[occi-wg] OCCI Core/Rendering feedback

[Jean Parpaillon]

Dear Augusto,

Sorry for not being clearer, but this discussion has just begin last
week at plugfest, and I've sent an email trying to summarize, with a
link to my presentation. So let's try to explain my proposals.

Unfortunately, there is no perfect format. JSON format is more compact,
but some important features are missing in order to use it for a full
specification. Utilities (parsers, validators and such) are important
for both formats, a little bit less for JSON but growing. IMO, JSON
rendering must be defined for its wide use in web applications and some
NoSQL storage (Riak...).
Nevertheless, XML/XSD has the following advantages for formal specs:
- comments included: both formal (appinfo) and informal (annotation)
- string typing: 44 base types + extensions/restrictions.

About the completness of schemas, I've been asked several times this
question, so I think a little bit of clarification is needed:
1/ entities must be validated against their category description: we can
use schemas for that, ie each category is described with a schema. In
that case, resource validation can be really fast to implement, but
there is still no formal way of describing categories (XML schema should
be restricted for that),
2/ category description should be validated against a grammar. This
category description, then must provide the implementation enough
information to validate entities: actually OCCI grammar (for text/occi)
is formal but can not embed a lot of semantic about attribute types,
attribute multiplicity and such.

The goal of my XML representation is to fullfill need of 2/. I make the
assumption it is more important to have formal OCCI representation for
extensions, and write a little bit of code to achieve 2/ rather than
having 1/ done by existing tools (XML validators) but not being able to
achieve 2/.

Regards,
Jean

Le 23/09/2013 16:59, Augusto Ciuffoletti a écrit :
> I'm not following this group from the very beginning, and I do not
> remember a discussion about XML as a rendering option. 

> Maybe Andy or
> Thijs have a record about this. JSON appears as more compact wrt XML,
> but probably XML has a richer set of utilities and is overall more
> established: any other relevant difference? There is an ongoing effort
> on a JSON rendering.
> 
> I think that schemas are unable to capture certain semantic aspects of
> OCCI specs, so their application, while useful, is not sufficient.
> Certainly the availability of libraries for navigating complex/deep
> structures is relevant.


-- 
Jean Parpaillon
Open Source Consultant
Phone: +33 6 30 10 92 86
im: jean.parpaillon at gmail.com
skype: jean.parpaillon
linkedin: http://www.linkedin.com/in/jeanparpaillon/en
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