Is it possible to use channel to proxy to another upstream server?

[variable]

I want to use Django to do permission checking and then establish a websocket proxy to an upstream server, is it possible?

[carltongibson]

Hi. I would suspect so yes. You'd need an async websocket client, and then feed the messages to/from that back out from your consumer.

I'm afraid there's nothing built-in to do that as you, but it would be interesting to see what you come up with.

[jtremesay-sereema]

Because I needed to proxify a Jupyter Notebook trough a Django app, here my solution

imoprt asyncio
from channels.generic.websocket import AsyncWebsocketConsumer
from websockets import client as ws_client

class AsyncWebsocketProxyConsumer(AsyncWebsocketConsumer):
    async def websocket_connect(self, message):
        self.upstream = await ws_client.connect("ws://localhost:8888/bla/bla/bla")

        asyncio.create_task(self.receive_upstream())

        await super().accept(subprotocol)

    async def disconnect(self, code):
        await self.upstream.close()

        return await super().disconnect(code)

    async def receive(self, text_data=None, bytes_data=None):
        await self.upstream.send(text_data)

    async def receive_upstream(self):
        async for message in self.upstream:
            await self.send(message)

Disclaimer: I have no idea of what I’m doing, but it’s work on my prod 🤷

[carltongibson]

I saw Simon Willison released an asgi-proxy-lib:

https://github.com/simonw/asgi-proxy-lib

There's an open ticket for WebSocket support:

simonw/asgi-proxy-lib#3

[jtremesay-sereema]

oh, nice. Thx !

[bmiakoun]

@jtremesay-sereema what is subprotocol for? it's not defined

[bmiakoun]

this worked for me https://gist.github.com/brianglass/e3184341afe63ed348144753ee62dce5