Re: what is the minimal feature set of a wot server?

> On 19 Jun 2015, at 21:37, Hamish Cunningham <hamish@gate.ac.uk> wrote:
> Is there a definition somewhere of what a WoT server does?
> 
> (I've had a brief poke around in https://github.com/w3c/web-of-things-framework <https://github.com/w3c/web-of-things-framework> -- is that
> the best place to look at present?)

See also the slides introducing the framework:

    http://www.w3.org/2015/05/wot-framework.pdf <http://www.w3.org/2015/05/wot-framework.pdf>

In brief, the idea is to define virtual objects (things) as proxies for physical and abstract entities, modelling them in terms of metadata, events, properties and actions.  The protocol bindings define the messages for signalling events, property updates, invoking actions and sending back the corresponding results. No one protocol will fulfil all needs.  Examples of protocols under consideration include HTTP, Web Sockets, CoAP, MQTT, XMPP and AMQP. Each thing has a URI for its model, which is formalised in terms of linked data, and may be expressed using JSON-LD.  

Thing properties can be other things, which provides a basis for discovery analogous to following links in HTML. There are many other ways for discovering things, so we are now starting to work on an abstraction layer that decouples search queries from the underlying mechanisms.

The Web of Things is intrinsically a distributed asynchronous system, and thing implementations can be located as appropriate, e.g. on microcontrollers, smart phones, home hubs, and cloud based server farms. A minimalist implementation would host a single thing and a single protocol binding, e.g. MQTT or CoAP.  Time synchronisation across a group of Thing servers can be used to support tightly coordinated actuation.

Web pages can access things via HTPP and Web Sockets, subject to the single origin policy, and its extension through cross origin resource sharing (CORS).  Security, privacy and resilience are important topics of investigation.

The work is still at an early stage and the details are being worked out as we address the questions thrown up during implementation work.  A W3C Working Group will be launched late this year to standardise the framework in terms of thing descriptions and bindings to a variety of protocols.

Your help in this endeavour is welcomed!

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