Time to take a leadership position on client-side APIs

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