Record listens should return the amount of subscribers interested in the record

[Lalem001]

Given the ds-demo-provider, generator will never stop generating after first subscription.

Stepping through the logic:

• Server and provider are started
• Client connects and subscribes to FX/* record
• onSubscription is called
  • isSubscribed is true
  • fx-data-provider subscribes to FX/* record
  • There are now two subscribers!
• Client disconnects.
• One subscriber (fx-data-provider) remains, onSubscription is not called.

I was hoping to have on-demand providers in my current project.
Any suggestions on how to resolve this issue?

[yasserf]

The ds-demo dependencies are out of date. Will look at it in the next hour and keep you updated.

[yasserf]

Hey! Right so you were totally correct. This is actually a design issue I'll discuss with the rest of the core team tomorrow.

We might need to have a different kind of record which is a silent requester so that is doesn't let deepstream know it has the the record. I think that would probably be quite a bit of work tho so will sleep over a solution.

This works great for events so far since they are stateless, but I can see this happening often with records.

Thanks for raising!

[yasserf]

So we have decided on the following as an API change

record.listen( '/bob/', function( recordName, numberOfSubscribers ) {
} );

This way if numberOfSubscribers === 1 and your already providing it you would know to stop.
This is also the least invasive in terms of APIs.

Thoughts?

[Lalem001]

That is a reasonable solution.

Will the function be called per subscription? What happens when transitioning from 1 to 2 subscribers? 1 to 0?

[yasserf]

Should be called everytime a match occur. Will try implementing today and let you know!

[Lalem001]

Any updates on this issue?

[yasserf]

Not yet, it will be in our next release but we are currently focusing on getting a couple more tutorials out on how to use deepstream with different front-end libraries.

[Lalem001]

Not to derail the original topic, but I am very interested to see these tutorials. Have any links?

[yasserf]

They are still a work in progress. Currently polymer elements and a react mixin. Should be issues on website repo you can follow!

[yasserf]

We need to think of a better way to indicate if a record is subscribed to or not than providing numbers.