[Python]WebSocketによる通信

pip install fastapi uvicorn websockets

from fastapi import FastAPI, WebSocket, WebSocketDisconnect

app = FastAPI()
clients = set()

async def broadcast(sender, msg):
    dead = []
    for ws in clients:
        if ws == sender:
            continue
        try:
            await ws.send_text(msg)
        except:
            dead.append(ws)
    for d in dead:
        clients.remove(d)

@app.websocket("/ws")
async def websocket_endpoint(ws: WebSocket):
    await ws.accept()
    clients.add(ws)
    print("client connected")

    try:
        while True:
            msg = await ws.receive_text()
            await broadcast(ws, msg)

    except WebSocketDisconnect:
        clients.remove(ws)
        print("client disconnected")

$ uvicorn python-websocket-server:app --reload
INFO:     Will watch for changes in these directories: ['/home/user/']
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [1164753] using StatReload
INFO:     Started server process [1164755]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     127.0.0.1:55778 - "WebSocket /ws" [accepted]
client connected
INFO:     connection open
INFO:     127.0.0.1:33024 - "WebSocket /ws" [accepted]
client connected
INFO:     connection open
client disconnected
INFO:     connection closed
client disconnected
INFO:     connection closed
INFO:     Shutting down
INFO:     Waiting for application shutdown.
INFO:     Application shutdown complete.
INFO:     Finished server process [1164755]
INFO:     Stopping reloader process [1164753]

import asyncio
import websockets
import sys

URI = "ws://localhost:8000/ws"

async def sender(ws):
    loop = asyncio.get_event_loop()
    while True:
        line = await asyncio.to_thread(sys.stdin.readline)
        if not line:
            break
        await ws.send(line.rstrip())

async def receiver(ws):
    try:
        async for msg in ws:
            print(msg)
    except:
        pass

async def main():
    async with websockets.connect(URI) as ws:
        await asyncio.gather(sender(ws), receiver(ws))

try:
    asyncio.run(main())
except KeyboardInterrupt:
    pass

$ python3 -B python-websocket-client.py 
Hello

$ uvicorn python-websocket-server:app --reload

$ python3 -B python-websocket-client.py 

$ python3 -B python-websocket-client.py 

Hello

Hello