April 30, 2005
Birthday Snapshot #3
Another of my annual birthday snapshots. What's going on in my life at the moment? I doubt you're interested, but I am. So there!
Home
Well we stopped thinking about the loft conversion and went ahead and had one done. What a nightmare that turned out to be. Dust, mess, and disruption I was expecting. Incompetence I wasn't. The builders mis-measured the dormer extension with the result that they had to widen it once the stairs arrived to be fitted. They did the widening last thing on a friday, didn't waterproof it properly and we suffered a bad leak. Too me best part of a day to get someone out to temporarily fix it.
General mismanagement, and slacking off, meant things went from bad to worse. A 4-6 week job turned into about 10 weeks. We suffered further leaks, terrible disruption (no roof means no heating), and general apoplectic rage, right up until 23rd December.
At least its done now and, in the end, we're happy with the finished job. Maybe this is how all building projects go, but I doubt it. The friends who recommended the builder didn't have anywhere near as much trouble, but I'd think twice about using these guys if you're looking for a builder in Bath.
That aside, home life at the Dodds' is pretty sweet at the moment. Ethan is really enjoying nursery and has taken to it without any problems. Martha seems to be growing up rapidly and constantly amazes us with her vocabulary.
Work
I finished that big application delivery from last year, although the latter phase slipped (business, rather than project reasons). It was a bit of nightmare summer though as I worked a lot of long hours. I'm adamant that this summer will be very different.
Despite this success, there's not much else to add about work. Mainly because anything I write will probably get me into trouble as none of it is positive. Consider a veil drawn.
Current Obsessions
Flickr is my main obsession at the moment. I've been enjoying publishing the family photos, tagging, arranging and playing with them.
I've just finished reading The Baroque Cycle which totally absorbed me for several months. It's a fantastic series of books, and has prompted me to purchase several biographies as a result. I'm halfway through one on Robert Hooke, with Isaac Newton to follow. More on this in another blog entry I think.
I will note that its made me pine once again. Still can't afford to go back to Uni, but maybe there's a way that work and personal interests can be brought closer together.
Miscellanea
I'm speaking at XTech at the end of May and looking forward to catching up with folk in Amsterdam once again. I've organized a whole posse of friends to come over too -- we're meeting up after the conference for a long weekend in Amsterdam.
Big Chill tickets bought. As usual can't wait.
April 21, 2005
Ending HTTP Abuse
In Jon Udell's End HTTP Abuse piece he observes, as have many recently, that many of the popular web services don't do the right thing with GET and POST. In my paper for XTech this was one of the criteria I used to compare a number of different web services.
The complete list of reviewed services comprises: del.icio.us, flickr, bloglines, upcoming, 43things, musicbrainz, audioscrobbler/last.FM, and WebJay. The list originally included AllConsuming but the site has/is going through a complete rewrite and had to be dropped for now.
One of my aims for the paper was to help foster a community of practice among developers by comparing and contrasting the designs of each service along several different axes. I've attempted to highlight areas, like GET/POST handling, where the services fall short of meeting the REST architecture or just simply following the letter of the HTTP specification.
The complete list of review criteria includes: URI design; use of HTTP methods; correct use of status codes (another patchy area); authentication, and API tokens; use of hypermedia; data formats; exposure of personal data; and licensing of both the service and it's data. I think all of these criteria are important considerations when designing not only REST interfaces.
My conclusions about proper handling of GET/POST differ from Udell's. In the above piece he writes:
Why didn't Bloglines, Flickr, or del.icio.us enforce the POST restriction? I suspect it's because they wanted their APIs to have the broadest possible reach. And from a programmer's perspective, the simplest and easiest HTTP clients are those that use GET.
He then continues by exploring the ease of using GET versus POST on the client-side. I think the fault actually lies on the server-side. Specifically, with existing web applications frameworks.
In the Java world we've got Java Servlets. And what's the most commonly implemented method? It's not doGet its the generic service method. Thats the point at which the majority of frameworks hook into a Controller servlet to dispatch to server-side request handlers.
And yet, how many frameworks encourage or even allow the binding of handlers based on a combination of URL+method? In my experience the protocol independence anti-pattern kicks in at that point, and the request method is the last thing that a developer is encouraged to take into account. The end result are URLs that react identically to any request method. It might be an interesting experiment if Udell tried sending PUT, DELETE, HEAD requests to the same API calls.
This situation is often compounded by URL designs that are more RPC than REST in nature. E.g. /getPerson, /updatePerson rather than just /person. In the latter case you have to use the right request method to differentiate requests and respond appropriately.
I think a lot more attention needs to be paid to web application frameworks to address some of these issues. In the Java world even recent specifications like JavaServer Faces fall short in some fairly fundamental areas.
As Udell notes, after more than a decade we're still working out how best to use HTTP. And that has to translate into closer attention to our toolkits and, where necessary, ripping them out and replacing them with something better.
ISWC 2005 Submission
As I've alluded to in the past we've been exploring moving our content repository over to an RDF triple store.
It's turning out to be pretty massive, we've learnt a few things along the way, and no doubt have much more to learn as we continue with the project. Seemed worthwhile submitting a conference paper to share the experience. So here's what Priya, Katie, and myself have just submitted to ISWC2005:
The IngentaConnect website contains metadata from 17 million articles sourced from 20 thousand publications. The aim of the Metastore project is to build a flexible and scalable repository for the storage of this bibliographic metadata. The repository will replace several existing data stores and will act as a focal point for integration of a number of existing applications and future projects. Scalability, replication and robustness were important considerations in the repository design.
After introducing the benefits of using RDF as the data model for this repository, the paper will introduce the practical challenges involved in creating and managing a very large triple store. The repository contains over 200 million triples from a range of vocabularies including Dublin Core and PRISM. To our knowledge, this is the largest triple store of its type in existence.
The challenges faced range from schema design, initial data loading, query performance, and integration of the repository into existing applications.
The paper will introduce the solutions developed to meet these challenges with the goal of helping others looking to deploy a triple store within a commercial environment. The paper will also suggest some avenues for further research and development.
Won't hear whether the submission will be accepted until July, but expect to read more here over the coming months.
New SPARQL Specification
I'm very pleased to see the publication of the latest SPARQL specification.
It looked for a while as if FROM was going to be removed from the language, i.e. specifying the data set would be a protocol issue and not something supported in the query language. This seemed like a bad idea to me, not because of any deep technical issues, but more because I see a lot of benefit in having self-contained queries. Something that I can pass on to an expert for optimisation, or cut-and-paste into code or query tool, publish for others to use, etc.
Secondly I was originally concerned that there would be no ORDER BY; sorting seemed pretty essential to me. Apparently I wasn't the only one, and the DAWG have accepted sorting as a design objective. The new Building a Table of Contents use case also gave me cause to grin this morning.
I'm less enamoured of the new Turtle style syntax, much preferring the original bracketed triples which are easy to read IMO. I find the additional magic punctuation to be a real turn off. I've not had time to dig through the public archives to find out what motivated the change. No doubt I'll get used to it though.
But to end on a positive note, it's really great to see ORDER BY in the specification and progress continuing. Have printed out the spec and Dave's SPARQL reference for a little light reading so I can catch up with more of the detailed changes.
April 14, 2005
Who Should You Vote For?
I just filled this out as an idle exercise to see that the results would be: Who Should You Vote For?. I don't feel that any party represents my views especially well, but my expected outcome was Liberal Democrat. You can see the results for yourself:
 Labour 8 | |
Conservative -21  | |
| Liberal Democrat 34 | |
| UK Independence Party 25 | |
| Green 26 |
You should vote: Liberal Democrat
The LibDems take a strong stand against tax cuts and a strong one in favour of public services: they would make long-term residential care for the elderly free across the UK, and scrap university tuition fees. They are in favour of a ban on smoking in public places, but would relax laws on cannabis. They propose to change vehicle taxation to be based on usage rather than ownership.
Take the test at Who Should You Vote For
So there you go!
April 05, 2005
Bath Local Heroes
So I read about the Tentacle Man, the Red Man, the Grey Lady and the Purple Man, and tried to find a picture of the much missed Bath Blue Man, but couldn't find one. Anyone care to share?
His gimmick was to paint himself blue and stand immobile in an alcove next to the Roman Baths waiting for tourists to fling coins in his general direction. I actually preferred to see him idling in-between bouts of standing, still when he'd be enjoying a crafty roll-up. Many pretenders have tried to take his place (and his space come to think of it), but without success.
I did find this Local Heroes in Bath list though, which made me chuckle, especially entries like "Rolf Harris visits a bit". I'm slightly dubious about the assertion that Michael Jackson lives in Bath though. I may have to trot into town at the weekend to see if I can see Cheggers on the High Street, Lionel Blair in Boots, or maybe Seal in Sainsburys.
I'm doing slightly better than the author who wrote:
"Lived there for 21 years. I've never clapped eyes on a celeb. If you're a tourist p,raps you're more likely to look"
...as I did once see Anthony Stuart Head on the train. He had a brace of teenager girls travelling with him who I could only assume were "Slayers in Training".
Come to think of it, if you're a Bath resident you're perhaps more likely to spend your time tripping over tourists and forging a path through a sea of backpacks than looking for tourists.
1000 points to the first person to spot Rolf Harris on a bus tour, 500 points for any other celebrity, excluding Peter Gabriel who apparently "has been known to drive through town in his sports car" instead.
April 04, 2005
More Intermediary Patterns
Prompted by some contributions from Mark Pilgrim, I've just made another quick update to the intermediary patterns.
This expands on the number of Data patterns to include Page Context Reader and External Context Reader and the Action patterns to include Restyler, Blocker, and Rearranger.
Ryan Shaw is also looking at documenting his Greasemonkey script amazon2melvyl
using the patterns which is excellent. To help this I've clarified the Screen Scraper and Semantic Markup Reader patterns and also added the Link Scanner pattern. Scripts that search the current page for links seems a fairly common activity.
In Jon Udell's latest screencast: Content, services, and the yin-yang of intermediation you can see both the URL Parser and Link Scanner patterns in action. He demonstrates his Library Lookup Bookmarklet, which is a Button Press(*) URL Parser that generates a form. Udell also demonstrates the Library Lookup service as a Greasemonkey script, this is an example of an Event Driven Link Scanner which drops links into the page.
(*) Not happy with that name, can anyone suggest a better one?
April 01, 2005
Patterns of Intermediation Continued
Continuing yesterdays theme and after a quick bout of structured procrastination, I give you a first working draft: Patterns of Intermediation.
Little more than a shell-document, but I've included some named patterns to get the ball rolling.
I'm intending to evolve the descriptions, provide examples, etc so that the patterns conform basically to the Portland Form which seems suitably pithy.
Feel free to contribute content or patterns, contributions will be acknowledged of course. I'll be adding to this as I can get time.
Please use the patterns-of-intermediation tag when commenting.