Multiple Channels subscribe not working.

mehtahardikr commented 3 years ago

Trying to subscribe channels in list not working.

 var channelList = [];
 var pubnub;
 Subscription subscription;

 pubnub = PubNub(
       defaultKeyset:
       Keyset(subscribeKey: demo', publishKey: 'demo',));

 channelList.add('test');

       subscription = pubnub.subscribe(channels: {channelList.join(",")} ,  withPresence: true);
       debugPrint('${subscription.channels}');

      Future.delayed(Duration(seconds: 30), () async{
        channelList.add('test2');

        subscription = await pubnub.subscribe(
            channels: {channelList.join(",")} );

        debugPrint('${subscription.channels}');

        subscription?.messages?.listen((message) {
          print(message);
        });

      });

if I subscribe one by one then

await  pubnub.subscribe(channels: {'test'} ,  withPresence: true);
await  pubnub.subscribe(channels: {'test1'} ,  withPresence: true);

then it returns messages which are queued for 'test1' channel , seems to be weired issue.

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• No issues found!

are commented 3 years ago

Hi! Each pubnub.subscribe call returns a new subscription. After you create a subscription you cannot change it, so if you want to add a new channel to the subscription you either need to create a separate subscription, or .cancel() the previous one.

In each subscription you will only receive messages from the channels that were in the original subscription.

Additionally, you shouldn't do channelList.join(','). Instead you should pass in your channelList as such pubnub.subscribe(channels: channelList.toSet(), ...).

Edit: Here is a solution that you can evaluate for your use-case if you need to use multiple subscriptions: https://github.com/pubnub/dart/issues/44#issuecomment-825053295

mehtahardikr commented 3 years ago

@are : okay fine, let me check like this. thank you.

pubnub / dart

Multiple Channels subscribe not working. #56