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Unit 13: Extensible Markup Language

13.5 Transforming XML with XSLT Notes

Extensible Stylesheet Language Transformations (XSLT) is a language for transforming XML
documents into different XML, HTML, or any other format. For example, many web sites offer
several formats of their content.

HTML, printable HTML, and WML (Wireless Markup Language) are common. The easiest way
to present these multiple views of the same information is to maintain one form of the content
in XML and use XSLT to produce the HTML, printable HTML, and WML.
PHP’s XSLT support is still experimental at the time of writing, and the exact implementation
details may change from what is described here. However, this description should give you a
good foundation for how to use PHP’s XSLT functions, even if the implementation changes in
the future.
Three documents are involved in an XSLT transformation: the original XML document, the XSLT
document containing transformation rules, and the resulting document. The final document
does not have to be in XML. A common use of XSLT is to generate HTML from XML. To do an
XSLT transformation in PHP, you create an XSLT processor, give it some input to transform,
and then destroy the processor.
Create a processor with xslt_create( ):
$xslt = xslt_create( );
Process a file with xslt_process( ):

$result = xslt_process(xslt, xml, xsl [, result [, arguments [, parameters ]]]);
The xml and xsl parameters are filenames for the input XML and transformation XSL, respectively.
Specify a result filename to store the new document in a file, or omit it to have xslt_process( )
return the new document. The parameters option is an associative array of parameters to your
XSL, accessible through xsl:param name=”parameter_name”.
The arguments option is a roundabout way of working with XML or XSL stored in variables
rather than in files. Set xml or xsl to ‘arg:/foo’, and the value for /foo in the arguments associative
array will be used as the text for the XML or XSL document.

Given example is the XML document we are going to transform. It is in a similar format to
many of the news documents you find on the Web.

XML document
<?xml version=”1.0” ?>

<news xmlns:news=”http://example.org/backslash.dtd”>
<story>
<title>xy Publishes Programming PHP</title>
<url>http://example.org/abes.php?id=20020430/458566</url>
<time>2002-04-30 09:04:23</time>

<author>ABC</author>
</story> <story>
<title>Transforming XML with PHP Simplified</title>
<url>http://example.org/abes.php?id=20020430/458566</url>

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