Server-Sent Events alternative in Flask - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a common alternative to Server-Sent Events (SSE) for real-time communication in Flask?

WebSockets are a common alternative to SSE. They allow two-way communication between client and server, unlike SSE which is one-way from server to client.

intermediate

How does WebSocket communication differ from Server-Sent Events?

WebSockets provide full-duplex communication, meaning both client and server can send messages independently. SSE only allows the server to push updates to the client.

beginner

Which Flask extension helps implement WebSockets easily?

Flask-SocketIO is a popular extension that simplifies adding WebSocket support to Flask applications.

intermediate

What is a key benefit of using WebSockets over SSE in a chat application?

WebSockets allow instant two-way messaging, so users can send and receive messages in real time without refreshing or waiting for server pushes.

intermediate

Can WebSockets work over the same HTTP ports as SSE?

Yes, WebSockets start with an HTTP handshake on the same ports (usually 80 or 443) and then upgrade the connection to a persistent socket.

Which of these is a two-way communication protocol suitable as an SSE alternative?

A Long Polling

B HTTP Polling

C WebSockets

D AJAX

WebSockets allow two-way communication, unlike SSE which is one-way from server to client.

Which Flask extension is commonly used to add WebSocket support?

A Flask-SocketIO

B Flask-RESTful

C Flask-WTF

D Flask-Migrate

Flask-SocketIO simplifies WebSocket integration in Flask apps.

What is a limitation of Server-Sent Events compared to WebSockets?

A Only server can send messages

B Only supports text data

C Requires HTTPS

D Does not work in modern browsers

SSE only allows server-to-client messages, no client-to-server communication.

How do WebSockets start their connection?

A Direct TCP connection

B HTTP handshake then upgrade

C UDP broadcast

D FTP session

WebSockets begin with an HTTP handshake and then upgrade to a persistent socket connection.

Which scenario benefits most from WebSockets over SSE?

A Live news feed

B Simple notifications

C Static website

D Interactive chat app

Interactive chat apps need two-way communication, which WebSockets provide.

Explain why WebSockets are often preferred over Server-Sent Events for real-time apps in Flask.

Think about how messages flow between client and server.

Describe how a WebSocket connection is established starting from an HTTP request.

Consider the initial steps before the connection stays open.