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The slides from the day-long tutorial, REST in Practice, that Jim Webber and I gave at QCon San Francisco can be found here.

Also as part of QCon, I gave a talk, Beginning an SOA Initiative, the slides of which can be downloaded here.

Jim and I will be giving the REST tutorial at QCon London next year. We’re already planning plenty of changes so as to make it a little more hands-on and practical.

The slides from yesterday’s talk are here. Thank you to everyone who attended – there were some great questions both during and after.

I’ll be at the wonderful JAOO in Aarhus throughout most of next week (Monday, September 5th to Thursday, September 8th). On Tuesday I’m giving a talk, Hydras and Hypermedia, that reveals what your enterprise apps get up to when they cut loose at the weekends; if you’re curious, come along and meet Wired ERP and the DeeEmEs. The presentation is really my ticket to seeing talks from all the great speakers on Stefan Tilkov’s Is REST turning SOA’s promise into reality? track: Rachel Reinitz, Subbu Allamaraju, Mike Amundsen, Anne Thomas-Manes, and Stefan.

At other times in the week you’ll find me hanging around the ThoughtWorks booth, where besides an informal chat, you can schedule a 30-minute one-on-one meeting with one of the many ThoughtWorks consultants attending the conference.

Photo taken from ElDave’s Flickr stream under the Creative Commons licence

On Monday 20th July, Jim Webber and I, the golem and the frog, will be participating in the European Virtual ALT.NET (E-VAN). Colin Jack has already assembled a bunch of interesting questions, covering not only REST, but Guerrilla SOA, ESBs, consumer-driven contracts, and capability modeling.

The session will be on Live Meeting, at http://snipr.com/virtualaltnet.

Please join us on Monday, times below:

• France/Germany/Belgium: 8:00PM
• UK is: 7:00PM
• EST in the US: 2:00PM
• PST in the US: 11:00AM

Consider these links:

Example 1

<preceding>http://iansrobinson.com/0F449B535C2C</preceding>
<following>http://iansrobinson.com/796DC49C644E</following>

and

Example 2

<link rel="http://iansrobinson.com/resources/link-relations/preceding" href="http://iansrobinson.com/0F449B535C2C"/>
<link rel="http://iansrobinson.com/resources/link-relations/following" href="http://iansrobinson.com/796DC49C644E"/>

Functionally equivalent?

There are two separate concerns at play here: finding links, and understanding links. An application’s semantic space – the set of link relations it uses to annotate links – is extensible. Understanding targets an open set. The capability to find links, on the other hand, ought ideally target a closed set.

In Example 1, each element bears the weight of addressing both concerns. The ability to find links is pinned to an open set. In Example 2, by contrast, the link element belongs to a closed set, with the semantic variance broken out and herded into the rel attribute value. Much easier to find links belonging to Example 2 using an application-agnostic function, a LINQ for Links, as it were.

What happens when we extend an application’s semantic space?

Example 3

<preceding>http://iansrobinson.com/0F449B535C2C</preceding>
<following>http://iansrobinson.com/796DC49C644E</following>
<all>http://iansrobinson.com/22F4D1881C36</all>

Example 4

<link rel="http://iansrobinson.com/resources/link-relations/preceding" href="http://iansrobinson.com/0F449B535C2C"/>
<link rel="http://iansrobinson.com/resources/link-relations/following" href="http://iansrobinson.com/796DC49C644E"/>
<link rel="http://iansrobinson.com/resources/link-relations/all" href="http://iansrobinson.com/22F4D1881C36"/>

A client of Example 3 will likely only be able to report: “foreign markup found.” A client of Example 4 will be able to recognize the new link, though not necessarily understand the new rel value.