In my last article I covered the use of the expat functions available to PHP for parsing XML documents using the SAX method. The sample code was a class that read the XML document and generated the HTML to present the data in a nice table. This example was far from perfect due to the fact that the presentation of the data was not separate from the class code that had to parse the XML document. This meant that a slight modification to the HTML generated by the class could break the actual parsing functionality of the class.

This is not the ideal way of doing things in a production environment, hence the purpose of this article in explaining how to parse XML documents using XSLT (eXtensible Stylesheet Language Transformations). XSLT is a language for transforming XML documents into other XML documents or HTML documents. I will not discuss XML, XSL or XSLT syntax in this article, for a good introduction to these please refer to the links at the end of this article.The focus of this article is on how to transform XML documents with XSLT using the Sablotron XSLT processor.

Sablotron is the result of a project to develop a fast, reliable, compact and portable XSLT processor conforming to the W3C specification. It currently supports Linux, Windows NT and, beginning with version 0.42, Solaris. It requires the expat XML Parser. In addition to these pieces of software the PHP4 sablotron extension wrapper is required to build an extension module that you can load with the PHP4 parser to give you access to the Sablotron API. This may sound a bit complex but it's really not and the result is well worth the power that these functions will provide you with. Some links to instructions on how to do all this are provided at the end of the article.

To demonstrate the use of these functions I have written an XSLT class that takes XML and XSL wether it be in the format of a file, a URL or a String and performs the transform. I use this class to to read an XML document from the web (the Slashdot news!) and transform it into an HTML page using an XSLT document on the local file system.
I'll do my best to explain how I've done this and welcome questions in the followup section, so here goes nothing ! ...