Planet Drupal Rich Snippets with Drupal 7 and RDFa

Back in June, Google, Bing and Yahoo! announced a joint effort to build a schema for describing content the web. The first workshop took place last week in Mountain View, CA. I had the chance to participate in the event, and meet the folks behind as well as other members of the web community such as Tantek Celik (Microformats), Ian Hickson (HTML5), Ben Adida & Ivan Herman (RDFa), Dan Brickley (FOAF) and many others. RV Guha from Google announced several interesting partnerships:

Lots going on around! You can read Eric Franzon's report for more details: Workshop – A Path Forward.

The Definitive Guide to Drupal 7: Semantic Web, Security and so much more

I’ve been quiet about my involvement in this daunting project, but now that the book is finally complete and has hit the book stores, it’s time to talk about it. It all started more than two years ago when Benjamin Melançon (the instigator of this crazy project) asked me if I would be interested in helping him write a book on Drupal. It was when I was traveling on the East Coast spreading the word about Drupal and RDF (around the time of DrupalCon DC 2009). I was honored and agreed to participate. Things were very much up in the air at the time, and Ben didn’t really have any plan yet on how this would become real. In any event, by the end of the year Ben had put me and a few others in touch with some Apress folks. At the beginning of 2010, we had a contract and a list of about 10 authors, with an initial table of contents. Every few weeks or so we would see the list of authors increasing (with some dropping out and being replaced by others). Ben would surely have more insight into all the work he did to recruit authors, but that’s what I saw from my standpoint. I found it interesting to see so many authors on the same book, and wondered how all this bazaar of expertise would eventually turn out to fit in the same book. Each chapter was written by only one or two people, so that made it easy to break down the tasks and keep the authors organized.

I originally came on board to write on the topic of the Semantic Web, RDF and RDFa in Drupal, this is Chapter 28: “Spice Your Content Up With Tasty Semantics”. I’ve tried to cover the RDF core API as much as possible. Covering RDF in contrib was challenging given how fast it evolves, but I’ve put in enough pointers for people to find up to date information when they get to the chapter (including the new RDF Extensions and the merge of SPARQL Endpoint into the main SPARQL module). Thanks to Jeannie Finks, Ed Carlevale, Lin Clark, Oshani Seneviratne, Nick Maloney, and Boris Mann for their review and inspiration on this chapter.

As I was reviewing some other chapters of the book, I felt something was missing. Being a member of the Drupal Security Team, I could not find any reference to security in the list of chapters. Some chapters touched on the topic, but none really dealt with how the Drupal project and its community deals with security. That’s how I ended up with a second chapter on my plate, Chapter 6: “Security in Drupal”, which covers what to do to keep your site secure, how to react when you discover a vulnerability in a module, etc. Thanks to Greg Knaddison, Ben Jeavons, and Nick Maloney for reviewing this chapter.

I want to really thank my wife, Diliny, who has been very supportive throughout the entire time, making time aside so I could focus on the book, sacrificing many evenings and weekends. Thank you Diliny!

Among the chapters I have reviewed, my favorites are Jacine’s chapters on theming (chapters 15 and 16). Don't get me wrong, no offense to any other authors, I've been pleased with the content of the other chapters I've read! Plus there are some chapters I haven’t had the time to review (though others did). Given that I’m not a themer, I learned quite a lot from these theming chapters: they helped me to glue together some knowledge of theming which was scattered in my brain and needed some bigger picture to make more sense.

If you want to buy a great book about Drupal, with a wide range of expertise from the community condensed into 38 chapters, 9 appendices, 1000+ pages, buy our book! See all your purchase options at

The Definitive Guide to Drupal 7 at DrupalCon London

If you’re in London this week, you can meet some of the authors of the Definitive Guide to Drupal 7 at DrupalCon and get your copy of the book signed! If you want to check out the book and see how much it weights, look for the Wunderkraut booth, on the first floor on the left of the Acquia room (marked as booth 20 on the venue map), or ask Florian Loretan. I hear there will even be a book give away everyday for the winner of the Lego Bootstrap game organized at the Wunderkraut booth.

Background research work leading to RDF in Drupal 7 released as part of my Master's thesis

Oct 22nd, 2010 NUIG graduation leaflet (Photo credit: Anna Dabrowska)

Today it's about time to make my M.Sc. thesis available online. The review process took a long while, but I finally graduated from DERI, National University of Ireland, Galway last October. That's more than a year after I submitted my thesis and actually left Galway to move to Boston.

RDFa in Drupal 7: last call for feedback before alpha release

The first alpha release of Drupal 7 will be created next Friday Jan 15th. We've already incorporated most of the feedback we received from the semweb community so far, but I wanted to give the community a last chance to review the RDFa markup and the default RDF mappings we use before it's too late. I should emphasize that all the markup and default RDF mappings that we ship in core will be pretty much set in stone after the stable release of Drupal 7, hence this call for feedback. Site administrators who care about semantics will be able to alter these mappings by installing extra modules, but many people (read several 10K sites) will just install Drupal 7 and not care about the semantics it generates. Therefore we want to make sure the RDFa generated by Drupal out of the box is somewhat correct and does not make folks from the semantic/pedantic web community angry :) - we've tried to keep the semantics as generic as possible for that reason.

RDF mappings

I've created a diagram representing the default semantics of the core data structure which has been committed and I would appreciate feedback on the RDF terms we've used.

Drupal 7 core RDF schema

RDFa markup

To make the RDFa markup review process easier, I've updated the usual testing site at It features a blog post with some comments which represents a typical Drupal 7 page annotated with RDFa. Some other pages have been randomly generated to be able to test the tracker which acts as a very simple sitemap in RDFa.

Status of RDF in Drupal (November 09) and wrap up of ISWC2009

ISWC 2009 background -

I had the pleasure to give a presentation of the paper "Produce and Consume Linked Data with Drupal!" at ISWC2009 last, and I was very honored we won the Best Semantic Web in Use Paper award! The 30 minutes of presentation + Q/A passed very quickly and I didn't have much time to expand on the status of RDF in Drupal 7 vs. Drupal 6 after describing the inner workings of the modules we developed. I'm sure this will also interest some people outside the attendees. First of all, the current stable version of Drupal is Drupal 6 (the latest version at the time of this writing being Drupal 6.14). This is the version on which we started to implement the contributed modules presented at ISWC2009, namely RDF CCK, RDF external vocabulary importer (Evoc), SPARQL Endpoint and RDF SPARQL Proxy. Contributed modules means they do not get included in the core Drupal package, but people can download them from for free and drop them on their server so Drupal core can be extended. These 4 modules work pretty well on Drupal 6, you can get RDF export in RDF/XML, N-Triples, turtle, json. However generating RDFa is not very easy as it requires to patch the CCK on which we rely to generate the content pages and store the various field data. We made sure this would not be a problem in the next version of Drupal (Drupal 7) which is still under development, and due to be released sometime next year.

Produce and Consume Linked Data with Drupal!

Drupal in the Linked Data CloudProduce and Consume Linked Data with Drupal! is the title of the paper I will be presenting next week at the 8th International Semantic Web Conference (ISWC 2009) in Washington, DC. I wrote it at the end of M.Sc. at DERI, in partnership with the Harvard Medical School and the Massachusetts General Hospital which is where I am now working.

It presents the approach for using Drupal (or any other CMS) as a Linked Data producer and consumer platform. Some part of this approach were used in the RDF API that Dries committed a few days ago to Drupal core. I have attached the full paper, and here is the abstract:

Currently a large number of Web sites are driven by Content Management Systems (CMS) which manage textual and multimedia content but also - inherently - carry valuable information about a site's structure and content model. Exposing this structured information to the Web of Data has so far required considerable expertise in RDF and OWL modelling and additional programming effort. In this paper we tackle one of the most popular CMS: Drupal. We enable site administrators to export their site content model and data to the Web of Data without requiring extensive knowledge on Semantic Web technologies. Our modules create RDFa annotations and - optionally - a SPARQL endpoint for any Drupal site out of the box. Likewise, we add the means to map the site data to existing ontologies on the Web with a search interface to find commonly used ontology terms. We also allow a Drupal site administrator to include existing RDF data from remote SPARQL endpoints on the Web in the site. When brought together, these features allow networked RDF Drupal sites that reuse and enrich Linked Data. We finally discuss the adoption of our modules and report on a use case in the biomedical field and the current status of its deployment.

Half way through the RDF code sprint - Google Announces Support for RDFa

We're half way through the sprint and we just heard that Google has announced support for RDFa. What a coincidence, surely another sign proving Drupal's heading in the right direction! Now is time for some update on the sprint.

During day 1, we decided to split the group into two in order to enable some parallel developement and to make use of the 2 main skills we had at hand: RDF semantics and Drupal coding.

RDFa in Drupal: Bringing Cheese to the Web of Data

"RDFa in Drupal: Bringing Cheese to the Web of Data" is the title of our short paper which was recently accepted at the 5th Workshop on Scripting and Development for the Semantic Web. It seems that the topic of food on the semantic web is the new black as this paper comes out at the same time as Boris Mann's announcement about the Open Restaurants aka "BaconPatioBeer".

This paper illustrates how a CMS like Drupal can be used on the Semantic Web and make every Drupal site part of the growing Web of Data. We created a cheese review site as a use case. It relies on the RDF API and the RDF CCK modules.

The good news is that we are working to get this RDF goodness into Drupal core! We are organizing an RDF code sprint. This sprint builds on Dries' ideas expressed in his recent posts Drupal, the semantic web and search and RDFa and Drupal. With RDF in the core of Drupal and RDFa output by default, it's dozens of thousands of websites which will all of a sudden start publishing their data as RDF.

So far, Stéphane Corlosquet, Florian Loretan, Benjamin Melançon and Rolf Guescini have signed up. How about you?

Some others are willing to come but cannot afford the trip until some funding is secured. To help us fund the sprint and bring more Drupal rockstars on board, please consider making a donation using the ChipIn widget on this page. The money will be used to cover flight, food and hotel costs for the sprinters. All sprinters are generously donating their time to make this happen. It would also be great to fly in a few additional people with extensive testing and Fields experience. Any excess money will be used to add more people, or will be donated to the Drupal Association.

The Semantic Web strikes again

Exciting times for the Semantic Web in Drupal...

Harvard IIC and SCF

Today is my first day at Harvard's Initiative in Innovative Computing where I'll work on the Drupal based Science Collaboration Framework (SCF) project with Tim Clark, Sudeshna Das and Benjamin Melançon. I had the chance to meet Tim last year when he visited DERI and presented the SCF project. We'll work on aligning the efforts which were put into SCF with the efforts of the Drupal community in terms of RDF. We will see what requirements are emerging from a project such as SCF and contribute them back to the Drupal community.

The awakening of the Irish Drupal community

The first Irish Drupal meetup happened in Galway in January 07. Since then, Alan and myself have tried to convinced the Drupal users based in Dublin to get together and organize a Drupal event in Dublin. It was great to have this happen last Saturday with such a high number of attendees: 74 people! Thanks to Stella and Heather for all the marketing work!

All sorts of people came out to the event: folks from Google, IBM, Ericsson, some civil servants, many students from the various Dublin universities and freelance developers. We even had people visiting from the UK. Some were experts in PHP or other languages and were interested in learning about Drupal itself in order to contribute their expertise in coding and security. Some others were keen on creating new ties with the Open Source world in general. The gender ratio was better balanced than the regular 10% that we have come to expect at Drupal events.


Subscribe to RSS - Planet Drupal