[occi-wg] OCCI Categories and Types

[Alexander Papaspyrou]

Am 13.08.2010 um 14:34 schrieb Ralf Nyren:

> Alexander,
> 
> On Fri, 13 Aug 2010 13:36:56 +0200, Alexander Papaspyrou <alexander.papaspyrou at tu-dortmund.de> wrote:
> 
>>> com.example.<category_term>.<attr_name>
>> 
>> I don't recall that this ever has been discussed, but it certainly is a very good idea.
> 
> The old (svn r164) docbook spec said:
> "Attributes defined by this standard reside at the root but anyone can define a new attribute by allocating a unique namespace based on their reversed Internet domain (e.g. “com.example.attribute”).
> 
> I think such a namespace policy for attributes would be useful for the examples in the spec and related documents as well. An example is much easier to understand if the contents is well defined.

Agreed. This was just a quick and dirty thing. As soon as things merge into the "real" pages (core, infra or http), we have to take care of that.

>>> I do not quite understand the various Content-type headers used in the
>>> examples. Are they of any significance to the definition/use of categories?
>> 
>> No. They are just supposed to make it easier to spot the type within the core model. So, the MIME types would be something like
>> 
>> application/occi-resource (for the Resource class from core)
>> application/occi-link (for the Link class from core)
>> ... (whatever else is defined as a class in core)
>> 
>> That way, you don't have to analyze the details of a REST resource, but just look at the MIME type delivered by the OCCI container.
> 
> If just for the purpose of the example I can somewhat agree. Otherwise I would say the Content-type header only reflect the body and not what kind of information you happen to have in the header.

Well, we will have to discuss this. I think that it would be good to use the content type for indicating what kind of type from the core model is currently shown; on the other hand, you are right: the MIME type indicates the content of the HTTP request/response.

>>> - In Link header: rel="category http://prov.com/occi#action"
>>>  Is the format rel="category XXX" something new as well?
>> 
>> Yes. We tried to stick as much as possible to the IETF nottingham Link draft [1], not adding any additional vendor-specific extensions.
> 
> Hmm... reading the RFC-to-be version (from August 2010) I do not find "category" to be a registered relation type. Defined in some other document?

No, but the "rel" item allows the registration of new terms ("category") in a defined manner.

-- 
Alexander Papaspyrou
alexander.papaspyrou at tu-dortmund.de

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