Re: Discussion with Ian and Henri about HTML5+RDFa (part 2/2)

Ben Adida wrote:
> Philip Taylor wrote:
>> I don't have any decent statistics, but I've got some quick
>> hacked-together data at http://philip.html5.org/data/cc-errors.txt
>>
>> [...]
> 
> Hi Philip,
> 
> Thanks for this info. I think you're talking about RDF in comments, the
> ugly old style we had, and the central reason we worked on RDFa :)

Ah, good point! I got them a bit mixed up. Anyway, it's good to see that 
there were problems with the RDF-in-comments syntax that have been 
avoided now :-)

> CC's new recommendation, since last summer, is to use RDFa such as:
> [...]
> 
> Note how this no longer includes the license details (just de-reference
> the license URL for that), so we expect this to be much more robust than
> the RDF in comments you analyzed.

"last summer" is a bit recent and my data is currently about a year old, 
but I still found 4 examples of that RDFa syntax, listed at 
http://philip.html5.org/data/cc-rdfa-extracts.txt

The markup in each case is different enough that it looks like people 
are editing these things by hand, not simply copying the untweaked 
output of a tool.

One of those uses <a href="www.invaligia.com" 
property="cc:attributionName" rel="cc:attributionURL"> which means it's 
talking about the nonexistent page 
http://www.invaligia.com/www.invaligia.com

Two are not well-formed XML within the Creative Commons block of markup; 
the other two are not well-formed XML in the rest of the page. So it's 
not possible to extract the RDFa with an XML parser -- you would have to 
use an HTML parser instead (and presumably add hacks to emulate XML 
Namespace processing).

Somewhat relatedly, there's another four pages that use rel="dc:type". 
One of those (http://bytestrike.blogspot.com/) has it near a CC license 
link and does not have an xmlns:dc declaration anywhere, suggesting a 
copy-and-paste error.

I should probably try downloading some more recent pages, to see if 
CC/RDFa usage is more common now...

-- 
Philip Taylor
pjt47@cam.ac.uk