start channels (django) support (#190)

* start channels (django) support

* implemented django channels

* version bump and dependencies

Author: jell-o-fishi

Diff for: CHANGELOG.rst

@@ -1,6 +1,10 @@
 Changelog
 ---------
 
+v0.4.19
+=======
+- Added Django Channels transport support for WebSocket communication
+
 v0.4.18
 =======
 - Fixed Stalette/FastAPI implementation and added example using FastAPI server

Diff for: README.md

@@ -18,6 +18,7 @@ You may also install using some **extras**:
 | reactivex       | [ReactiveX](https://reactivex.io/) ([v4](https://pypi.org/project/reactivex/)) integration | [Tutorial](https://rsocket.io/guides/rsocket-py/tutorial/reactivex) |
 | aiohttp         | [aiohttp](https://docs.aiohttp.org/en/stable/) Websocket transport (server/client)         | [Tutorial](https://rsocket.io/guides/rsocket-py/tutorial/websocket) |
 | fastapi         | [fastapi](https://github.com/fastapi/fastapi) Websocket transport (server/client)          |                                                                     |
+| channels        | Websocket transport (server only) using channels (django)                                  |                                                                     |
 | quart           | [Quart](https://pgjones.gitlab.io/quart/) Websocket transport (server only)                |                                                                     |
 | quic            | [QUIC](https://github.com/aiortc/aioquic) transport                                        |                                                                     |
 | websockets      | [Websockets](https://github.com/python-websockets/websockets) transport (server only)      |                                                                     |

Diff for: docs/conf.py

@@ -24,7 +24,7 @@
 author = '[email protected]'
 
 # The full version, including alpha/beta/rc tags
-release = '0.4.18'
+release = '0.4.19'
 
 # -- General configuration ---------------------------------------------------
 

Diff for: examples/django_channels/README.md

@@ -0,0 +1,111 @@
+# RSocket with Django Channels
+
+This example demonstrates how to use RSocket with Django Channels, allowing you to implement RSocket protocol support in your Django applications.
+
+## Overview
+
+Django Channels extends Django to handle WebSockets, and this integration allows you to use the RSocket protocol over those WebSocket connections. This enables:
+
+- Reactive streaming capabilities in Django applications
+- Support for all RSocket interaction models (request-response, fire-and-forget, request-stream, request-channel)
+- Bidirectional communication between client and server
+
+## Requirements
+
+- Django 3.0+
+- Channels 4.0+
+- An ASGI server like Daphne or Uvicorn
+
+## Installation
+
+1. Install Django Channels:
+   ```bash
+   pip install channels
+   ```
+
+2. Install an ASGI server:
+   ```bash
+   pip install daphne
+   ```
+
+3. Configure your Django project to use Channels (see Django Channels documentation)
+
+## Server Setup
+
+1. Create a request handler for RSocket:
+   ```python
+   from rsocket.payload import Payload
+   from rsocket.request_handler import BaseRequestHandler
+
+   class Handler(BaseRequestHandler):
+       async def request_response(self, payload: Payload):
+           return Payload(b'Echo: ' + payload.data)
+   ```
+
+2. Create an RSocket consumer using the factory:
+   ```python
+   from rsocket.transports.channels_transport import rsocket_consumer_factory
+
+   RSocketConsumer = rsocket_consumer_factory(handler_factory=Handler)
+   ```
+
+3. Add the consumer to your routing configuration:
+   ```python
+   from django.urls import path
+   from channels.routing import ProtocolTypeRouter, URLRouter
+
+   application = ProtocolTypeRouter({
+       'websocket': URLRouter([
+           path('rsocket', RSocketConsumer.as_asgi()),
+       ]),
+   })
+   ```
+
+## Client Usage
+
+You can connect to your Django Channels RSocket server using any RSocket client. Here's an example using the Python client:
+
+```python
+import asyncio
+import websockets
+from rsocket.helpers import single_transport_provider
+from rsocket.payload import Payload
+from rsocket.rsocket_client import RSocketClient
+from rsocket.transports.websockets_transport import WebsocketsTransport
+
+async def main():
+    async with websockets.connect('ws://localhost:8000/rsocket') as websocket:
+        transport = WebsocketsTransport()
+        handler_task = asyncio.create_task(transport.handler(websocket))
+        
+        try:
+            async with RSocketClient(single_transport_provider(transport)) as client:
+                response = await client.request_response(Payload(b'Hello'))
+                print(f"Received: {response.data.decode()}")
+        finally:
+            handler_task.cancel()
+            try:
+                await handler_task
+            except asyncio.CancelledError:
+                pass
+
+if __name__ == '__main__':
+    asyncio.run(main())
+```
+
+## Advanced Usage
+
+The Django Channels transport supports all RSocket interaction models:
+
+- **Request-Response**: Simple request with a single response
+- **Fire-and-Forget**: One-way message with no response
+- **Request-Stream**: Request that receives a stream of responses
+- **Request-Channel**: Bi-directional stream of messages
+
+See the server_example.py and client_example.py files for more detailed examples.
+
+## Security Considerations
+
+- Use secure WebSockets (wss://) in production
+- Implement proper authentication and authorization in your Django application
+- Consider using RSocket's authentication and authorization extensions for additional security

Diff for: examples/django_channels/__init__.py

@@ -0,0 +1,78 @@
+"""
+Example of a client connecting to a Django Channels RSocket server.
+
+This example shows how to create a client that connects to a Django Channels
+RSocket server and performs a request-response interaction.
+"""
+
+import asyncio
+import logging
+import ssl
+from typing import Optional
+
+import asyncclick as click
+import websockets
+
+from rsocket.helpers import single_transport_provider
+from rsocket.payload import Payload
+from rsocket.rsocket_client import RSocketClient
+from rsocket.transports.websockets_transport import WebsocketsTransport
+
+
+async def connect_to_django_channels(url: str, ssl_context: Optional[ssl.SSLContext] = None):
+    """
+    Connect to a Django Channels RSocket server using websockets.
+    
+    :param url: WebSocket URL (e.g., 'ws://localhost:8000/rsocket')
+    :param ssl_context: Optional SSL context for secure connections
+    """
+    async with websockets.connect(url, ssl=ssl_context) as websocket:
+        # Create a transport using the websocket connection
+        transport = WebsocketsTransport()
+        
+        # Start the transport handler
+        handler_task = asyncio.create_task(transport.handler(websocket))
+        
+        try:
+            # Create an RSocket client using the transport
+            async with RSocketClient(single_transport_provider(transport)) as client:
+                # Send a request-response
+                payload = Payload(b'Hello from RSocket client')
+                response = await client.request_response(payload)
+                
+                print(f"Received response: {response.data.decode()}")
+                
+                # You can add more interactions here
+                
+        finally:
+            # Clean up the handler task
+            handler_task.cancel()
+            try:
+                await handler_task
+            except asyncio.CancelledError:
+                pass
+
+
+@click.command()
+@click.option('--url', default='ws://localhost:8000/rsocket', help='WebSocket URL')
+@click.option('--secure', is_flag=True, help='Use secure WebSocket (wss://)')
+async def main(url: str, secure: bool):
+    """
+    Connect to a Django Channels RSocket server.
+    """
+    logging.basicConfig(level=logging.INFO)
+    
+    if secure and not url.startswith('wss://'):
+        url = 'wss://' + url.removeprefix('ws://')
+        ssl_context = ssl.create_default_context()
+        # Disable certificate verification for testing
+        ssl_context.check_hostname = False
+        ssl_context.verify_mode = ssl.CERT_NONE
+    else:
+        ssl_context = None
+    
+    await connect_to_django_channels(url, ssl_context)
+
+
+if __name__ == '__main__':
+    main()

Diff for: examples/django_channels/client_example.py

@@ -0,0 +1 @@
+db.sqlite3

Diff for: examples/django_channels/django_rsocket/.gitignore

@@ -0,0 +1,22 @@
+"""
+ASGI config for django_rsocket project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/5.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+from channels.routing import ProtocolTypeRouter, URLRouter
+from .routing import websocket_urlpatterns
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'django_rsocket.settings')
+
+application = ProtocolTypeRouter({
+    "http": get_asgi_application(),
+    "websocket": URLRouter(websocket_urlpatterns),
+})

Diff for: examples/django_channels/django_rsocket/__init__.py

@@ -0,0 +1,28 @@
+import logging
+
+from channels.routing import ProtocolTypeRouter, URLRouter
+from django.urls import path
+
+from rsocket.helpers import create_future
+from rsocket.payload import Payload
+from rsocket.request_handler import BaseRequestHandler
+from rsocket.transports.channels_transport import rsocket_consumer_factory
+
+
+# Define a request handler for RSocket
+class Handler(BaseRequestHandler):
+    async def request_response(self, payload: Payload):
+        logging.info(payload.data)
+
+        return create_future(Payload(b'Echo: ' + payload.data))
+
+
+# Create a consumer using the factory
+RSocketConsumer = rsocket_consumer_factory(handler_factory=Handler)
+
+# Django Channels routing configuration
+application = ProtocolTypeRouter({
+    'websocket': URLRouter([
+        path('rsocket', RSocketConsumer.as_asgi()),
+    ]),
+})

Diff for: examples/django_channels/django_rsocket/django_rsocket/__init__.py

@@ -0,0 +1,6 @@
+from django.urls import path
+from .consumers import RSocketConsumer
+
+websocket_urlpatterns = [
+    path('rsocket', RSocketConsumer.as_asgi()),
+]