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Re: URIs in @rel and @property...

From: Niklas Lindström <lindstream@gmail.com>
Date: Tue, 17 Nov 2009 13:34:41 +0100
Message-ID: <cf8107640911170434ta1e8497u641738c5b83f78fa@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: Mark Birbeck <mark.birbeck@webbackplane.com>, Ben Adida <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>
Another point though. Isn't there a problem if prefixes are declared
for existing protocols?

When prefixes are declared for e.g.:

    xmlns:http="http://www.w3.org/2006/http#"
    xmlns:tag="http://example.org/tagging#"

With the proposed rules ("unsafe CURIE or URI"), wouldn't these:

    about="http://example.org/me"
    resource="tag:example.org,2009:item:1"

be resolved against those prefixes (instead of as-is)?

Best regards,
Niklas


2009/11/16 Niklas Lindström <lindstream@gmail.com>:
> Ah, but indeed! Good elephant-hunting Mark! ;) It's quite comforting
> that RFC 3986 is so precise about these things.
>
> (I should have known that -- I now recall reading that very same rule
> a couple of months ago when investigating the legality of non-escaped
> colons in URI:s. Only remembered half of it apparently.)
>
> Best regards,
> Niklas
>
>
> 2009/11/16 Ivan Herman <ivan@w3.org>:
>> Pfew...:-)
>>
>> Ivan
>>
>> P.S. Mark-the-elephant-hunter:-)
>>
>> Mark Birbeck wrote:
>>> Hi Ivan/Niklas,
>>>
>>> 2009/11/16 Ivan Herman <ivan@w3.org>:
>>>> Hi Niklas,
>>>>
>>>> Niklas Lindström wrote:
>>>>>> So is there an elephant?:-)
>>>>> I haven't followed this discussion to closely, so I want to check if
>>>>> this the following is considered:
>>>>>
>>>>> This usage will "muddle the waters" in cases when the relative URI:s
>>>>> contain colon, and there is a prefix with the same name as the leading
>>>>> part before that, right? Concrete (but contrieved) example:
>>>>>
>>>>> Given:
>>>>>     - base URI: <http://en.wikipedia.org/wiki/>
>>>>>     - prefix Talk: <http://example.org/schema/talk#>
>>>>>
>>>>> When:
>>>>>     @resource="Talk:Linked_Data"
>>>>>
>>>>> Then:
>>>>>     - URI becomes < http://example.org/schema/talk#Linked_Data>,
>>>>> instead of <http://en.wikipedia.org/wiki/Talk:Linked_Data>, which is
>>>>> might be expected?
>>>>>
>>>> Hm. You may found the elephant:-)
>>>>
>>>> Yes, in this case one would indeed get the example.org URI.
>>>>
>>>> The question is: is this use case so strong as to nullify the advantages
>>>> of using CURIE-s in @about? Indeed, wikipedia uses such URI-s with ':'
>>>> quite a lot but the user can of course put full URI-s into the value of
>>>> @about...
>>>>
>>>> Thanks!
>>>
>>>
>>> Whoah...slow down. :)
>>>
>>> "Talk:Linked_Data" is not a relative path!
>>>
>>> Forget prefixes, CURIEs, whatever...even if those things did not
>>> exist, how would a URI processor know whether "Talk:" is a scheme or
>>> just part of a relative path?
>>>
>>> RFC 3986 [1] addresses this in the following way:
>>>
>>>   A path segment that contains a colon character (e.g., "this:that")
>>> cannot be used as the
>>>   first segment of a relative-path reference, as it would be mistaken
>>> for a scheme name.
>>>   Such a segment must be preceded by a dot-segment (e.g.,
>>> "./this:that") to make a
>>>   relative-path reference.
>>>
>>> So, if people are using relative paths that contain colons, in the
>>> wild, then there's a problem, and that problem is completely
>>> independent of RDFa.
>>>
>>> Regards,
>>>
>>> Mark
>>>
>>> [1] <http://www.ietf.org/rfc/rfc3986.txt>
>>>
>>> --
>>> Mark Birbeck, webBackplane
>>>
>>> mark.birbeck@webBackplane.com
>>>
>>> http://webBackplane.com/mark-birbeck
>>>
>>> webBackplane is a trading name of Backplane Ltd. (company number
>>> 05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
>>> London, EC2A 4RR)
>>
>> --
>>
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
>>
>>
>
Received on Tuesday, 17 November 2009 12:35:35 UTC

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