PubNub multiplexing issue

Question

I'm trying to switch from custom WebSockets to PubNub. In my app I need user to subscribe to multiple channels at once so I thought multiplexing is the way to go. The issue is, when I want to subscribe more than 4 channels at once I'm getting endless stream of CORS errors. Subscribing one by one channel with delays in between are making no difference. I have "Stream Controller" extension enabled.

your CORS errors have nothing to do with multiplexing or not. The remote endpoint is refusing the request - you need to configure it to allow cross-origin requests. — Brian Driscoll
Possible duplicate of Cant publish via PUBNUB. Origin is not allowed by Access-Control-Allow-Origin — Brian Driscoll
Providing origin makes no difference. It seems like in current version it's default option and I can publish just fine as long as there are 4 or less channels subscribed. — Paweł Wszoła
did you set the origin in the init? origin: 'pubsub.pubnub.com' - perhaps you can send your source code to PubNub support. — Craig Conover
I discovered what an issue was. State is too big, it has user details including photo thumbnail. The size of it is ~6000 characters. It's still far away from 32kb and I read nothing about different limitations for it and it happened when I subscribed to at least 5 channels. Is there some behind the scene logic that multiplies size of state per amount of channels? 5*~6000 is close to the 32k limit. — Paweł Wszoła

Craig Conover Craig Conover · Accepted Answer · 2016-01-09T18:31:49

PubNub Presence User State Data

https://www.pubnub.com/docs/web-javascript/presence

When you subscribe to multiple channels and provide state, for example:

pubnub.subscribe({
   channel: "ch1,ch2,ch3",
   message: function(message) {
       console.log('message', message);
   },
   state: {
     age: 67,
     username: '[email protected]',
     full: 'Robert Plant',
     country: 'UK',
     latlong: '51.5072° N, 0.1275° W'
     profile_pic: 'http://somewebsite.com/images/rplant.png'
}});

...the state is added to each channel for that user. Each channel has it’s own state per user. Above, each of the three channels is initialized with the same state data, but when you set state, for example:

pubnub.state({
   channel: 'ch2',
   uuid: 'rplant',
   state: {'full_name' : 'Bobby Plant'},
   callback: function(m){console.log(JSON.stringify(m))}
 });

... you can specify a single channel (or multiple channels) and the user by their UUID that you set for them when you initialized PubNub with PUBNUB.int.

As for state size limits, there is the 32KB message limit for publishing message and this is true for presence events, too, since they are just published message on the presence channel.

But in general, you should keep state to a minimum. It is not meant for large amounts of data. And files (images) should be stored on a distributed file system and the URL passed around via PubNub.

PubNub multiplexing issue

2 Answers

PubNub Presence User State Data