Seth Ladd's Blog

We now have two extensions to Thunderbird that can read the X-FOAF header. Phil Wilson took the MessageFaces source code and modified it for X-FOAF . Woohoo, Phil! Meanwhile, Chris Schmidt has released and announced Thunderbird FOAF . It, too, is based on existing code . Woohoo, competition! A big thanks to Jens Bannmann, who created the MessageFaces extension. He outlines the difficulties of working with Thunderbird headers in extensions: Just to warn you: There are a few obstacles here. The first is that unless the user sets "View all headers", only the standard headers are sent to the UI. Unfortunately, the set of headers is hard-coded into the core (see https://bugzilla.mozilla.org/show_bug.cgi?id=236954 for future work to change this). To work around this, MessageFaces has a mechanism to switch the All Headers preference on just before the message is loaded, and to switch back before it actually gets displayed. This is a really, really fragile hack, but we hav

I'm looking around for a dedicated hosting provider. I need a place to run my FlickrRdf code, plus other semwebby goodness. I'd like a dedicated machine so that I'll have all my options open. Any suggestions for a good dedicated hosting provider? I just need the basics, and I'm looking to spend around US$100/month. Oh, and it has to run Linux. Thanks!

Leigh Dodds created Slug: A Simple Semantic Web Crawler . Nice job Leigh! Because it's in Java, I'll be able to integrate into my FOAFverse work. Back in March I was tinkering with writing a Scutter. I'd never written a web crawler before, so was itching to give it a go as a side project. I decided to call it Slug because I was pretty sure it'd end up being a slow and probably icky; crafting a decent web crawler is an art in itself.

After taking a brief survey, it seems that X-FOAF is used more. I changed my Thunderbird installation to send out X-FOAF headers instead of X-FOAF-URI headers. Just trying to remain consistent.

Ian Davis saw my post on FOAF and Thunderbird , and found out how to add a FOAF URI to Thunderbird as a mail header . Thanks Ian! Ian said: Seth Ladd had an interesting idea: adding an x-foaf header to outgoing emails. I wondered if this was possible in Thunderbird and after a bit of digging I found that you can do it by adding the following to prefs.js in your Thunderbird profile directory I changed the code for the prefs file just a bit. I used: user_pref("mail.identity.id1.headers", "foaf"); user_pref("mail.identity.id1.header.foaf", "X-FOAF-URI: http://www.picklematrix.net/foaf.rdf"); I changed X-FOAF-Uri to X-FOAF-URI , and the values of the idXXX.headers pref must match the idXXX.header.YYYYY . Now I'm sending FOAF around the world! Part two: Setting up gmail to send arbitrary headers.

Thinking about FOAF and Thunderbird integration , for it all to work, FOAF documents should be signed ( PGP / GPG for instance). A nice little trust web would emerge. Signing a FOAF document (or, more accurately, a set of triples) would mean "I verify that these triples are correct to the best of my knowledge" Same principles would apply from signing others' PGP keys (from a trust perspective). So, in an effort to see if we can sign RDF triples, I stumbled upon the Tech Report: HPL-2003-142: Signing RDF Graphs . The Jena guys do it again! From the article synopsis: However, it is possible to define a large class of canonicalizable RDF graphs, such that digital signatures for graphs in this class can be created and verified in O (n log (n)). Without changing its meaning, an arbitrary RDF graph can be nondeterministically pre-canonicalized into a graph of this class, before signing. The techniques in this paper are key enablers for the use of digital signature technol

What if FOAF was integrated into Thunderbird with Mozilla Thunderbird Extensions ? I would imagine it would be a nice way to add some extra trust into emailing. No longer would I have to include a document (vCard) with all my email. I can set an email header (X-FOAF) that has the URI to my FOAF file. My identity now lives on the web. My email client should know about and understand it. Some simple outcomes of FOAF and Thunderbird integration would be: "Who sent me this?", "What is the homepage of the person that sent me this?", "Does anyone else I know know this person?". More nifty features would be automatic PGP key downloading (linked to via FOAF) for the signed/encrypted email I just received. Time to learn XUL .

Stumbled on a great semantic web use case from mod-pubsub titled Imagine eBay Without The eBay . Commerce over the web should be as decentralized as the web itself. In such a world, search engines become more important, and pubsub becomes more important (as buyers and sellers regularly want to publish and subscribe to messages saying "I want to buy this" or "I want to sell this"). There's a very exciting future out there, waiting to be invented... Take it one step further: one of eBay's nice features is that of trust. You can see the user feedback and trust ratings for a buyer or seller from past transactions. Why does that data have to live only in eBay? Isn't my Amazon Marketplace identity and trust rating equally as important? I should be able to combine the two identities into one identity, and thus build twice as much trust. (btw, I've posted about this scenario before , but I never took it so far as to decentralize the actual buying and

I spent tonight working on the FlickrRdf module. This is decoupled completely from Foafverse now. FlickrRdf uses the Flickr Services and constructs RDF out of the XML . It sometimes has to combine multiple Flickr API calls to form one cohesive RDF document. I like the way this has turned out so far. Most of it is implemented with XSLT transformations. I'm caching the XSLT sheet in compiled form, and the end result RDF. This is a programming exercise as much as a semweb exercise, so progress is slower than normal as I take the time to think about how to implement it. Now that I've nearly implemented everything I want to (with the XML -> RDF stuff) I need to find a place to host it. It's a Java webapp, so not as easy to host as some PHP or the like.

The Flickr guys are giving a talk at the O'Reilly Emerging Technology Conference titled Web Services as a Strategy for Startups: Opening Up and Letting Go . Excerpt from the session description: Drawing on real world experience in designing, launching, and managing the Flickr API (available in REST/SOAP/XML-RPC), Butterfield's session gives an overview of the business decisions, product design goals, architecture, and technical implementation of a web service that has given rise to a thriving development community. In general, Flickr is on the right track with their services, and they are much appreciated. There are a few tweaks I'd like them to make (Get a list of groups a person is a member of, eg) but most importantly I'd like to get a SHA1 hash of a person's email . This would allow me to smush triples from all over the social networking sphere.