Re: [discovery] Adding CORS to NSD API - proposal and issues

On Tue, Oct 8, 2013 at 11:30 PM, <Cathy.Chan@nokia.com> wrote:

> > So say device type X is made of services A,B and C:
> >
> > if I make a search and only get A and B, should I assume that C is not
> > present or not CORS enabled or what?
>
> Neither. You should assume that the device is crippled and make your web
> app work with only A and B (e.g. you can stream media to it but would not
> be able to control the volume), or move on to the next device.
>

well I may not know if device X supports service C at all (e.g. is
optional). anyway maybe you are right, it probably doesn't really matter
from an app perspective (the app is not going to fix it anyway)


> exposing/enabling just a pieace of some devices may not make sense.
>
> Actually in some cases, it does. There are certain UPnP service types that
> are not tied to specific device types. Such services can be used
> independently of all other services on the same device. One example is the
> LowPowerDevice service type (yes, it's a service that has the word "device"
> in its name) that allows one to monitor the power state of the parent
> device. For this reason, I've always been of the opinion that searches by
> both device type and service type should be supported.
>
>
OK, you convinced me.

But still, being able to explicitly exclude services UNLESS they are tied
to some device may be a good thing to have, especially because the user is
asked to approve it.

E.g. if the same service is supported both by a device that it makes sense
for my app (say a TV) and for one that doesn't (say a fridge), I may want
to avoid the browser asking the user "this apps want to get access to your
fridge" when I already know I'm not going to do anything with it. The user
may also be confused and ask himself why this music webapp wants to access
my fridge, and walk away.

In short: I agree that search by service should stay, but we should also
add as a complement the ability to specify "I want all services associated
with a device of type X". This way the user is only asked to authorize
things that the app may be able to use. The result could still be a list of
services (so no new Objects required)


 /g