W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > January 2006

secondary resources

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Mon, 30 Jan 2006 15:25:39 +0000
Message-ID: <43DE2FF3.9060203@hpl.hp.com>
To: "'public-rdf-in-xhtml task force'" <public-rdf-in-xhtml-tf@w3.org>
CC: Pat Hayes <phayes@ihmc.us>


Trying to create words that capture what might be a winnable position on 
secondary resources.

===========

Problem statement:
   Short form: who is Norman Walsh?
(Or what is http://norman.walsh.name/knows/who#norman-walsh ?)


   A URI such as
     http://norman.walsh.name/knows/who
   may have multiple representations including RDF/XML and HTML

   By the TAG resolution of http-range-14, we know that
    http://norman.walsh.name/knows/who
   itself identifies an information resource.

   Reading the RDF/XML representation returned, we learn that
http://norman.walsh.name/knows/who#norman-walsh
   is a Male Person:

[[
<rdf:Description 
rdf:about="http://norman.walsh.name/knows/who#norman-walsh">
       <rdf:type rdf:resource="http://nwalsh.com/rdf/contacts#Contact"/>
       <rdf:type rdf:resource="http://nwalsh.com/rdf/genealogy#Male"/>
       <rdf:type rdf:resource="http://xmlns.com/foaf/0.1/Person"/>
]]

   In the HTML version the same fragment is used for this part of the 
document:

[[
<div class="name"><a name="norman-walsh" id="norman-walsh"></a>Norman 
Walsh&#160;<a href="http://norman.walsh.name/foaf"><img 
src="/graphics/foafTiny.gif" alt="(foaf)" border="0" /></a></div>
]]


Thus the URI
http://norman.walsh.name/knows/who#norman-walsh
when the URL http://norman.walsh.name/knows/who is returned as HTML 
directs the client to a section of an HTML document.

Given these two facts, what is the nature of the secondary resource 
identified by
http://norman.walsh.name/knows/who#norman-walsh


Problem resolution:

The Web does not provide a mechanism for returning a representation of 
secondary resources analagous to the GET request to return 
representations of primary resources.

Rather, the mechanisms, mediated by mime type, that return 
representations concerning secondary resources, return a representation 
that is most appropriate *for that mime type*.

Hence, when the secondary resource is a non-information resource, but 
the primary resource is an HTML document, the normal behaviour is that 
the representation concerning  the secondary resource is a section of 
the HTML document, that relates in some way to the secondary resource. 
However, the nature of that relationship is unspecified. In particular, 
information resources such as those identified by 
http://www.w3.org/People/Connolly/
and
http://www.w3.org/People/Berners-Lee/card
can have secondary resources such as
http://www.w3.org/People/Connolly/#me
and
http://www.w3.org/People/Berners-Lee/card#i
that are non-information resources; and that if the primary resources 
have an HTML representation, it is permitted by Web architecture to also 
provide a section of the HTML document, labelled with a name or id, that 
relates in some unspecified way to the non-information secondary 
resources identified by the URIs with fragments.

==========

(Note Tim and Dan have been more careful over this than Norm.
http://www.w3.org/People/Berners-Lee/card
does not have an HTML representation
http://www.w3.org/People/Connolly/
as an html representation, but no name or id of "me")

How's that?

Jeremy
Received on Monday, 30 January 2006 15:28:27 UTC

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