WebSocket events handling in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Flask-SocketIO class.

Flask

from flask_socketio import [1]

Drag options to blanks, or click blank then click option'

AFlaskSocket

BFlaskIO

CSocket

DSocketIO

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'FlaskSocket' instead of 'SocketIO'.

Trying to import from 'flask_socket' instead of 'flask_socketio'.

The SocketIO class is imported from flask_socketio to enable WebSocket support in Flask.

2fill in blank

medium

Complete the code to create a SocketIO instance with the Flask app.

Flask

socketio = [1](app)

Drag options to blanks, or click blank then click option'

ASocket

BSocketIO

CFlaskSocketIO

DFlaskSocket

Attempts:

3 left

💡 Hint

Common Mistakes

Using a class name that does not exist like 'Socket' or 'FlaskSocket'.

Forgetting to pass the Flask app instance.

The SocketIO instance wraps the Flask app to enable WebSocket event handling.

3fill in blank

hard

Fix the error in the event handler decorator to listen for 'message' events.

Flask

@socketio.on('[1]')
def handle_message(msg):
    print('Received:', msg)

Drag options to blanks, or click blank then click option'

Amessage

Bdisconnect

Cconnect

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'connect' or 'disconnect' which are for connection events, not messages.

Using 'send' which is a method, not an event name.

The event name for receiving messages is 'message'. Using this decorator listens for incoming messages.

4fill in blank

hard

Fill both blanks to emit a 'response' event with data back to the client.

Flask

socketio.[1]('[2]', {'data': 'Hello client!'})

Drag options to blanks, or click blank then click option'

Aemit

Bsend

Cresponse

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using send instead of emit for custom events.

Using 'message' as event name instead of 'response'.

Use emit to send a custom event named 'response' with data to the client.

5fill in blank

hard

Fill all three blanks to define a handler for client connection and send a welcome message.

Flask

@socketio.on('[1]')
def [2]():
    socketio.[3]('welcome', {'msg': 'Welcome!'})

Drag options to blanks, or click blank then click option'

Aconnect

Bhandle_connect

Cemit

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'message' instead of 'connect' for the decorator.

Naming the handler function incorrectly or forgetting it.

Using 'send' instead of 'emit' to send the welcome message.

The @socketio.on('connect') decorator listens for client connections. The handler function handle_connect sends a 'welcome' event using emit.