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Re: Web Intents - Scenario: TV System (part 6)

From: Dave Raggett <dsr@w3.org>
Date: Thu, 08 Dec 2011 01:07:57 +0000
Message-ID: <4EE00DED.7030704@w3.org>
To: Greg Billock <gbillock@google.com>
CC: WebIntents <public-web-intents@w3.org>
On 07/12/11 19:12, Greg Billock wrote:
> Use cases, in my mind, are more like "play this video stream on this
> particular TV" and "grab this local content off my media server to
> upload" and "mute that amplifier." That is, they are particular
> "launches" of actions that can be bound by the UA to a potentially
> very complicated interaction going on behind the scenes. That is, even
> if we decide exactly how Web Intents will work to surface those use
> cases to web content, there will still be a great deal of work and
> thinking to do in figuring out how UAs ought to discover and interact
> with HN gear at the local network level.
> If the Web Intents API is being suggested as being applied more
> broadly -- that is, something that wouldn't be anchored to web content
> -- that's something I really haven't considered. I think we should
> focus on applications to the web ecosystem, and that broadening like
> this won't be fruitful. If it turns out that there are clever ways for
> the UA to take advantage of the work to provide functionality to
> non-web-content apps or whatever, that's fine, but I think our primary
> responsibility ought to be to web content developers and users.
> -Greg

Before we cut back the scope of web intents in that way, I think it is 
worth taking a look at what value web intents offers to users and 
developers. An intent can be considered as a kind of action that the app 
wants to perform on behalf of the user.  The set of such actions is open 
and a matter for agreement between app developers and intent providers.  
When it comes to selecting a particular provider, e.g. a particular TV, 
this is a matter for the UA together with an means for the UA to support 
3rd party extensions.  Having bound the intent to a provider, there may 
be further ways to establish what the particular binding can do, and how 
you communicate with it.  There are many ways in which this could be 
realized, and I would suggest it lies beyond the scope of the core web 
intents spec.  One technique is a queryInterface method where the app 
tries to cast the object returned by the web Intent binding to a named 
interface. Another approach is to provide a rich description in some 
format (e.g. XML, JSON or RDF).  This can be specified separately for 
given intents.

Another issue is the extent that the intent is associated with a 
persistent context. A simple example is to remember the user's choice of 
binding for a given intent. However, the context could be much richer, 
and deal with the detailed choices a user makes when exploiting an 
intent through a given binding, e.g. for controlling a sophisticated 
home entertainment system.  This is something that a given binding would 
handle via means to persist state including user preferences. It needn't 
effect the core web intents specification.

I would like to see a way for users to be able to name particular 
devices/instances of services, and it may be worth exposing these names 
in a way that apps can use when requesting a particular intent, e.g. the 
names I use for my various TVs. This would simplify the end user 
experience when different bindings are chosen in different contexts.

Actions for web content could be quite complicated too, and the same 
model applies.

In summary, the services provided by a given intent binding and the 
description of those services is important, but should be specified 
separately from the core web intents spec, and will vary according to 
the intent. We may want to consider ways for apps to pass additional 
context when requesting a particular intent based upon end-user supplied 
information, but this  can be done in a simple way, e.g. as a string 
that the UA or 3rd party extension interprets for a given intent.

p.s. Philipp Hoschka has asked me to add some info about discovery and 
web intents to the DAP WG page, including a brief description of the 
aims, where to look for more details (e.g. this list) and the expected 
roadmap. I will look to you guys for help with that.

Dave Raggett<dsr@w3.org>  http://www.w3.org/People/Raggett
Received on Thursday, 8 December 2011 01:08:22 UTC

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