Why authentication matters in Express - See It in Action

Why authentication matters

📖 Scenario: You are building a simple Express server for a small online store. You want to protect a special route that shows sensitive user information. To do this, you will add a basic authentication check.

🎯 Goal: Build an Express server with a protected route /profile that only allows access if a correct password is provided in the request headers.

📋 What You'll Learn

Create an Express app variable called app

Set a password variable called correctPassword with the value secret123

Add a middleware function called checkAuth that checks if the request header password matches correctPassword

Use the checkAuth middleware on the /profile route to protect it

💡 Why This Matters

🌍 Real World

Authentication is essential to protect user data and private routes in web applications. This project shows a simple way to check credentials before allowing access.

💼 Career

Understanding middleware and authentication in Express is a key skill for backend web development jobs.

1

Set up Express app

Create a variable called express by requiring the 'express' module. Then create a variable called app by calling express().

Express

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

Need a hint?

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

2

Add password variable

Create a variable called correctPassword and set it to the string 'secret123'.

Express

const express = require('express');
const app = express();
const correctPassword = 'secret123';
// Your code here

Need a hint?

Just create a simple string variable with the password.

3

Create authentication middleware

Write a middleware function called checkAuth that takes req, res, and next as parameters. Inside it, check if req.headers.password equals correctPassword. If yes, call next(). Otherwise, respond with status 401 and message 'Unauthorized'.

Express

const express = require('express');
const app = express();
const correctPassword = 'secret123';

function checkAuth(req, res, next) {
  // Your code here
}

Need a hint?

Middleware functions have three parameters and must call next() to continue.

4

Protect the /profile route

Add a GET route /profile to app that uses the checkAuth middleware. The route handler should send the text 'User profile data'.

Express

const express = require('express');
const app = express();
const correctPassword = 'secret123';

function checkAuth(req, res, next) {
  if (req.headers.password === correctPassword) {
    next();
  } else {
    res.status(401).send('Unauthorized');
  }
}

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

Need a hint?

Use app.get with the middleware as the second argument, then the handler.