Re: odrl-ISSUE-16: Use of @base and relative URIs in examples [ODRL 2 Ontology]

Hi,

I am no expert in this topic and after reading once and again the spec I 
am still not sure...
But I made a small test, and checked that upon normalization,

"http://example.com//asset:9898"

and

"http://example.com/asset:9898"

happen to be equivalent. We should opt for the "canonical" form, though...

Víctor


El 13/11/2013 9:45, Michael Steidl (IPTC) escribió:
> Hi Mo,
> actually 5.2.3 Merge Paths of RFC3986 tells more about this issue than 5.1.1:
> It writes down:
> The pseudocode above  (in 5.1.x) refers to a "merge" routine for merging a
>     relative-path reference with the path of the base URI.  This is
>     accomplished as follows:
>     o If the base URI has a defined authority component and an empty
>        path, then return a string consisting of "/" concatenated with the
>        reference's path; otherwise,
>     o  return a string consisting of the reference's path component
>        appended to all but the last segment of the base URI's path (i.e.,
>        excluding any characters after the right-most "/" in the base URI
>        path, or excluding the entire base URI path if it does not contain
>        any "/" characters).
>
> How the components of a URI are split up is shown in section 3 of the RFC. A URI like http://example.com/ has an authority component of "example.com" and a path of "/", therefore the second bullet of 5.2.3 applies.
> >From my reading this makes
> mergedURI = "http://example.com/" + "/asset:9898" = "http://example.com//asset:9898"
> ... which is not the same as http://example.com/asset:9898 in the explanation. And that's my point.
>
> Michael
>
>> -----Original Message-----
>> From: Mo McRoberts [mailto:Mo.McRoberts@bbc.co.uk]
>> Sent: Tuesday, November 05, 2013 11:39 AM
>> To: ODRL Community Group
>> Subject: Re: odrl-ISSUE-16: Use of @base and relative URIs in examples
>> [ODRL 2 Ontology]
>>
>> Hi Michael,
>>
>> I don?t believe this is correct ? I?m about 99% sure that @base behaves as
>> <base href=???> does in HTML; the strings are not strictly concatenated, but
>> instead the possibly-relative URI is rebased against the value of @base. The
>> Turtle spec specifically cites RFC3986 section 5.1.1, "Base URI Embedded in
>> Content".
>>
>> e.g., if you had:
>>
>> @base <http://example.com/foobar> .
>> @prefix foaf: <http://xmlns.com/foaf/0.1/> .
>>
>> </baz#id> a foaf:Agent .
>>
>> then the triple is expanded to:
>>
>> <http://example.com/baz#id> <http://www.w3.org/1999/02/22-rdf-syntax-
>> ns#type> <http://xmlns.com/foaf/0.1/Agent> .
>>
>> Live example of the above:
>>
>> Turtle: http://ptah.bencrannich.net/2013/misc/test
>>
>> N-Triples:
>> http://lodscope.parthenon.org.uk/index.text?uri=http://ptah.bencrannich.n
>> et/2013/misc/test
>>
>> So while it?s true that the URIs have one character more than they strictly
>> need, it doesn?t make any difference to the parsing result.
>>
>> M.
>>
>> On  2013-Nov-05, at 09:29, ODRL Community Group Issue Tracker
>> <sysbot+tracker@w3.org> wrote:
>>
>>> odrl-ISSUE-16: Use of @base and relative URIs in examples [ODRL 2
>> Ontology]
>>> http://www.w3.org/community/odrl/track/issues/16
>>>
>>> Raised by: Michael Steidl
>>> On product: ODRL 2 Ontology
>>>
>>> All the Turtle examples in the Ontology draft are using @base this way:
>>> @base <http://example.com/> .
>>> @prefix odrl: <http://w3.org/ns/odrl/2/> .
>>> ...
>>> odrl:target </asset:9898> ;
>>> ....
>>>
>>> The description of this example states that the URI for the asset is
>> http://example.com/asset:9898
>>> Reading the Turtle specs I conclude that the strings of @base and the
>> relative URI are concatenated making http://example.com//asset:9898
>> which is not the same as described.
>>> Wouldn't it be better to omit the leading slash in the relative URIs?
>>>
>>>
>>>
>>
>> --
>> Mo McRoberts - Analyst - BBC Archive Development,
>> Zone 1.08, BBC Scotland, 40 Pacific Quay, Glasgow G51 1DA,
>> MC3 D6, Media Centre, 201 Wood Lane, London W12 7TQ,
>> 0141 422 6036 (Internal: 01-26036) - PGP key CEBCF03E
>>
>>
>>
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>


-- 
Víctor Rodríguez-Doncel
D3205 - Ontology Engineering Group (OEG)
Departamento de Inteligencia Artificial
Facultad de Informática
Universidad Politécnica de Madrid

Campus de Montegancedo s/n
Boadilla del Monte-28660 Madrid, Spain
Tel. (+34) 91336 3672
Skype: vroddon3

Received on Wednesday, 13 November 2013 09:29:30 UTC