websocket_sync_mqtt.py

#!/usr/bin/env python

# WS server example that synchronizes state across clients

import asyncio
import json
import logging
import websockets
from asyncio_mqtt import Client, MqttError

logging.basicConfig()

logger = logging.getLogger(__name__)

STATE = {"value": 0}

USERS = set()

## --------------- MQTT 
async def mqtt_wait():
    while True:
        try:
            logger.info("Connecting to MQTT")
            async with Client("192.168.0.101", username="emqx", password="xxxxx", client_id="Python3") as client:
            # async with Client("192.168.0.101") as client:
                logger.info("Connection to MQTT open")
                async with client.unfiltered_messages() as messages:
                    await client.subscribe('m5cp2/fromDevice')
                    async for message in messages:
                        logger.info("Message %s %s", message.topic, message.payload.decode())
                        message = str(message.payload.decode())
                        await asyncio.wait([user.send(message) for user in USERS])
                # await asyncio.sleep(2)
        except MqttError as e:
            logger.error("Connection to MQTT closed: " + str(e))
        except Exception:
            logger.exception("Connection to MQTT closed")
        await asyncio.sleep(3)

## --------------- WebSocket
def state_event():
    return json.dumps({"type": "state", **STATE})


def users_event():
    return json.dumps({"type": "users", "count": len(USERS)})


async def notify_state():
    if USERS:  # asyncio.wait doesn't accept an empty list
        message = state_event()
        await asyncio.wait([user.send(message) for user in USERS])


async def notify_users():
    if USERS:  # asyncio.wait doesn't accept an empty list
        message = users_event()
        await asyncio.wait([user.send(message) for user in USERS])


async def register(websocket):
    USERS.add(websocket)
    await notify_users()


async def unregister(websocket):
    USERS.remove(websocket)
    await notify_users()

async def counter(websocket, path):
    # register(websocket) sends user_event() to websocket
    await register(websocket)
    try:
        await websocket.send(state_event())
        async for message in websocket:
            data = json.loads(message)
            if data["action"] == "minus":
                STATE["value"] -= 1
                await notify_state()
            elif data["action"] == "plus":
                STATE["value"] += 1
                await notify_state()
            else:
                logging.error("unsupported event: {}", data)
    finally:
        await unregister(websocket)

async def websocket_wait():
    start_server = websockets.serve(counter, "localhost", 6789)
    asyncio.get_event_loop().run_until_complete(start_server)
    asyncio.get_event_loop().run_forever()

def main():
    # logging.basicConfig(level=logging.DEBUG,
    #                    format="%(asctime)s %(levelname)s %(message)s",
    #                   datefmt="%Y-%m-%d %H:%M:%S")
    asyncio.run(asyncio.wait([mqtt_wait(), websocket_wait()]))

main()