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Re: ldp-ISSUE-11 (Server-managed properties): Do we need to define server-managed properties or do we leave them to applications? [Linked Data Platform core]

From: Raúl García Castro <rgarcia@fi.upm.es>
Date: Wed, 30 Jan 2013 09:17:07 +0100
Message-ID: <5108D703.3090409@fi.upm.es>
To: Sergio Fernández <sergio.fernandez@salzburgresearch.at>
CC: Henry Story <henry.story@bblfish.net>, "Linked Data Platform (LDP) Working Group" <public-ldp-wg@w3.org>
Hi Sergio,

As Arnaud says, the issue is not resolved yet. Since in the last telcos 
there was not time for discussing it, maybe we can try to advance 
discussion here.

The general opinion in the mailing list is that the servers do not to 
restrict any property. Therefore, I propose the following in order to 
close the issue:

.- To remove from 4.4.1 the following statement:
[[
The only recognized exception are the properties dcterms:modified and 
dcterms:creator that are never under client control - BPR servers must 
ignore any values of these properties that are provided by the client.
]]

.- To include in 4.4.1 the following statement:
[[
However, BPR servers MAY ignore server-managed properties.
]]

One example of the need for this second statement is the following: I 
upload a photo to flickr and later I try to update this photo saying 
that the owner is another person. flickr business logic won't allow me 
to do that.

Kind regards,

El 29/01/13 17:40, Sergio Fernández escribió:
> Hi,
>
> I saw this issue at the agenda, at least, in the last to telcos, but I'm
> not sure about its resolution...
>
> If I still could say something, I would vote -1 to have restrictions on
> those common metadata properties, mainly because:
>
> - As Henry said, we should be careful distinguishing between the content
> and the server status. HTTP already defines mechanisms for some of those
> things ("Last-Modified" and so on).
>
> - In case we would still want to define such data at the triple level,
> we must not use properties already in used with completely different
> semantics, which could cause a potential conflict with the actual data
> manage by LDP servers.
>
> Kind regards,
>
>
> On 17/12/12 15:58, Henry Story wrote:
>> I wonder if this does not raise the issue that one should at some
>> point in the spec distinguish what the server says and what the
>> content says. I think HTTP headers is what the server is saying about
>> the content. I think it is clear that the HTTP headers is the space
>> for the server to make statements, such as last modified and who made
>> the edit - as the server can factually know this. The content on the
>> other hand is something said by the content creator. Now the question
>> is then is in true that the following equivalence is true in n3
>>
>>   { {<>  dc:author ?a } = ?doc }<=>  { ?doc dc:author ?a } }
>>
>>
>> On 2 Oct 2012, at 16:14, Linked Data Platform (LDP) Working Group
>> Issue Tracker<sysbot+tracker@w3.org>  wrote:
>>
>>> ldp-ISSUE-11 (Server-managed properties): Do we need to define
>>> server-managed properties or do we leave them to applications?
>>> [Linked Data Platform core]
>>>
>>> http://www.w3.org/2012/ldp/track/issues/11
>>>
>>> Raised by: Raúl García Castro
>>> On product: Linked Data Platform core
>>>
>>> "4.4.1 If HTTP PUT is performed on an existing resource, BPR servers
>>> must replace the entire persistent state of the identified resource
>>> with the entity representation in the body of the request. The only
>>> recognized exception are the properties dcterms:modified and
>>> dcterms:creator that are never under client control - BPR servers
>>> must ignore any values of these properties that are provided by the
>>> client."
>>>
>>> I think that saying that dcterms:modified and dcterms:creator cannot
>>> be modified by clients is an application-specific restriction.
>>>
>>> I would not include it, but if you think that it is relevant, I would
>>> rewrite it in the style of 5.5.2:
>>> "BPR servers MAY ignore server managed properties such as
>>> dcterms:modified and dcterms:creator".
>>>
>>>
>>>
>>>
>>
>> A short message from my sponsors: Vive la France!
>> Social Web Architect
>> http://bblfish.net/
>>
>


-- 

Dr. Raúl García Castro
http://delicias.dia.fi.upm.es/~rgarcia/

Ontology Engineering Group
Departamento de Inteligencia Artificial
Universidad Politécnica de Madrid
Campus de Montegancedo, s/n - Boadilla del Monte - 28660 Madrid
Phone: +34 91 336 36 70 - Fax: +34 91 352 48 19
Received on Wednesday, 30 January 2013 08:17:32 UTC

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