Re: What does getSessions return?

On Thu, Aug 6, 2015 at 5:43 PM, Jonas Sicking <jonas@sicking.cc> wrote:

> Hi All,
>
> It's not clear to me if getSessions returns only sessions that were
> received by a presenting browsing context? Or if it also contains
> sessions that were created by the same page calling start() on a
> PresentationRequest?
>

I believe the intent of the current spec is the latter, but I could see
some utility for including sessions created via start/join as well.


>
> In theory you could imagine an application which opens a page on a TV,
> and then that page on the TV opens another page on a second TV. For
> example in a conferance system where you display slides on one TV, and
> then those slides display a video on a second TV.
>
> Or a video conferance system which connects to a TV to display the
> people you are conferencing with. The TV could then try to connect to
> other TVs in order to distribute the videos of conference members to
> other TVs.
>

Both totally make sense and would be useful to add to our use cases
document [1].   I'll add this to a pending PR.


>
> If I read the spec correctly, the "set of presentations" concept
> contains both incoming and outgoing sessions. Is there a reason for
> that? I'd prefer if it only contained incoming sessions. If there's a
> use case for accessing all outgoing sessions (are there?) we could
> always add separate API for accessing those.
>

The ambiguity stems, in part, from trying to write one spec to define two
different implementations: one for the presenting browsing context, and
another for the controlling/initiating browsing context.

Francois filed [2] to try to structure the spec in a way to make it easier
to keep these concepts distinct.  In the meantime (if we agree with my
interpretation of the spec), we could define two sets of presentations:

- The set of initiated presentations
- The set of running presentations

And limit getSessions() to returning the latter.

m.


> / Jonas
>
>
[1] https://github.com/w3c/presentation-api/blob/gh-pages/uc-req.md
[2] https://github.com/w3c/presentation-api/issues/93