Application-level middleware in Express - Mini Project: Build & Apply

Building Application-Level Middleware in Express

📖 Scenario: You are creating a simple Express server that logs request details for every incoming request. This helps you monitor what requests your server receives.

🎯 Goal: Build an Express app that uses application-level middleware to log the HTTP method and URL of each request before sending a response.

📋 What You'll Learn

Create an Express app instance

Add application-level middleware that logs request method and URL

Add a route handler for GET requests to '/'

Send a simple text response from the route handler

💡 Why This Matters

🌍 Real World

Logging requests helps developers monitor and debug web servers in real time.

💼 Career

Understanding middleware is essential for backend developers working with Express to build scalable web applications.

1

Create Express app instance

Write code to import Express and create an 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

Add application-level middleware

Add application-level middleware to app using app.use that logs the HTTP method and URL of each request. Use parameters req, res, and next. Call next() after logging.

Express

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

// Add middleware to log method and URL
// Your code here

Need a hint?

Use app.use with a function that logs req.method and req.url, then calls next().

3

Add GET route handler for '/'

Add a GET route handler on app for path '/' that sends the text response 'Hello, world!'. Use parameters req and res.

Express

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

app.use((req, res, next) => {
  console.log(`${req.method} ${req.url}`);
  next();
});

// Add GET route handler for '/' here
// Your code here

Need a hint?

Use app.get with path '/' and send 'Hello, world!' in the response.

4

Start the server on port 3000

Add code to start the Express server by calling app.listen on port 3000. Provide a callback that logs 'Server running on port 3000'.

Express

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

app.use((req, res, next) => {
  console.log(`${req.method} ${req.url}`);
  next();
});

app.get('/', (req, res) => {
  res.send('Hello, world!');
});

// Start server on port 3000
// Your code here

Need a hint?

Use app.listen(3000, () => { console.log(...) }) to start the server.