Setting up WebSocket server in Express - Quick Revision & Summary

Recall & Review

beginner

What is a WebSocket server?

A WebSocket server allows real-time, two-way communication between a client and server over a single, long-lived connection.

beginner

Which Node.js package is commonly used to add WebSocket support to an Express server?

The 'ws' package is commonly used to add WebSocket support to an Express server.

intermediate

How do you create a WebSocket server that works alongside an Express app?

You create an HTTP server from the Express app, then attach the WebSocket server to that HTTP server.

beginner

What event do you listen for to handle new WebSocket connections?

You listen for the 'connection' event on the WebSocket server to handle new client connections.

intermediate

Why is it important to handle errors and close events on WebSocket connections?

Handling errors and close events helps keep the server stable and frees resources when clients disconnect.

Which method creates an HTTP server from an Express app to use with WebSocket?

A ws.createServer(app)

B express.createServer()

C http.createServer(app)

D app.listenWebSocket()

You use Node's http.createServer(app) to create an HTTP server from the Express app.

Which event do you listen to on a WebSocket server to accept new clients?

A connect

B connection

C open

D start

The 'connection' event fires when a new client connects to the WebSocket server.

What package do you install to add WebSocket support in an Express app?

A ws

B websocket-express

C express-ws

D socket.io

The 'ws' package is a popular lightweight WebSocket library for Node.js.

How do you send a message to a connected WebSocket client?

A client.send('message')

B client.emit('message')

C client.write('message')

D client.push('message')

You use the send() method on the WebSocket client to send data.

Why should you handle the 'close' event on a WebSocket connection?

A To restart the server

B To block the client

C To send a welcome message

D To free resources and clean up

Handling 'close' lets you clean up resources when a client disconnects.

Explain the steps to set up a WebSocket server alongside an Express app.

Think about how Express and WebSocket share the same HTTP server.

Describe why WebSocket is useful compared to regular HTTP requests.

Imagine chatting live versus sending letters.