python websocket pub-sub with re-publish/broadcast

Question

I would like to set-up a server that can subscribe to an external stream over a websocket (ws_ext) and then republish that data (after curating) to internal clients connecting to this server over websockets (ws_int).

My approach so far is to set up a fastapi server that can open websockets (ws_int) with internal clients . However, I don't understand how to have a listener embedded in this server that can listen to external stream and then publish to these internal clients in a non blocking way.

Can someone point me to a working example that can help?

Here is what i would like to achieve:

p.s: I HAVE BEEN able to make it work by decoupling broadcaster from subscriber using redis pubsub. So, what i have now setup is a client that listens to external stream, curate and pushes it to redis pubsub. then i have a separate broadcaster that listens to redis pubsub and pushes it out to clients after curating on its websockets. I would still love to combine these two without using redis or some such backend.

Answer 1

if you have all clients connected to an async ws located in the broadcaster then the same time push whatever that's coming asynchronously to broadcaster from external website the process should be unblocking supposedly the update process can have a async stream pipeline to filter results coming from external website for each client in broadcaster as for example to async client for WebSocket it can go by "with async"

async def hello():
    async with websockets.connect(
            'ws://localhost:8765', ssl=ssl_context) as websocket:
        name = input("What's your name? ")

        await websocket.send(name)
        print(f"> {name}")

        greeting = await websocket.recv()
        print(f"< {greeting}")

asyncio.get_event_loop().run_until_complete(hello())