Channels for WebSocket support in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Channels layer for WebSocket support.

Django

from channels import [1]

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

Aconsumers

Blayers

Crouting

Dwebsocket

Attempts:

3 left

💡 Hint

Common Mistakes

Importing 'layers' instead of 'routing'

Trying to import 'websocket' directly

Confusing 'consumers' with routing

The routing module is imported from Channels to define WebSocket URL routes.

2fill in blank

medium

Complete the code to define a WebSocket consumer class inheriting from the correct Channels base class.

Django

from channels.generic.websocket import [1]

class ChatConsumer([1]):
    pass

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

AAsyncWebsocketConsumer

BWebsocketHandler

CWebsocketConsumer

DAsyncConsumer

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'WebsocketHandler' which does not exist

Using synchronous 'WebsocketConsumer' when async is preferred

Using 'AsyncConsumer' which is more generic

AsyncWebsocketConsumer is the recommended base class for asynchronous WebSocket consumers in Channels.

3fill in blank

hard

Fix the error in the routing configuration by completing the WebSocket URL pattern.

Django

from django.urls import re_path
from . import consumers

websocket_urlpatterns = [
    re_path(r'ws/chat/(?P<[1]>[^/]+)/$', consumers.ChatConsumer.as_asgi()),
]

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

Aroom_name

Broomname

Croom-name

Droom

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'roomname' without underscore

Using hyphenated 'room-name' which is invalid in regex group names

Using 'room' which may not match consumer code

The URL pattern uses room_name as the named group to capture the chat room identifier.

4fill in blank

hard

Fill both blanks to complete the async method that accepts a WebSocket connection and adds the user to a group.

Django

async def connect(self):
    self.room_group_name = f'chat_[1]'
    await self.channel_layer.[2](
        self.room_group_name,
        self.channel_name
    )
    await self.accept()

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Aroom_name

Bsend

Cgroup_add

Dgroup_send

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'send' instead of 'group_add' for channel layer method

Using 'group_send' which sends messages, not adds channels

Using wrong variable name for room identifier

The room_name variable is used to create the group name string. The group_add method adds the channel to the group.

5fill in blank

hard

Fill all three blanks to complete the async method that receives a message and sends it to the group.

Django

async def receive(self, text_data):
    text_data_json = json.loads(text_data)
    message = text_data_json['message']

    await self.channel_layer.[1](
        self.room_group_name,
        {
            'type': '[2]',
            'message': message
        }
    )

async def chat_message(self, event):
    message = event['message']

    await self.send(text_data=json.dumps([3]))

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

Agroup_send

Bchat_message

C{'message': message}

Dgroup_add

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'group_add' instead of 'group_send'

Mismatching the 'type' string with the handler method name

Sending raw message string instead of a dictionary

The group_send method sends a message to the group. The type specifies the handler method chat_message. The send method sends the JSON message back to the WebSocket client.