Error handling with libxml error handling functions

    libxml offers a number of functions for handling errors, which can be employed to capture and deal with errors in XSLT processing.

    Example #1 fruits.xml

    A valid XML file.

    <fruits> <fruit>Apple</fruit> <fruit>Banana</fruit> <fruit>Cherry</fruit> </fruits>

    Example #2 fruits.xsl

    Contains an invalid select expression.

    <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output method="html" encoding="utf-8" indent="no"/> <xsl:template match="fruits"> <ul> <xsl:apply-templates/> </ul> </xsl:template> <xsl:template match="fruit"> <li><xsl:value-of select="THIS IS A DELIBERATE ERROR!"/></li> </xsl:template> </xsl:stylesheet>

    Example #3 Collating and printing errors

    The example below captures and displays libxml errors raised when calling XSLTProcessor::importStyleSheet() with a stylesheet containing an error.

    <?php

    $xmldoc     = new DOMDocument();
    $xsldoc = new DOMDocument();
    $xsl = new XSLTProcessor();

    $xmldoc->loadXML('fruits.xml');
    $xsldoc->loadXML('fruits.xsl');

    libxml_use_internal_errors(true);
    $result = $xsl->importStyleSheet($xsldoc);
    if (!    $result) {
    foreach (    libxml_get_errors() as $error) {
    echo     "Libxml error: {$error->message}\n";
    }
    }
    libxml_use_internal_errors(false);

    if (    $result) {
    echo     $xsl->transformToXML($xmldoc);
    }

    ?>

    The above example will output something similar to:

     Libxml error: Invalid expression Libxml error: compilation error: file fruits.xsl line 9 element value-of Libxml error: xsl:value-of : could not compile select expression 'THIS IS A DELIBERATE ERROR!'
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