AW: [TF-TD] Next web meeting

Hi Michael, hi all,



I was at your presentation yesterday. Thank you for it, it's a solid base to start a discussion. The question I'm about to ask is more of a remark, which you might agree with or not.



You present the TD language as a hypermedia language (slide 10). You also consider classes defined in the TD as resource classes -in the sense of REST resource -  (slide 11). However,  until now, the TD was seen as a single document containing a static declaration of the thing's characteristics. Do you still see the need for it? Or would you rather replace it with a fully-defined hypermedia language?



>From my point of view, the TD language should include the both. More precisely, it should be made of:

*         TD Core, whose early draft can be found in the form of an ontology in the git repository: 'TF-TD/Ontology/w3c-wot-td.owl'. It simply defines concepts like Action, Property, Thing, etc. along with a few constraints.

*         TD Interaction Model, which is tightly related to the work of the AP task force. There is a description of design patterns, written by Johannes in the repo: 'plugfest/interactions.md', and which you complete with the description of associated links/forms.



I guess there is a large consensus in this group that using HATEOAS is the best option for  a WoT interaction model. Therefore, the next question might be: what to use to formally specify these links and forms? You suggested yourself that Hydra was the closest work to what you presented. We could use it as is. To illustrate that, I made a quick example:



This JSON-LD object is equivalent to the "property" links from the /light object  (slide 16):

{

  "@context": {

    "hydra": "http://www.w3.org/ns/hydra/core#<http://www.w3.org/ns/hydra/core>",

    "td": "http://www.w3c.org/wot/td#<http://www.w3c.org/wot/td>"

  },

  "@type": "td:Thing",

  "hydra:property": {

    "@id": "http://www.example.com:80/ledlamp/ColorTemp/currentValue",

    "@type": "hydra:Link",

    "range": "td:Property"

  }

}



This example also raises the following question: when developers model a TD, do they need to model both the core thing characteristics and the interaction model, or defining the former is enough to derive default interactions from it? We could map TD concepts to Hydra concepts (a Thing is a resource, an Action is a resource where one can POST with precise parameters, etc.). With such a mapping, hypermedia could easily be inferred from a TD file. For instance, let's assume /light is already associated with the TD documents 'TF-TD/TD Samples/led.jsonld' on Github, the upper JSON-LD object doesn't bring much once we declared the td:Property "colorTemperature". We simply have to say at the ontology level 'every  td:Property of a td:Thing is attached to the latter by a hydra:property'. I started such a mapping work, see 'TF-TD/Ontology/w3c-wot-td-interaction-model.owl' (will be pushed today).



I'm looking forward to your reaction about this. Criticisms are very welcome.



Best regards,

Victor Charpenay





Von: Anicic, Darko [mailto:darko.anicic@siemens.com]
Gesendet: Dienstag, 15. September 2015 15:55
An: public-wot-ig@w3.org
Betreff: [TF-TD] Next web meeting



Dear TD-TF members,



please find enclosed slides for tomorrow's talk at the TD web conference:



Hypermedia Design for Machine APIs - Web Scale Architecture for the Web of Things

Michael J Koster



For the seconds planned talk the slides have already been sent to the list (see previous mail).



Best wishes,

Darko



Von: Anicic, Darko [mailto:darko.anicic@siemens.com]
Gesendet: Dienstag, 15. September 2015 09:59
An: public-wot-ig@w3.org<mailto:public-wot-ig@w3.org>
Betreff: [TF-TD] Next web meeting



Dear TD-TF members,



please find below the agenda and web meeting details for the TD web conference tomorrow (16th of September 2015 at 14:00 - 15:30 BST / 15:00 - 16:30 CEST / 6:00 - 7:30 PDT / 22:00 - 23:30 JST).



Best wishes

Darko Anicic





Draft agenda:

- We will have two talks:

     1) Michael Koster will present HATEOAS

     2) Frank Reusch will give a talk on: Lemonbeat smart Device Language (LsDL), see attached slides.

- Discussion/Brainstorming/Next steps





Meeting details:

Meeting number: 643 820 889

Audio connection: +1-617-324-0000 US Toll Number, 643 820 889

Meeting password: wotig

Meeting link: https://mit.webex.com/mit/j.php?MTID=ma8aa4594b4fc8a5d7728eb2a586917ce