Understanding how to control HTTP status codes and headers is essential for backend developers building RESTful APIs with NestJS.

1

Create the controller and GET method

Create a NestJS controller class named AppController. Inside it, add a method named getHello decorated with @Get() that returns an object { message: 'Hello World' }.

NestJS

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

@Controller()
export class AppController {
  // Your code here
}

Need a hint?

Use @Controller() to define the controller and @Get() to define the GET route handler.

2

Add HTTP status code 201

Import @HttpCode from @nestjs/common. Add the decorator @HttpCode(201) above the getHello method to set the HTTP status code to 201.

NestJS

import { Controller, Get, HttpCode } from '@nestjs/common';

@Controller()
export class AppController {
  @Get()
  // Your code here
  getHello() {
    return { message: 'Hello World' };
  }
}

Need a hint?

The @HttpCode() decorator sets the response status code.

3

Inject response object to set headers

Import Res and Response from @nestjs/common and express respectively. Modify the getHello method to accept a parameter res decorated with @Res() and typed as Response. Use res.setHeader('X-Custom-Header', 'NestJS') to add the custom header. Then send the JSON response using res.status(201).json({ message: 'Hello World' }).

NestJS

import { Controller, Get, HttpCode, Res } from '@nestjs/common';
import { Response } from 'express';

@Controller()
export class AppController {
  @Get()
  @HttpCode(201)
  getHello(@Res() res: Response) {
    // Your code here
  }
}

Need a hint?

Use the @Res() decorator to get the response object and set headers before sending the response.

4

Complete the controller with proper imports

Ensure the imports include Controller, Get, HttpCode, and Res from @nestjs/common, and Response from express. The AppController class should have the getHello method as defined with the custom header and status code.

NestJS

import { Controller, Get, HttpCode, Res } from '@nestjs/common';
import { Response } from 'express';

// Verify all code is present and correct
// Your code here

Need a hint?

Check that all imports and method code are correct and complete.