Comments on: New W3C GRDDL service

By: Nodalities » Blog Archive » This Week’s Semantic Web

Nodalities » Blog Archive » This Week’s Semantic Web — Thu, 17 Apr 2008 17:01:57 +0000

[...] W3C GRDDL service – announcement – also [...]

By: Laurent Saint Jean

Laurent Saint Jean — Sun, 16 Sep 2007 19:27:08 +0000

This service seems fabulous, but i get the utf-8 error two when trying the service on 3 sites i’ve tested.

And when trying to parse this very blog, i get a blank page on Mac-Firefox2 (scripts are enabled)

I still have the encoding stipulated though.

By: Dave Beckett

Dave Beckett — Fri, 07 Sep 2007 18:30:05 +0000

Turns out that due to the way I use libxml as a push parser, there is no way to pass in an external
encoding: xmlCreatePushParserCtxt:

xmlParserCtxtPtr
xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax, void *user_data,
const char *chunk, int size, const char *filename);

It would either need libxml to add a new API, I would have to call it a different way
with knowledge of it’s internals (yuck) or it would need internal changes to libxml.

By: masaka

masaka — Wed, 05 Sep 2007 00:53:44 +0000

OK, I added an XML declaration to my profile, and got proper result.

thank you for quick response!

By: Dom

Dom — Tue, 04 Sep 2007 13:29:39 +0000

Looking at it more closely, it happens because the profile document http://www.kanzaki.com/ns/metaprof has its encoding only declared in the HTTP header, not in the XML encoding declaration.

Of course, this is acceptable per the spec, so I have reported a bug in the underlying library:
http://bugs.librdf.org/mantis/view.php?id=231
(it ties back to a bug I had reported a while back in libxml2 I fear:
http://bugzilla.gnome.org/show_bug.cgi?id=104790 )

By: Dom

Dom — Tue, 04 Sep 2007 13:14:01 +0000

Indeed, that’s a bug; I’m looking into it, but haven’t found a straightforward workaround yet…

By: masaka

masaka — Tue, 04 Sep 2007 02:59:53 +0000

Hi, nice to see new service.

Unfortunately, this doesn’t seem to work well with a profile based GRDDL whose encoding is not UTF-8 (OK for link based GRDDL). For example, I can get a proper result from http://www.kanzaki.com/docs/sw/ using XSLT service, but “Input is not proper UTF-8″ error from new service.

Could you check for this issue ?

thank you.

By: dom

dom — Wed, 29 Aug 2007 06:47:07 +0000

Indeed (with the caveat that not all microformats are GRDDL-friendly).

By: Justin Thorp

Justin Thorp — Wed, 29 Aug 2007 01:15:03 +0000

So for me as the end-user I don’t really have to worry about GRDDL or RDF, I just have to make sure that my blogroll is marked up using the XFN microformat? Someone else is going to screen scrape my blog to gather my relationships data and translate that into something more Semantic Web friendly?

By: dom

dom — Tue, 28 Aug 2007 14:22:42 +0000

I fear it would be too long to answer that question in a single blog comment but hopefully the GRDDL primer answers some of it already:

Another choice is to use microformats. A microformat that allows for more information about friends to be gleaned from the document is XFN, " XHTML Friends Network". Examples of such relationships are friends, colleagues, co-workers, and so on, as given in this example file.

Since XFN relationships are embedded in anchor (a) elements, they can be expressed in RDF in a variety of ways. Given Jane's HTML document uses the XFN microformat, a GRDDL transformation can extract RDF data. These descriptions would allow a RDF spider (a "scutter") to follow links to additional RDF content that may include more XFN, vCard, or FOAF descriptions.

To make a long story short, a microformat that uses a profile URI can be made GRDDL-friendly very easily, and thus provide a wealth of data to the semantic Web; these data can then be used and re-used, typically in mash-ups services.

By: Justin Thorp

Justin Thorp — Tue, 28 Aug 2007 14:10:20 +0000

So for the average Joe developer, what does this mean to them? Will this take my microformatted data and turn it into RDF? If so, once the data is in RDF what would we do with it?