Re: Django Channels 2.0.0 groups

Do you have a CHANNEL_LAYERS setting in your settings file? If so, what is it set to?

Andrew

On Fri, Feb 2, 2018 at 5:17 PM, Ahmed Magdy <ahmedmgd715@gmail.com> wrote:

That's what I did after reading the documentation here's how my channels files look like

# settings.py

# ...

ASGI_APPLICATION = 'djangoChannels.routing.application'

# ...

# routing.py

from django.conf.urls import url

from channels.routing import ProtocolTypeRouter, URLRouter

from channels.auth import AuthMiddlewareStack

from .consumers import ChatConsumer

application = ProtocolTypeRouter({

   # Empty for now (http->django views is added by default)

   'websocket': AuthMiddlewareStack(

       URLRouter([

           url('^sessions/$', ChatConsumer)

       ])

   )

})

# consumers.py

from asgiref.sync import AsyncToSync

from channels.generic.websocket import WebsocketConsumer

class ChatConsumer(WebsocketConsumer):

    def connect(self):

       AsyncToSync(self.channel_layer.group_add)("chat", self.channel_name)

    def disconnect(self):

       AsyncToSync(self.channel_layer.group_discard)("chat", self.channel_name)

After connecting with JS websocket to

ws://127.0.0.1:8000/sessions/

Raises an exception

Performing system checks...

System check identified no issues (0 silenced).
February 03, 2018 - 03:14:29
Django version 2.0.2, using settings 'djangoChannels.settings'
Starting ASGI/Channels development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.
2018-02-03 03:14:29,799 - INFO - server - HTTP/2 support not enabled (install the http2 and tls Twisted extras)
2018-02-03 03:14:29,800 - INFO - server - Listening on endpoint tcp:port=8000:interface=127.0.0.1
[2018/02/03 03:14:32] WebSocket HANDSHAKING /sessions/ [127.0.0.1:8631]
ERROR:root:Exception inside application: 'NoneType' object has no attribute 'group_add'
  File "c:\python35\Lib\asyncio\tasks.py", line 241, in _step
    result = coro.throw(exc)
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\channels\consumer.py", line 53, in __call__
    await await_many_dispatch([receive], self.dispatch)
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\channels\utils.py", line 48, in await_many_dispatch
    await dispatch(result)
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\asgiref\sync.py", line 84, in inner
    return await async_func(*args, **kwargs)
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\asgiref\sync.py", line 67, in __call__
    return await asyncio.wait_for(future, timeout=None)
  File "c:\python35\Lib\asyncio\tasks.py", line 367, in wait_for
    return (yield from fut)
  File "c:\python35\Lib\asyncio\futures.py", line 358, in __iter__
    yield self  # This tells Task to wait for completion.
  File "c:\python35\Lib\asyncio\tasks.py", line 290, in _wakeup
    future.result()
  File "c:\python35\Lib\asyncio\futures.py", line 274, in result
    raise self._exception
  File "c:\python35\Lib\concurrent\futures\thread.py", line 55, in run
    result = self.fn(*self.args, **self.kwargs)
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\asgiref\sync.py", line 76, in thread_handler
    raise e
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\asgiref\sync.py", line 74, in thread_handler
    self.func(*args, **kwargs)
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\channels\consumer.py", line 93, in dispatch
    handler(message)
  File "D:\Programming\DjangoWebsite\HUWebsite\lib\site-packages\channels\generic\websocket.py", line 19, in websocket_connect
    self.connect()
  File "D:\Programming\DjangoWebsite\HUWebsite\husite\djangoChannels\djangoChannels\consumers.py", line 8, in connect
    AsyncToSync(self.channel_layer.group_add)("chat", self.channel_name)
  'NoneType' object has no attribute 'group_add'
[2018/02/03 03:14:32] WebSocket DISCONNECT /sessions/ [127.0.0.1:8631]

On Friday, February 2, 2018 at 7:37:36 PM UTC+2, Andrew Godwin wrote:

Hi Ahmed,

In the new release channel layers are optional - if you don't configure them they will indeed come through as None. The settings format changed slightly too - you can read more here: http://channels.readthedocs.io/en/latest/topics/channel_layers.html

Andrew

On Fri, Feb 2, 2018 at 3:31 AM, Ahmed Magdy <ahmed...@gmail.com> wrote:

I'm relatively new to channels and was using Channels v1.x.x groups easily, but after v2.0.0 update and reading the documentation

# This example uses WebSocket consumer, which is synchronous, and so
# needs the async channel layer functions to be converted.
from asgiref.sync import AsyncToSync

class ChatConsumer(WebsocketConsumer):

    def connect(self):
        AsyncToSync(self.channel_layer.group_add)("chat", self.channel_name)

    def disconnect(self):
        AsyncToSync(self.channel_layer.group_discard)("chat", self.channel_name)

Enter code here...

channel_layer, channel_name are always NoneType and exception occurs.

Is that because I didn't configure channel layers? But in the old version I also used the in memory type and Groups were working well.

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