req.headers for HTTP headers in Express - Mini Project: Build & Apply

Accessing HTTP Headers with req.headers in Express

📖 Scenario: You are building a simple Express server that needs to read HTTP headers sent by clients. HTTP headers carry important information like user agents or custom tokens.

🎯 Goal: Create an Express server that reads the req.headers object to access HTTP headers and sends back a response showing one specific header value.

📋 What You'll Learn

Create an Express app with a single GET route at '/'

Use req.headers to access the HTTP headers object

Extract the user-agent header from req.headers

Send a response that includes the user-agent header value

💡 Why This Matters

🌍 Real World

Web servers often need to read HTTP headers to understand client details, like browser type or authentication tokens.

💼 Career

Knowing how to access HTTP headers with req.headers is essential for backend developers working with Express to handle requests properly.

1

Set up Express app and import express

Write code to import express and create an Express app instance called app.

Express

const express = require('express');
// Your code here

Need a hint?

Use require('express') to import Express and call it to create app.

2

Create a GET route at '/'

Add a GET route handler on app for path '/' with parameters req and res.

Express

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  // Your code here
});

Need a hint?

Use app.get with path '/' and a callback with req and res.

3

Access the user-agent header from req.headers

Inside the GET route, create a variable called userAgent and set it to req.headers['user-agent'] to get the user agent string.

Express

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  // Your code here
});

Need a hint?

Use bracket notation req.headers['user-agent'] to get the header value.

4

Send the user-agent header value in the response

Use res.send to send a string response that says User Agent: followed by the userAgent variable.

Express

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  const userAgent = req.headers['user-agent'];
  // Your code here
});

Need a hint?

Use template strings with backticks to include userAgent in the response.