XSD

The main purpose of the XSD is for us to use in validating the XML directive documents we send to Apple. A secondary purpose is for us to see what's possible for us to send to Apple -- in a "this XSD is worth a thousand words of documentation" kind of way. 🙂 According to Duncan, iTunes U will not yet reject invalid directive documents outright, but there will come a time when a document will only be accepted if the XSD validates it.

It's like the W3C validators ... you tell them that you have a webpage someplace, they scan it and tell you that your page is "XHTML 1.0 Strict" ... so you know you should be cool. Now you can put that "XHTML 1.0 Strict" DTD line in your document and badge the webpage. 🙂

Pretty much every scripting/programming language gives you some way to use the XSD to validate the XML you create ...

Java:

http://www.theserverside.com/discussions/thread.tss?thread_id=37771

Python:

http://codespeak.net/lxml/validation.html

Perl:

http://search.cpan.org/~samtregar/XML-Validator-Schema-1.08/Schema.pm

Ruby (kind of circuitous, but should work):

http://codeidol.com/other/rubyckbk/XML-and-HTML/Validating-an-XML-Document/

C# (and .NET):

http://support.microsoft.com/kb/318504

And my favorite, Cocoa:

http://developer.apple.com/documentation/Cocoa/Reference/Foundation/Classes/NSXM LDocumentClass/Reference/Reference.html#//apple_ref/doc/cref/NSXMLDocumentValidate