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Re: ConNegging on Description Pages (was RE: Southampton Pub data as linked open data)

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Wed, 30 Jul 2008 09:17:53 -0400
Message-ID: <48906A01.4020502@openlinksw.com>
To: Tom Heath <Tom.Heath@talis.com>
CC: John Goodwin <John.Goodwin@ordnancesurvey.co.uk>, public-lod@w3.org, semantic-web@w3.org

Tom Heath wrote:
> Hi Kingsley,
>
> If I've understood you correctly, you're suggesting that the HTML
> document about a pub should 303 to the RDF/XML document about the pub if
> RDF/XML is requested, and vice versa. (please correct me if I've
> misunderstood)
>
> Is conneging on description pages desirable? i.e. if I request
> http://revyu.com/people/tom/about/rdf
> in my regular browser (e.g. vanilla Firefox), should I be redirected to
> http://revyu.com/people/tom/about/html ?
>
> I don't think so, for the simple reason that I might be a developer
> wishing to study/debug the RDF.
>
> Thoughts?
>   
Tom,

Two things:

1. Re. Southampton pubs, the issue is resolved re. our RDF Browser, it 
came down to a combination of cache and URL encoding
2. Re. Content Negotiation, if the data publisher has access rights on 
the Web Server, I see no reason why Content Negotiation can't be used to 
provide a clear response that factors in explicit representation requests

I my world view, all resources are equal (information or non-informaton 
variants) on the Web re. URI utility, so when requests are made that are 
explicit about desired representation, and you are in a position to 
administer the request target Web Server, use content negotiation to 
honor the precision of the user agent's request.

If I go to a restaurant (in Robot mode i.e. nuance challenged) and ask 
for a glass of water, and the waiter says: OK, and then deliver me a 
glass of ice cubes, what am I to do? I don't see any harm in the waiter 
saying: Sorry, I don't have any water, but I could offer you some ice cubes.


Kingsley 


> Tom.
>
> P.S. Of course <link .../> tags in the HTML header and foaf:page triples
> in the RDF are highly desirable, this question is just about conneg on
> URIs of Info Resources.
>
>
>   
>> -----Original Message-----
>> From: public-lod-request@w3.org 
>> [mailto:public-lod-request@w3.org] On Behalf Of Kingsley Idehen
>> Sent: 28 July 2008 16:47
>> To: John Goodwin
>> Cc: public-lod@w3.org; semantic-web@w3.org
>> Subject: Re: Southampton Pub data as linked open data
>>     
>   
>   
>> John,
>>
>> I am getting:
>>
>> curl -I -H "Accept: application/rdf+xml" 
>> http://www.johngoodwin.me.uk/pubs/description/pub1
>> HTTP/1.1 200 OK
>> Date: Mon, 28 Jul 2008 15:25:49 GMT
>> Server: Apache/2.2.8 (Unix) mod_ssl/2.2.8 OpenSSL/0.9.7a
>> mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635
>> Last-Modified: Sun, 27 Jul 2008 15:52:16 GMT
>> ETag: "1a0322-6ba4-453036415cc00"
>> Accept-Ranges: bytes
>> Content-Length: 27556
>> Content-Type: text/html
>>
>> I am requesting the RDF/XML representation of the information 
>> resource in question via it's URI, but not getting a redirect 
>> to the RDF representation at:
>> <http://www.johngoodwin.me.uk/pubs/data/pub1> .
>>
>> You're 200 OK in it's current form throws off RDF User Agents 
>> such as our RDF Browser [1] and Data Explore extension for 
>> Firefox [2] which will do the following:
>>
>> 1. Ask for an RDF/XML representation via Content Negotiation 
>> 2. If we don't locate an RDF information resource from step 
>> 1;  we will scan for <link rel="relevant-predicate" .../>, 
>> GRDDL, RDFa 3. Normalize 4. Expose RDF graph
>>
>> We don't expect a 200 OK for an RDF requests with the 
>> resource in question being an HTML representation, so right 
>> now, we never get to discover the RDF information resource.
>>
>> Solution: just 303 to the RDF information resource that 
>> matches RDF representation request.
>>
>> Then I should see: http://tinyurl.com/5he54t by starting at: 
>> http://www.johngoodwin.me.uk/pubs/description/pub1
>> instead of what I see currently at: http://tinyurl.com/6lkuaj
>>
>> Links:
>>
>> 1. http://demo.openlinksw.com/rdfbrowser2
>> 2. https://addons.mozilla.org/en-US/firefox/addon/8062
>>
>> -- 
>>
>>
>> Regards,
>>
>> Kingsley Idehen	      Weblog: 
>> http://www.openlinksw.com/blog/~kidehen
>> President & CEO 
>> OpenLink Software     Web: http://www.openlinksw.com
>>
>>
>>
>>
>>
>>
>>     
>
>
>   


-- 


Regards,

Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com
Received on Wednesday, 30 July 2008 13:18:40 UTC

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