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Re: UPnP service implementing an intent

From: Greg Billock <gbillock@google.com>
Date: Wed, 23 Nov 2011 10:17:16 -0800
Message-ID: <CAAxVY9czxvS49rX6KMzBwK_bWxL77zbfDUqQwJMZOH5KV2qKtg@mail.gmail.com>
To: James Hawkins <jhawkins@chromium.org>
Cc: Jean-Claude Dufourd <jean-claude.dufourd@telecom-paristech.fr>, public-web-intents@w3.org
Web Intents as an API is a way for clients to request particular functions
of generic services and receive replies (or, viewed the other way, for
services to receive requests from arbitrary clients and provide replies).

There's a mechanism in our proposal for web pages to indicate to the
browser that they can service intents, but that is not the limit of what
entities could participate in the ecosystem. It is equally possible for the
browser to provide built-in services or for those services to be registered
by and handled by OS-resident applications.

I don't have a firm grasp on the scope of the use cases for home networking
discovery, but the intents API would be sufficient to, for example, send a
request to a particular piece of attached equipment and get a response.

Example use case:
A web app wanted to play a song; it could prepare an intent payload with
the song and issue a "play" intent.

navigator.startActivity(new Intent("play", "audio/mp3", song));

The browser consults its UPNP directory (I know nothing about how that
works, but presumably the browser could keep track of registered attached
devices and their capabilities.) It finds two devices that know how to play
MP3s and presents the user with a picker. The user chooses to play the song
on one of them, and the song plays.

I'm sure this simple example doesn't capture the full scope of the problem.
Perhaps it shows why there is hope the problems are related, though?

On Wed, Nov 23, 2011 at 9:03 AM, James Hawkins <jhawkins@chromium.org>wrote:

> Can't the UA receive the broadcast of the UPnP service and add it to the
> intent registry?  In general our model has the UA being the broker for
> platform-level interactions with intents.
> James
> On Wed, Nov 23, 2011 at 7:38 AM, Jean-Claude Dufourd <
> jean-claude.dufourd@telecom-paristech.fr> wrote:
>> Dear all,
>> In the Home Network TF of Web and TV IG, we discussed discovery of
>> services, including the discovery of those services offered through
>> existing protocols such as UPnP.
>> I heard at the TPAC that web intents are the way to satisfy the HNTF
>> requirements on discovery.
>> >From reading the emails on this list, I do not see how it is possible to
>> wrap UPnP services as intents.
>> It seems a mediator or proxy would be needed, receiving the initial
>> broadcast of the UPnP service announcing itself, translating that to an
>> intent registration and sending it to the intents broker.
>> If so, then no, web intents do not satisfy the HNTF requirements on
>> discovery, or at least, there is a significant missing part.
>> Best regards
>> JC
>> --
>> JC Dufourd
>> Directeur d'Etudes/Professor
>> Groupe Multimedia/Multimedia Group
>> Traitement du Signal et Images/Signal and Image Processing
>> Telecom ParisTech, 37-39 rue Dareau, 75014 Paris, France
>> Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
Received on Wednesday, 23 November 2011 18:17:49 UTC

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