How do I enable XSLT functions in PHP 5?

I'm wanting to print an xml file out as an HTML nested list using xslt, and as far as I know the code is correct, however I'm getting this error

Fatal error: Call to undefined function xslt_create()

Which I presume means the xslt functions havn't been enabled. How do I enable these functions within PHP? Is there a php file I need to include (like the way Javascript libraries work) or is it something more complicated? I'm hosted with MediaTemple.

Here's the php code I'm using:

        <?php 

    // Allocate a new XSLT processor 
    $xh = xslt_create(); 

    // Process the document, returning the result into the $result variable 
    $result = xslt_process($xh, 'armstrong.xml', 'familyToNestedList.xsl'); 
    if ($result) { 
        print "SUCCESS, sample.xml was transformed by sample.xsl into the \$result"; 
        print " variable, the \$result variable has the following contents\n<br>\n"; 
        print "<pre>\n"; 
        print $result; 
        print "</pre>\n"; 
    } 
    else { 
        print "Sorry, sample.xml could not be transformed by sample.xsl into"; 
        print "  the \$result variable the reason is that " . xslt_error($xh) .  
        print " and the error code is " . xslt_errno($xh); 
    } 

    xslt_free($xh); 

    ?>

Thanks in advance!

Solution

You have to compile PHP with the support for it and make sure to have all the required dependencies. Please see the corresponding chapters in the PHP Manual for XSLT.

From chapter Requirements

This extension requires the libxml PHP extension. This means that passing in --enable-libxml is also required, although this is implicitly accomplished because libxml is enabled by default. This extension uses Sablotron and expat, which can both be found at » http://freshmeat.net/projects/sablotron/. Binaries are provided as well as source. Enable by using the --with-xslt option with PHP 4.

From chapter Installation

On Unix, run configure with the --enable-xslt --with-xslt-sablot options. The Sablotron library should be installed somewhere your compiler can find it. Make sure you have the same libraries linked to the Sablotron library as those, which are linked with PHP. The configuration options: --with-expat-dir=DIR --with-iconv-dir=DIR are there to help you specify them. When asking for support, always mention these directives, and whether there are other versions of those libraries installed on your system somewhere. Naturally, provide all the version numbers.

The recommended extension for using XSL transformations with PHP5 is XSL. If all you need to do is transform two documents, as show in your example, consider this example from the PHP Manual:

$xml = new DOMDocument;
$xml->load('collection.xml');

$xsl = new DOMDocument;
$xsl->load('collection.xsl');

// Configure the transformer
$proc = new XSLTProcessor;
$proc->importStyleSheet($xsl); // attach the xsl rules

echo $proc->transformToXML($xml);

The transformToXML method will return the transformed document or FALSE, so you can keep the if/else from your code. In any case, it should be trivial to upgrade your code.