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AW: [TF-TD] proposal for JSON format, its application to OCF, and mapping to RDF

From: Peintner, Daniel <daniel.peintner.ext@siemens.com>
Date: Mon, 5 Dec 2016 14:59:58 +0000
To: Dave Raggett <dsr@w3.org>, Public Web of Things IG <public-wot-ig@w3.org>
Message-ID: <D94F68A44EB1954A91DE4AE9659C5A980FF880EB@DEFTHW99EH1MSX.ww902.siemens.net>
Hi Dave, all,

While I understand the desire to convince Web developers and  I acknowledge your work and your background I do not fully agree with your conclusions.

Yes, the format should be easy to understand. Yes, it would be good to have it as concise as possible. Yes, JSON might be a good choice also.

Having said that, we should also take into account the tools that have been built around a given technology and the actual standing/dissemination it has.

JSON-LD seems to be a good solution (tradeoff?)
* it uses JSON format
* it supports RDF (for those who really like/need it)
* there are many tools around it
* ...

Inventing a new JSON format might be more concise BUT does not have any tool ready. Nor is it proved like a standard that has been worked  on for years.

Moreover, I doubt that people gonna write thing description by hand. There will be tools built on top of JSON-LD. For a new format there is no such support.
Hence, conciseness for plain-text thing descriptions might not be an issue (efficiency for restricted devices is another argument but is better solved differently).

Do these arguments make sense?


-- Daniel

Von: Dave Raggett [dsr@w3.org]
Gesendet: Freitag, 2. Dezember 2016 15:52
An: Public Web of Things IG
Betreff: [TF-TD] proposal for JSON format, its application to OCF, and mapping to RDF

I have been working on extending my earlier proposal for a JSON format for thing descriptions and its mapping to RDF. This is intended to be easy for Web developers to understand and also easy to transform to RDF given the appropriate context definitions. It is similar to JSON-LD, and uses @context to bind names to URIs. The obvious question is likely to be why not use JSON-LD?  The answer is that JSON-LD was designed to support RDF in its generality, and as such is more verbose than a JSON format designed for the purpose of describing the object model for things. We want to win over Web developers, so a concise easy to understand format is key.

I have two demo’s you can access from your web browser:

The first provides a wide range of example thing descriptions that are chosen to cover the full range of features for the object models for things, including properties, actions, events and metadata, as well as compound properties, enumerations, unions, streams and things as first class types.


I would like to show demo’s of the streaming use cases in next Wednesday’s main IG teleconference, and lead a discussion around the representation of things in RDF and what we need to do to show its utility for open markets of services.

The second one provides thing descriptions for the complete set of resources as defined in OCF’s OIC 1.1 specification as obtained from https://openconnectivity.org/resources/specifications

You can browse the sixty or so resources and their mapping to RDF:


I am now working on exploring how to generate RAML from the thing descriptions as a way of ensuring that the thing descriptions include the minimum set of metadata needed for accessing OCF based devices. After that I would like to develop an OCF library for my NodeJS hub and demonstrate its interoperability with iotiviity, which is the open source client and server for OCF, see:


Anyone interested in helping with this?

   Dave Raggett <dsr@w3.org<mailto:dsr@w3.org>>
Received on Monday, 5 December 2016 15:00:49 UTC

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