Notify subscriptions on closed socket

[jordanmarkov]

Hello,

I need to run some cleanup code when a clent unsubscribes or disconnects. Function similar to unsubscribed(root, info, *args, **kwds) for the case when a client disconnects would be perfect. Is this possible?

[prokher]

Dear @jordanmarkov,

GraphqlWsConsumer has on_connect method to handle the connection event. Probably we should add on_disconnect there to handle disconnect, e.g. to cleanup something. What do you think? Will this address your need?

[jordanmarkov]

Hello @prokher ,

Not really. I would need the arguments for the subscription. I came up with some not really good solution, but it works for my use case. The problem is it uses private members:

class GraphQLWsConsumer(channels_graphql_ws.GraphqlWsConsumer):
    # ...

    async def disconnect(self, code):
        self._assert_thread()
        for sid in self._subscriptions:
            subinf = self._subscriptions[sid]
            await self._run_in_worker(subinf.unsubscribed_callback)
        await super().disconnect(code)

    # ...

class MySubscription(channels_graphql_ws.Subscription):
    class Arguments:
        arg1 = graphene.String(required=True)

    @staticmethod
    async def subscribe(_root, _info, arg1):
        # setup

    @staticmethod
    async def unsubscribed(_root, _info, arg1):
        # cleanup

Something along these lines would be perfect, possibly with another callback, but I don't really care in this case if the client has disconnected or unsubscribed.

[matclayton]

We really need this as well, we have some tidy up to do when a client disconnected on a per subscription based, right now we're trying to hack it together using the functions above, but it would be much nicer to be baked into the library.

[btribouillet]

So it is not possible at the moment?

My use case is that I need to set the user as offline for a specific chatroom, therefore accessing the arguments of the subscription.

It would be good to have the on_disconnect in the consumer as well. But for this specific use case, it won't work unless I have access to the subscription payload.

Meanwhile, I implemented the solution from above.

[matclayton]

This is effectively what we've done, incase it helps someone

class GraphQLWsConsumer(channels_graphql_ws.GraphqlWsConsumer):
    async def disconnect(self, code: int) -> None:
        """
        This handles firing off the unsubscribe functions on subscriptions
        when a client is disconnected, e.g. when they close the browser
        See https://github.com/datadvance/DjangoChannelsGraphqlWs/issues/62
        """
        self._assert_thread()

        # Fire of a GQL Stop (and therefore unsubscribe) for any active subscriptions
        # This is necessary as the library doesnt do this by default.
        for sid in self._subscriptions.copy():
            await self._on_gql_stop(sid)

        await super().disconnect(code)