chanx 0.13.1

Installation

pip install chanx

For complete documentation, visit chanx docs.

Introduction

Django Channels provides excellent WebSocket support for Django applications, but leaves gaps in authentication, structured messaging, and developer tooling. Chanx fills these gaps with a comprehensive toolkit that makes building WebSocket applications simpler and more maintainable.

Using Generic Type Parameters

AsyncJsonWebsocketConsumer uses three generic type parameters for improved type safety:

class AsyncJsonWebsocketConsumer[IC, Event, M]:
    """
    Typed WebSocket consumer with three generic parameters:

    IC: Incoming message type (required) - Union of BaseMessage subclasses
    Event: Channel event type (optional) - Union of BaseChannelEvent subclasses or None
    M: Model type (optional) - Django model for object-level permissions
    """

You can use these parameters in different combinations:

# Minimal usage - just specify incoming message type
class SimpleConsumer(AsyncJsonWebsocketConsumer[PingMessage]):
    async def receive_message(self, message: PingMessage, **kwargs: Any) -> None:
        # message is properly typed as PingMessage
        ...

# With incoming messages and events
class EventConsumer(AsyncJsonWebsocketConsumer[ChatMessage, ChatEvent]):
    async def receive_message(self, message: ChatMessage, **kwargs: Any) -> None:
        # Handle incoming messages
        ...

    async def receive_event(self, event: ChatEvent) -> None:
        # Handle typed events using pattern matching
        match event:
            case NotifyEvent():
                # Process the notification event
                await self.send_message(ResponseMessage(payload=event.payload))
            case _:
                pass

# With group messaging
class GroupConsumer(AsyncJsonWebsocketConsumer[ChatMessage]):
    async def receive_message(self, message: ChatMessage, **kwargs: Any) -> None:
        # Send typed group messages using send_group_message
        group_msg = MemberMessage(payload={"content": "Hello group!"})
        await self.send_group_message(group_msg)

# Complete example with all generic parameters
class ChatConsumer(AsyncJsonWebsocketConsumer[ChatMessage, ChatEvent, Room]):
    # Room is used for object-level permissions
    queryset = Room.objects.all()

    async def build_groups(self) -> list[str]:
        # self.obj is typed as Room
        return [f"room_{self.obj.id}"]

# No events, with model
class ModelConsumer(AsyncJsonWebsocketConsumer[ChatMessage, None, Room]):
    ...

# With events, no model
class EventOnlyConsumer(AsyncJsonWebsocketConsumer[ChatMessage, ChatEvent]):
    ...

Configuration

Chanx can be configured through the CHANX dictionary in your Django settings. Below is a complete list of available settings with their default values and descriptions:

# settings.py
CHANX = {
    # Message configuration
    'MESSAGE_ACTION_KEY': 'action',  # Key name for action field in messages
    'CAMELIZE': False,  # Whether to camelize/decamelize messages for JavaScript clients

    # Completion messages
    'SEND_COMPLETION': False,  # Whether to send completion message after processing messages

    # Messaging behavior
    'SEND_MESSAGE_IMMEDIATELY': True,  # Whether to yield control after sending messages
    'SEND_AUTHENTICATION_MESSAGE': True,  # Whether to send auth status after connection

    # Logging configuration
    'LOG_RECEIVED_MESSAGE': True,  # Whether to log received messages
    'LOG_SENT_MESSAGE': True,  # Whether to log sent messages
    'LOG_IGNORED_ACTIONS': [],  # Message actions that should not be logged

    # Playground configuration
    'WEBSOCKET_BASE_URL': 'ws://localhost:8000'  # Default WebSocket URL for discovery
}

WebSocket Routing

Chanx provides Django-style routing functions specifically designed for WebSocket applications. These functions work similarly to Django’s URL routing but are optimized for Channels and ASGI applications.

Key principles:

• Use chanx.routing for WebSocket routes in your routing.py files

• Use django.urls for HTTP routes in your urls.py files

• Maintain clear separation between HTTP and WebSocket routing

Available functions:

• path(): Create URL patterns with path converters (e.g., '<int:id>/')

• re_path(): Create URL patterns with regular expressions

• include(): Include routing patterns from other modules

Example routing setup:

# app/routing.py
from chanx.routing import path, re_path
from . import consumers

router = URLRouter([
    path("", consumers.MyConsumer.as_asgi()),
    path("room/<str:room_name>/", consumers.RoomConsumer.as_asgi()),
    re_path(r"^admin/(?P<id>\d+)/$", consumers.AdminConsumer.as_asgi()),
])

# project/routing.py
from chanx.routing import include, path
from channels.routing import URLRouter

router = URLRouter([
    path("ws/", URLRouter([
        path("app/", include("app.routing")),
        path("chat/", include("chat.routing")),
    ])),
])

WebSocket Playground

Add the playground to your URLs and explore your WebSocket endpoints interactively:

urlpatterns = [
    path('playground/', include('chanx.playground.urls')),
]

Visit /playground/websocket/ to test your endpoints without writing JavaScript.

Complete Example Project

For a full production-ready implementation with advanced patterns and deployment configurations, check out the complete example project:

GitHub Repository: chanx-example

This repository demonstrates:

• Production deployment configurations

• Advanced authentication patterns

• Group messaging and channel events

• Comprehensive testing strategies

• Real-world usage patterns

Learn More

• Quick Start Guide - Step-by-step setup instructions

• User Guide - Comprehensive feature documentation

• API Reference - Detailed API documentation

• Examples - Real-world usage examples