graphene-subscriptions: Error: "subscriptions are not allowed"

Guys, I figured it out, I used the examples given in this tests with their schemas and they worked properly. So on my code I’ll modify it a little bit so that it can receive signals.

And also

@johnpaul89 The rest of your code looks fine at first glance. My guess is that it’s an issue with Django signals. Can you verify that your signals are firing properly? Something simple like this is a good test:

# signals.py
def trigger_graphene_subscriptions(sender, **kwargs):
    print('signals are working')
    post_save_subscription(sender, **kwargs)

post_save.connect(trigger_graphene_subscriptions, sender=ChatMessage, dispatch_uid="chat_message_post_save")

If your terminal doesn’t print that, it means your signals aren’t being read. What you do is try calling your app in init.py using your apps config default_app_config = 'subs.apps.SubsConfig'

Thanks @jaydenwindle for the package.

@levinotik I get an error. Could be an issue with graphql-core: https://github.com/graphql-python/graphql-core/issues/149.

{
  "errors": [
    {
      "message": "Subscription must return Async Iterable or Observable. Received: <Promise at 0x2bab7d44108 fulfilled with <rx.core.anonymousobservable.AnonymousObservable object at 0x000002BAB7D44348>>"
    }
  ],
  "data": null
}

Well, I’ll be damned. Works now! Thanks so much for your time on this, really appreciate it!

I don’t understand where is the solution?

Thanks a lot, @jaydenwindle that’s helpful!

Thank you @jaydenwindle, @levinotik I’m happy to state that this was very helpful. I’m recommending graphene-subscriptions to anyone looking to plug subscriptions.

Ok, just passed runserver to our custom manage.sh script and it seems to work! All good now.

I’m not sure, taking a closer look. I first need to fix some issues that will let me run with the regular runserver and not WSGI which you had said won’t work because WS requests need to be processed asynchronously.

Ok, I think I may have found the issue. This is definitely on me for not documenting something this important in the readme 🤦‍♂️.

You’ll need to set up Channel Layers in order for subscriptions to work properly. If you don’t want to set up a Redis in your dev environment, you can set up Channel Layers using an in-memory backend by adding the following to your settings.py file:

CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels.layers.InMemoryChannelLayer"
    }
}

I’m updating the REAME now. Can you give this a try and see if it works for you? I still think you might have a config issue (since there are no websocket connections in the logs), but let’s try this first.

Hey @levinotik! Yes, afaik the default GraphiQL view in Graphene doesn’t support subscriptions out of the box. That’s really neat that you can add subscription support to the default GraphiQL view by passing in a different backend, I didn’t know that!

I usually use GraphQL Playground to test anything subscription-related. Can you test this example in GraphQL Playground to see whether it’s a GraphiQL view issue or a subscriptions implementation issue that’s happening here?

I’ll see if I can reproduce this locally as well. Can you post some more details about your setup (requirements.txt, how you’re triggering the subscription, etc) to help me debug?

I think I actually got past that issue by creating a custom GraphQLCoreBackend

class GraphQLCustomCoreBackend(GraphQLCoreBackend):
    def __init__(self, executor=None):
        # type: (Optional[Any]) -> None
        super().__init__(executor)
        self.execute_params['allow_subscriptions'] = True

and hooking it up in my urls.py as in path('graphql/', csrf_exempt(CustomGraphQLView.as_view(graphiql=True, backend=GraphQLCustomCoreBackend())), name='graphql').

The issue now is that I’m receiving this error:

“message”: “Subscription must return Async Iterable or Observable. Received: <Promise at 0x1097354d0 rejected with AttributeError("‘NoneType’ object has no attribute ‘filter’")>”

My resolve function is defined as:

    def resolve_stage_changed(root, info, id):
        return root.filter(
            lambda event:
            event.operation == UPDATED and
            isinstance(event.instance, Turn) and
            event.instance.pk == int(id)
        ).map(lambda event: event.instance)

Any guidance on this?