I'm not quite sure why you seem to be using an AsyncConsumer outside of the
context of the Channels routing framework?
Anyway, it sounds like from what you're describing that your listen()
method is blocking, which makes sense, as it connects to an external
websocket and listens on it for messages forever. Not sure why the crashing
Channels websocket takes down the client one, but maybe they are both made
to crash by some third, external, force?
Andrew
On Sun, Jun 17, 2018 at 11:33 AM Nathan Bluvol <nathan.blu...@gmail.com>
wrote:
> I am using Django 2.0.5, Python 3.6.2, Django Channels 2.1.1, aiohttp
> 3.1.3.
>
> Background:
> I am connecting to an external websocket, asynchronously, using aiohttp
> within a background channels worker. Once triggered, the socket connection
> stays alive, listening/streaming, and sends incoming messages to a consumer
> through a group_send. The consumer receives it at the appropriate handler,
> however, after some time, it appears that the channels websocket dies and
> the handler can no longer be found - I get 'No handler for message
> type....' even though it has been working successfully until that point.
> Second issue is that 'await t1' seems to block in the background. I route
> the 'toggle' to backgroundUpdater.py.
>
> *consumers.py*:
>
> from channels.generic.websocket import AsyncWebsocketConsumer
> import json
>
>
> class MyConsumer(AsyncWebsocketConsumer):
>
> async def connect(self):
> await self.channel_layer.group_add('myGroup', self.channel_name)
> await self.accept()
>
> async def disconnect(self, closeCode):
> await self.channel_layer.group_discard('myGroup',
> self.channel_name)
>
> async def receive(self, text_data):
> eventData = json.loads(text_data)
> print(eventData)
> if eventData['myToggle'] == 'on':
> await self.channel_layer.send('toggle',{"type":
> "openConnection"})
> elif eventData['myToggle'] == 'off':
> await self.channel_layer.send('toggle',{"type":
> "closeConnection"})
>
> async def backgroundWorkerUpdate(self, data):
> await self.send(text_data=json.dumps(data['updateTime']))
>
> *backgroundUpdater.py*:
>
> from channels.consumer import AsyncConsumer
> from channels.layers import get_channel_layer
> import asyncio
> import aiohttp
> import json
> from dashboard.models import Info
> import datetime
>
>
> class backgroundConsumer(AsyncConsumer):
> turnOnListener = True
> channelLayer = get_channel_layer()
> loadComplete = False
>
> async def listen(self):
> infoList = Info.objects.filter(active=True)
> subInfoList = []
> for i in infoList:
> subInfoList.append('info'+str(t))\
> self.loadComplete = False
> async with aiohttp.ClientSession() as session:
> async with session.ws_connect('...streamingsiteURL.../
> socket.io/?EIO=3&transport=websocket', ssl=False) as ws:
> await ws.send_str(str(subInfoList))
> async for msg in ws:
> if msg.type == aiohttp.WSMsgType.TEXT:
> if msg.data.startswith('2'):
> await ws.send_str('3')
> else:
> await self.parseListenData(msg)
>
> async def parseListenData(self, msgContent):
> # handles data in here, including a call to datetime
>
> updateMsg = {'type': 'backgroundWorkerUpdate',
> 'updateTime': str(updateTime),
> }
> print('built update msg and now sending to group')
> await self.channelLayer.group_send('myGroup', updateMsg)
>
> async def openConnection(self, event):
> if(self.turnOnListener):
> await self.channelLayer.group_add(
> 'myGroup',
> self.channel_name,
> )
> self.turnOnListener = False
> loop = asyncio.get_event_loop()
> t1 = loop.create_task(self.listen())
> await t1
> print('awaiting t1') # THIS NEVER PRINTS UNTIL THE WEBSOCKET
> IN consumers.py CRASHES
> else:
> print('already turned on listener')
>
> async def closeConnection(self, event):
> print('in close connection') # CANNOT SEEM TO TRIGGER THIS ONCE
> await t1 is called above...
> if(not self.turnOnListener):
> print('turn it off')
>
> *Questions*:
> 1. Why is does this work for some time until the websocket in consumers.py
> crashes? I am assuming it has crashed because of the missing handler (i.e.
> 'No handler...' error).
> 2. Why is the 'await t1' call blocking? When I try to send 'await
> self.channel_layer.send('toggleMarket',{"type": "closeConnection"})', it
> sends, but nothing seems to be received?
>
> I am have been trying to get this to run in different ways, however, I
> cannot seem to resolve these two issues. Any help/suggestions would be
> greatly appreciated.
>
> Thanks!
>
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