[occi-wg] OCCI Categories and Types

[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.

>> 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.

>> - 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?

regards, Ralf