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Re: Time to take a leadership position on client-side APIs

From: José Manuel Cantera Fonseca <jmcf@tid.es>
Date: Thu, 07 Feb 2008 10:59:18 +0100
To: Dave Raggett <dsr@w3.org>
Cc: public-ddwg@w3.org, Ubiquitous Web Applications Working Group WG <public-uwa@w3.org>
Message-id: <47AAD676.4000107@tid.es>

Hi Dave,

I would distinguish between two kinds of client APIs:

a) Client APIs for the delivery context
b) Client APIs for controlling all the elements of the device (phone 
calls, camera, players, etc)

a) is theoretically covered by the DCCI but I think we need to make the 
delivery context APIs universal and not distinguish between the Client 
and the Server APIs. That's the position I outlined in my Delivery 
Context Universal Interfaces manifesto [1]. Also I think that Javascript 
developers are seeking for simpler interfaces than the DCCI ... and also 
implementors :), I think. The initial work on the advanced API maed in 
the DDWG can serve as a seed for this universal interfaces for the DC

b) is indeed a hot topic these days and for the future. I think it 
involves several standards organizations and alliances, potentially 
(Open AJax Alliance, W3C, OMA, 3GPP, OMTP ...). I've seen many people 
talking about the standardization of this kind of APIs but not real work 
has started yet. So I think we need to start with something, perhaps a 
workshop to raise the needed level of awareness and attract more people 
to the UWA group

Best Regards


Dave Raggett escribió:
> There is huge potential for mobile web applications that can access 
> device capabilities from client-side scripts. There has been a lot of 
> work on J2ME APIs, but we lack standards for exposing local device 
> capabilities to applications running in web browsers. The time has 
> surely come for W3C to bring interested parties together to work on 
> fixing this as a matter of priority.
> Properties like location, with privacy and associated legal issues, 
> will clearly be more complicated to deal with, as we will need to 
> address the security and trust models involved. But other properties 
> like battery level, signal strength, light and vibration control, 
> should be much easier to progress.
> The Device Description WG is defining APIs for access to properties of 
> classes of devices, and the OMA is defining a protocol and server-side 
> API for access to dynamic properties (DPE) that will enable servers to 
> dynamically adapt media streams to match device orientation and 
> bandwidth. The UWA WG has recently moved DCCI to CR and published the 
> first draft WD for an ontology for the delivery context, where the 
> ontology is decoupled from the APIs that it models. DCCI is a 
> client-side framework, but doesn’t itself define any properties. With 
> a little work, DCCI could be used for:
>     * dynamic content adaptation on client
>     * checking battery level, signal strength
>     * controlling the display brightness
>     * turning the phone’s vibrator on and off
>     * checking screen orientation and size
>     * checking available free memory
> The following will need work on trust models and could be part of a 
> second wave:
>     * implementing location-based services
>     * interface to on-phone applications (PIM)
>       including calendar and contacts
>     * allowing web page scripts to initiate phone calls
> It seems timely for the W3C Mobile Web Initiative to create a roadmap 
> for building concensus on client-side access to device capabilities. 
> This seems like something W3C should be taking a leadership position 
> on given the opportunities for third party developers to stimulate 
> mobile data traffic if we succeed in standardizing the APIs. Without 
> such action there is a risk of fragmentation as multiple APIs appear 
> and developers have to choose between them.
> What's the best way to bring together the relevant stake holders? For 
> instance, browser vendors, device vendors, network operators and 
> application developers?
>  Dave Raggett <dsr@w3.org> http://www.w3.org/People/Raggett
Received on Thursday, 7 February 2008 09:58:25 UTC

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