WebSocket protocol concept in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the WebSocket protocol?

WebSocket is a communication protocol that allows a two-way, full-duplex connection between a client and a server over a single, long-lived TCP connection.

beginner

How does WebSocket differ from HTTP?

Unlike HTTP, which is request-response and short-lived, WebSocket keeps the connection open, allowing real-time, continuous data exchange without repeated handshakes.

intermediate

What is the initial step to establish a WebSocket connection?

The client sends an HTTP upgrade request to the server asking to switch the protocol from HTTP to WebSocket, called the handshake.

beginner

What does 'full-duplex' mean in WebSocket communication?

Full-duplex means both client and server can send and receive messages independently at the same time without waiting for the other side.

beginner

Why is WebSocket useful for real-time applications?

Because it keeps the connection open and allows instant two-way data flow, WebSocket is great for chat apps, live updates, games, and other apps needing fast interaction.

What protocol does WebSocket start with before switching?

A FTP

B TCP

C SMTP

D HTTP

WebSocket begins with an HTTP handshake to upgrade the connection to WebSocket.

Which feature best describes WebSocket communication?

A Request-response only

B Full-duplex

C One-way streaming

D Stateless

WebSocket supports full-duplex communication, meaning both sides can send data simultaneously.

What happens after the WebSocket handshake is successful?

A A persistent connection is established

B Client sends HTTP requests repeatedly

C Connection closes immediately

D Server sends a file download

After handshake, a persistent, open connection allows continuous data exchange.

Which is NOT a typical use case for WebSocket?

A Static website hosting

B Real-time gaming

C Live chat applications

D Stock price updates

Static websites do not require real-time two-way communication, so WebSocket is unnecessary.

What does the WebSocket protocol use to keep the connection alive?

A Repeated HTTP requests

B Multiple UDP packets

C A single TCP connection

D Email notifications

WebSocket uses a single TCP connection kept open for continuous communication.

Explain how a WebSocket connection is established and why it is different from a normal HTTP connection.

Think about the initial request and what changes after the handshake.

Describe real-life scenarios where WebSocket is a better choice than HTTP and why.

Consider apps that need instant updates without refreshing.