Category Archives: FOAF FOAF Project

SKOS Output from WordPress

Waiting for the bus to the medieval banquet at Dunguaire Castle for the FOAF Galway Workshop (photos), I remembered I had tweaked the FOAF Output Plugin to also output SKOS concepts — and possibly mappings to others’ categories.

Get it before your neighbour, the FOAF Output Plugin, version 1.11 — the Galway Release…

See also the SKOS development toolshed.

In passing, being here in Galway/Ireland is great, not only do I get to meet a lot of smart and interesting people, very much like at FOAF Camp, I also get to add another country to my list of visits

WordPress Plugin: seeAlso’s

What is now several weeks ago, Christoph Görn hacked a bit on my FOAF Output plugin, and asked for seeAlso links to be included. Short of the mythical WordPress triple store (factory?) I couldn’t see a better way to do it than building on the concept from the Semantic Visits add-on: Using the link manager.

I challenged Danny Ayers to write the plugin/add-on, but he’s been busy lately, with the RSS book and all, so here it is, the seeAlso’s Plugin (view source). While I was at it, I also fixed a few buglets in the FOAF Output Plugin and added trust ratings for friends and bio:olb.

The current version is 1.0 (this blog entry will serve as a changelog).

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“They Rule” as RDF

Yesterday Dan Brickley reported success on getting Josh On to release “They Rule” data. This has been a somewhat long standing goal for the FOAFCorp effort, and According to Josh, who created it, the data is free.

Dan asked for conversion into RDF/XML, so here it is — created by, which was inspired by Dan’s own scripts from last year: “They Rule” 2004 as RDF/XML (gzipped, 175k) or “They Rule” 2004 as NTriples (gzipped, 168k)

I’m sure Jim Ley will have this loaded into foafnaut before long, for everyone to browse…

WordPress Plugin: Semantic Visits

When I came back from Madrid, after the Image Decription workshop, a few days in the city, and a hefty party in Getafe, I realised I could add another country to my list of visits.

The nice folks at World66 have created a nice interface for generating an image with visited countries highlighted, but while it would be easy to check a few boxes and copy the code to somewhere on my blog pages, that wouldn’t make it possible for the semantic web to figure out where I’ve been. For that reason, I decided to mint a set of vocabulary terms for visits according to Norm Walsh’s country counting rules, collected in the visit vocabulary, and have WordPress output the information in my FOAF profile – thanks to the extensibility of my FOAF Output Plugin. Of course, the FOAF Explorer now also understands these terms, displaying maps of the world, Canada and USA when appropriate — see for yourself!

Thus, here is a new plugin, the Semantic Visits Plugin (view source).

The current version is 1.1.

Changes since 1.0:
  • Added visits to Canadian regions.
  • Fixed “wrong” code/name/etc. properties.
  • The URIs for US states are now correct, pointing at the ontology containing state definitions instead of which only contains classes and properties.

Continue reading WordPress Plugin: Semantic Visits

WordPress Plugin: FOAF Output

A while ago I hacked WordPres into emitting FOAF, but even though it worked fine, the amount of WordPress-tweaking wasn’t for the faint of heart.

Since then, I have looked a little deeper into WordPress, and now it’s finally ready: The FOAF Output Plugin (view source).

Note: If you want to try running this with WordPress > 1.2, please fix the .htaccess rewrite rule for the author pages like this, otherwise the FOAF file will result in a 404:

RewriteRule ^author/([^/].+)/?$ /<SITEHOME>/index.php?author_name=$1 [QSA,L]

The current version is 1.17 (released 2005-08-31).

Changes since 1.16:
  • Fixed errant line breaks in links.
  • Added generator comment to RSS output.
Changes since 1.15:
  • Added oneline bio on profile page, not HTML-escaped.
  • Added link to RSS channel from author list.
  • Tweaked prefix usage for namespaces.
Changes since 1.14:
  • Added check for array being returned from get_the_category().
  • Added check for get_Lat and get_Long for > 1.2 compatibility.
Changes since 1.13:
  • Fixed category/interest when no categories were found.
  • Changed skos:externalID to dc:identifier.
  • Updated SKOS generation with SKOS extensions vocabulary.
  • Fixed generation of author list URI.
Changes since 1.12:
  • Changed a wrong foaf:made to foaf:page, caught by Ian Davis.
  • Fixed erroneous output of homepage URI on profile page.
  • Fixed a problem with statements being added to Atom feeds, thanks Danny/Sam.
Changes since 1.11:
  • Added blog-wide FOAF output (blogroll) with seeAlso’s to authors’ individual files (example).
Changes since 1.10:
  • Added SKOS output (example) and enhanced RSS output.
  • Added document level RDF/XML API hook, foaf_output_profile_rdf_document, to allow for additional properties by add-ons, e.g. generator information.
  • Fixed possible missing namespace declarations for dcterms in RSS/Atom.
  • Tweaked initialisation code to increase reusability.
Changes since 1.9:
  • Fixed limited interest generation for HTML profile page.
  • Multiple URIs per interest is now handled correctly (if separated by whitespace).
  • Only categories with posts by author are deemed “interesting”.
  • Added bio:olb per B.K. DeLong’s suggestion.
  • Added trust ratings for friends.
Changes since 1.8:
  • Renamed foaf_output_the_date to get_foaf_output_profile_page to better reflect the functionality.
Changes since 1.7:
  • Improved identification of “active” author / user.
  • Now really only shows profile on first archive page, even in paged mode.

Continue reading WordPress Plugin: FOAF Output