Re: [WoT IG] Proposals for potential work items of a WoT WG

> On 10 Aug 2015, at 04:51, <kajimoto.kazuo@jp.panasonic.com> <kajimoto.kazuo@jp.panasonic.com> wrote:
> 
> Dear Joerg-san and WoT IG members,
>  
> I strongly agree with Joerg-san’s proposal that listing up items for preparing WG first,
> before WG charter detail discussion.

I have risen to the challenge, see:

        https://www.w3.org/WoT/IG/wiki/Proposals_for_WoT_WG_work_items

>  
> I’m confident we could conclude abstract WoT API in spite of not only wide variety of
> description languages but also wide variety of implementation models such as “Web
> Centric”, “Smartphone Centric”, “Hub Centric” and “Cloud Centric” as described in attached
> PDF file.

Thanks for providing those slides.  All of the cases you depict are supported by the above proposals.

Note that when a web page running in a browser wants to access “things” on a server, the browser and the single origin security policy imposes some restrictions, e.g. the range of protocols is limited to those that browsers expose to web page scripts. Furthermore, the single origin security policy will require the same domain name as for the HTTP server used to download the web page.

In my implementation work, I used NodeJS to create a server that supports both HTTP and WebSockets specifically to address these restrictions. In principle, CORS headers could be used to enable the use of servers with separate domain names.  Something to explore in the future is the potential for using the data channel exposed by WebRTC. This would enable a web page on one browser to access things hosted by a web page on another browser.

There is an open source implementation of NodeJS for Android that makes it easy to implement a web of things hub/server on a smart phone or tablet. NodeJS also works well on high end microcontrollers such as the Raspberry Pi, which makes it easy to experiment with home hubs.

I think we should be careful with how we use the term WoT API.  This could be used for scripting APIs, e.g. as exposed to JavaScript or other scripting languages. It may also be used in an abstract sense to describe a messaging protocol.  I have been careful to limit my use of API in the scripting language API sense, and bindings to protocols for the messaging protocol sense.

Whilst it would be desirable to have the same scripting APIs on different programming languages and IoT platforms, I suspect that IoT platforms will have significant variations in their needs, and as a result, it may be harder to standardise WoT APIs across platforms. It is for this reason that I have not included APIs in the work items in the proposed charter.


Best regards,

—
   Dave Raggett <dsr@w3.org <mailto:dsr@w3.org>>