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RE: Resolving references against base URIs

From: Paul Grosso <pgrosso@arbortext.com>
Date: Thu, 11 Apr 2002 10:10:49 -0500
Message-Id: <4.3.2.7.2.20020411100800.01c8bef0@172.27.10.30>
To: "Williams, Stuart" <skw@hplb.hpl.hp.com>, "'Jeremy Carroll'" <jjc@hplb.hpl.hp.com>
Cc: www-xml-linking-comments@w3.org, uri@w3.org
At 15:45 2002 04 11 +0100, Williams, Stuart wrote:
>Hi Jeremy,
>
>Hmmm....
>
>> e,f,i,j,k,l
>> Base does apply to same document references in RDF/XML
>
>I think that you're changing the semantics of URI references as defined in
>RFC2396, particularly section 4.2, same document references. I think your
>answers would be correct only for those cases where the in-scope base URI
>and the URI from which the document were retrieved are the same.

Stuart,

I'm not sure what you are saying here--can you expand?  I haven't been able
to see Jeremy's HTML file, and I'm not sure I understand what his answers
are in the cases he lists below, but I don't see how the in-scope base URI
and the document's retrieval URI could affect same document references.

paul

>Regards
>
>Stuart
>--
>> -----Original Message-----
>> From: Jeremy Carroll [mailto:jjc@hplb.hpl.hp.com]
>> Sent: 10 April 2002 18:43
>> To: uri@w3.org
>> Cc: www-xml-linking-comments@w3.org
>> Subject: Resolving references against base URIs
>> 
>> 
>> 
>> This is a comment about RFC 2396 that I have been actioned to 
>> send on behalf
>> of the W3C RDF Core Working Group [1]
>> 
>> The key issue concern resolving same document references 
>> and/or resolving
>> against non-hierarchical URIs.
>> 
>> These have been causing us difficulty in using xml:base
>> 
>> As one of our deliverables we produce test cases [2].
>> 
>> A summary table of our URI resolution problems is as follows;
>> the answers we have agreed are in the attached HTML file.
>> 
>> 
>> EASY:
>> a "http://example.org/dir/file"      "../relfile"
>> b "http://example.org/dir/file"      "/absfile"
>> c "http://example.org/dir/file"      "//another.example.org/absfile"
>> 
>> GETTING HARDER:
>> d "http://example.org/dir/file"      "../../../relfile"
>> e "http://example.org/dir/file"      ""
>> f "http://example.org/dir/file"      "#frag"
>> 
>> MASTER CLASS:
>> g "http://example.org"               "relfile"
>> 
>> h "http://example.org/dir/file#frag" "relfile"
>> i "http://example.org/dir/file#frag" "#foo"
>> j "http://example.org/dir/file#frag" ""
>> 
>> k "mailto:Jeremy_Carroll@hp.com"     "#foo"
>> l "mailto:Jeremy_Carroll@hp.com"     ""
>> m "mailto:Jeremy_Carroll@hp.com"     "relfile"
>> 
>> 
>> We have reached consensus on and approved all these tests 
>> except for the
>> last which some of us consider an error and others resolve as 
>> indicated in
>> the html file.
>> 
>> The rationales for our views are approximately as follows:
>> 
>> d "http://example.org/dir/file"      "../../../relfile"
>> 
>> [[[RFC2396
>>    In practice, some implementations strip leading relative symbolic
>>    elements (".", "..") after applying a relative URI 
>> calculation, based
>>    on the theory that compensating for obvious author errors is better
>>    than allowing the request to fail.
>> ]]]
>> Not permitted in RDF/XML.
>> 
>> e,f,i,j,k,l
>> Base does apply to same document references in RDF/XML
>> 
>> g
>> Failure to insert / is a bug with RFC 2396
>> 
>> h,i,j
>> Strip frag id from base uri ref before resolving.
>> Notice j is particularly surprising.
>> 
>> k,l
>> Same document reference resolution even works for 
>> non-hierarchical uris.
>> 
>> m
>> - no consensus
>> 
>> 
>> The test suite is structured as follows:
>> 
>> The positive tests on the test cases web site show a usage of 
>> xml:base in
>> RDF/XML and the resolution of that usage in terms of the RDF 
>> graph produced
>> (with absolute URI ref labels). Each test consists of two 
>> files, an RDF/XML
>> document and an n-triple file (substitute .rdf with .nt in 
>> the URL), being a
>> list of the edges of the graph.
>> 
>> The negative test case shows possibly illegal usage of 
>> xml:base in RDF/XML.
>> 
>> 
>> Our intent is that these tests will be part of a normative 
>> revision of the
>> RDF recommendation.
>> 
>> Jeremy Carroll
>> HP Rep W3C RDF Core WG
>> 
>> 
>> 
>> [1]
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Apr/0008.html
>> 2002-03-22#4:  jeremy Send mailto:uri@w3.org with appropriate tests
>> 
>> [2]
>> http://www.w3.org/2000/10/rdf-tests/rdfcore/xmlbase/
>> 
>> 
Received on Thursday, 11 April 2002 11:11:58 GMT

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