Django talk: Re: Django Channels 2.0.0 groups

The docs do mention this in a big callout at the top of the Channel Layers page :) http://channels.readthedocs.io/en/latest/topics/channel_layers.html

Andrew

On Fri, Feb 2, 2018 at 8:52 PM, Ahmed Magdy <ahmedmgd715@gmail.com> wrote:

Aha thanks for making it clear, I will read more about redis then. Shouldn't the docs mention that though?

On Saturday, February 3, 2018 at 6:47:47 AM UTC+2, Andrew Godwin wrote:
No, there is no in-memory channel layer any more, only Redis is available at the moment. You must put something into the settings in order to make it function.

Andrew
On Fri, Feb 2, 2018 at 8:42 PM, Ahmed Magdy <ahmed...@gmail.com> wrote:
I thought it uses in memory channel layer by default if it's empty? I didn't try setting a value, because only redis was available in v2.0.0 and I don't like using stuff I don't understand.

On Saturday, February 3, 2018 at 6:08:02 AM UTC+2, Andrew Godwin wrote:
It needs to contain a value to work - what value were you trying that was not empty?

Andrew
On Fri, Feb 2, 2018 at 8:04 PM, Ahmed Magdy <ahmed...@gmail.com> wrote:
I tried not having CHANNEL_LAYERS or setting it to {}
same exception

On Saturday, February 3, 2018 at 3:36:43 AM UTC+2, Andrew Godwin wrote:
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 <ahmed...@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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Re: Django Channels 2.0.0 groups

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