W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > November 2008

Re: Not sure... (Re: Invalid namespace URI)

From: Peter Mika <pmika@yahoo-inc.com>
Date: Thu, 13 Nov 2008 13:39:40 +0100
Message-ID: <491C200C.5010403@yahoo-inc.com>
To: Ivan Herman <ivan@w3.org>
CC: public-rdf-in-xhtml-tf@w3.org

I'm not sure either... As I'm too lazy to read the whole spec, I did 
some testing in java, where...

URI uri1 = new URI("http://creativecommons.org/ns #");

throws a URI syntax exception

but interestingly

URI uri2 = new URI("http://creativecommons.org/ns%20#");

doesn't.

In any case, there is an appendix of the URI specification which seems 
to put the burden of removing whitespaces on the processing agent:

http://labs.apache.org/webarch/uri/rfc/rfc3986.html#delimiting

Quoting:

For robustness, software that accepts user-typed URI should attempt to 
recognize and strip both delimiters and embedded whitespace.

For example, the text

   Yes, Jim, I found it under "http://www.w3.org/Addressing/",
   but you can probably pick it up from <ftp://foo.example.
   com/rfc/>.  Note the warning in <http://www.ics.uci.edu/pub/
   ietf/uri/historical.html#WARNING>.

contains the URI references

   http://www.w3.org/Addressing/
   ftp://foo.example.com/rfc/
   http://www.ics.uci.edu/pub/ietf/uri/historical.html#WARNING

End quote.

Cheers,
Peter

Ivan Herman wrote:
> I actually wonder...
>
> RDFa uses the xmlns syntax for URI prefixing only. Ie, the only thing
> that counts is whether it is a valid URI. If the result of the
> processing is to generate
>
> http://creativecommons.org/ns&20#
>
> that _is_ a valid URI, isn't it? Ie, I guess the bug in the current
> distiller code is that URI-s should be properly quoted.
>
> Having said that, such setting is probably an error, so if there is a
> space in the string than a warning is probably in order. But, who knows,
> some crazy users may want to use such a URI...
>
> Ivan
>
> Ivan Herman wrote:
>   
>> Hi Peter,
>>
>> thanks for the note. I will have a look into it but yes, the tool should
>> probably warn...
>>
>> Ivan
>>
>> Peter Mika wrote:
>>     
>>> Hi All,
>>>
>>> We have found another corner case while looking at all the wonderful
>>> RDFa on the Web:
>>>
>>> The page at [1] contains:
>>>
>>>
>>> This
>>> work by <a
>>> xmlns:cc="http://creativecommons.org/ns
>>> #
>>> "
>>>
>>> which is probably not intended (the page is broken in some sense). When
>>> run through either the XSLT or the Distiller this
>>> becomes:
>>>
>>>      <cc:attributionName xmlns:cc="http://creativecommons.org/ns #">New
>>> Jersey State Auto
>>> Auction</cc:attributionName>
>>>
>>> which is normalized [1] as
>>> xmlns:cc="http://creativecommons.org/ns&#x20
>>> <http://creativecommons.org/ns&#x20>;#">
>>>
>>> It seems to me that what you get is XML well-formed but not
>>> namespace-well-formed [2] because the attribute value is not a valid URI.
>>>
>>> Not sure really what to do about this but the output is not very
>>> useful... should the tools raise some warning?
>>>
>>> Thanks,
>>> Peter
>>>
>>> [1] http://www.w3.org/TR/REC-xml/#AVNormalize
>>> [2] http://www.w3.org/TR/REC-xml-names/#Conformance
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> [1] http://www.njstateauto.com/preowned/index.cfm?make=Mercedes-Benz
>>>
>>>       
>
>   
Received on Thursday, 13 November 2008 12:40:32 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Thursday, 13 November 2008 12:40:33 GMT