Using a sad old cliché I hereby declare the train wreck that is xsi:type should be considered harmful:

1. First of all it assumes the receiver has a W3C XML Schema. Wrong! Schemas are just one of a number of different ways I might have used to describe the XML. You might be using a description I gave you in RelaxNG, on the back of an envelope, whatever. You might have constructed your own model. I don’t care so long as you send me the right elements, attributes and content. You know, the right “stuff”.
2. Sticking the Schema abstract type into a message is at best verbose, worst expects me to understand how you’re thinking about the data. I don’t care. Really. Just send me the “stuff”.
3. Whilst Schema is wishy-washy about things such as where a schema is located, here we don’t have a hint. No, it’s an assertion. You will obey xsi:type.
4. It encourages people to want to switch “types” on the fly. Yikes, that’s a manifesto to Monkey Patch (via Sam)
5. It’s intrinsically insecure, consider eviltude such as <getTime xsi:type="FireNuclearMissiles">.
6. Dynamic languages don’t need it, OK, maybe it’s useful when a repeated list has only one item, but otherwise Duck Typing is what I like and if I want to process my accountNo as an integer or a string, I’d rather keep that choice under my Kimono. thank you very much!
7. It doesn’t work with many existing static language tools, for example a number of JAXB2 implementations take an xs:anyURI, generate a Java string, but then bounce xsi:type="xs:anyURI". Yes really. I may cry.
8. It doesn’t help the versioning story. Sorry. It just doesn’t.

So don’t touch it. It’s eviil!

Technorati Tags: databinding, Schema, w3c, XML

So We’ve published a Last Call Working Draft of Basic XML Schema Patterns for Databinding Version 1.0 and the First Public Working Draft of Advanced Patterns. Yay! The patterns in Basic are, um, very Basic, but we’ve a nice approach for our testsuite to prove they work with implementations (details shortly). The Advanced patterns are fairly limited in scope, but we’ve a mechanism to detect patterns in Schema and WSDL documents from the wild we hope to use to drive that document forward. You can contribute by making comments, sending examples, submitting implementation reports and pointing us at your schemas.

Technorati Tags: databinding, w3c, XML

I wonder how long before I get bored with Twitter..

Dinard, November 2006 is a set of photos from last week’s W3C WSDL Interop Workshop. As Jonathan says we worked hard, ate well and even managed to play a little werewolf. My only disappointment was not to have contributed as much to the WSDL testing as I’d have liked (I was preoccupied with preparing the Databinding Last Call drafts) and the complete absence of French Onion Sellers.

Technorati Tags: flickr, photography, w3c, wsdl

So Planet Interwingly just saved me 120CHF! I was just thinking about not downloading
ISO/IEC 19757-3:2006 (Schematron) whilst mumbling about “mean bu99ers” under my breath when up popped Rick’s Announcement. There’s a whole raft of specs free for the asking. So you can get owt for nowt!

Technorati Tags: standards, ISO, XML

So we now have interopalliance.org:

Making Technologies Work Better Together for Customers
The Interop Vendor Alliance is a community of software and hardware vendors working together to enhance interoperability with Microsoft systems.

Which is nice because who better knows what customers want better than vendor-pies and silicon shifters? At first glance this looks like a marketing operation designed to sell customers the illusion of Web services interoperability except they explicitly don’t want customers involved, not even to bash on a plastic steering wheel whilst the drive train is connected to a smoke filled board room next door.

So what’s not to like? Surely like motherhood and apple pie, any effort to increase Interop surely has to be a good thing? Firstly getting everybody to interop with Microsoft is simply one to many, when interop is all about are many to many. What happens when there is an issue? Will we ever get to find out - I somehow doubt it! And who is going to fix their stuff, the “one” or the “many”.

I’m quite despondent we have yet another organisation to position and track, but at least I’m unlikely to be able to attend this country club. What we need now is an organisation to manage the interoperability between the interoperability organisations.

Then there are the vendors listed as “founding members”. I used to think there was only one standardisation initiative IBM had spurned, I suddenly feel a lot less special ;-)

But most of all I’m baffled why Microsoft are leading this given they already have the workshop process for Web services and that’s a game they can stop any time they want their ball back. Maybe this results from a little arm twisting?

Technorati Tags: interoperability, WebServices, WS-I

Kewl! I note England is finally on Yahoo! maps, and therefore available in flickr’s mapping. Time to revisit some of my geotagging photos and hacks, methinks.

Technorati Tags: flickr, geotagging, maps, Yahoo!

I’d love to be able to remain ignorant of US politics, but it’s hard to ignore a large friendly dog in a small room, and although they have two parties which are identically useless (unlike here in the UK where we have three main parties which are um identically useless), Bush and his posse are without question a morally bankrupt bunch of witless feckers. So it’s nice to see them get a little slap. Wonder if it’ll make any difference.

Technorati Tags: politics

So Internet Explorer 7 rejects DTDs:

Feeds that reference a DTD are not supported by the RSS Platform. A DTD is used to help XML parsers with validation of the document. However, DTD validation is a potential source of security issues for XML parsers, and validation is not required for feeds to work correctly in aggregators.

This is by no means news from Microsoft possibly with good cause. The WS-I Basic Profile disallows DTDs in SOAP messages, and just like SOAP many see RSS as a serialisation spewed out by tools and not a document lovingly crafted by humans, to which I say “feh”. Still it’s likely to take many others by surprise.

Coincidentally I’m currently trying to work out how well supported DTDs are by databinding implementations, and thus far they seem OK-ish, but I do wonder for how much longer. I guess we are just observing a defacto XML 2.0 emerging, which is OK, but not before we have a standard replacement for entities, something like xmlchar or EDML might be good enough if only everyone could have agreed upon them six years ago. You know it’s much easier to chop things off than add new stuff in later.

Technorati Tags: XML