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DOMDocument->loadXML()

Stuart Grimshaw
26-Jun-2007 01:57


Possible values for the options parameter can be found here:



http://us3.php.net/manual/en/ref.libxml.php#libxml.constants

Marc Liyanage
18-Jun-2007 07:08


The documentation states that loadXML can be called statically, but this is misleading. This feature seems to be a special case hack and its use seems to be discouraged according to http://bugs.php.net/bug.php?id=41398.



Calling the method statically will fail with an error if the code runs with E_STRICT error reporting enabled.



The documentation should be changed to make it clear that a static call is against recommended practice and won't work with E_STRICT.

gabriel dot birke at web dot de
03-May-2007 08:44


If you want to preserve greater-than and lower-than signs inside CDATA sections with XSL processing you have to use the LIBXML_NOCDATA option:



Given this XSL:

<?xml version="1.0" encoding="UTF-8"?>

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >

<xsl:output omit-xml-declaration="yes" />

<xsl:template match="/">

<script type="text/javascript">

<xsl:text disable-output-escaping="yes">

// Decorative Brackets: 

<![CDATA[// <<<<>>>> ]]>

</xsl:text>

</script>

</xsl:template>

</xsl:stylesheet>



and this PHP:



<?php



$xml = new DOMDocument;

$xml->load('dummy.xml');



$xsl1 = new DOMDocument;

$xsl1->load('scripttest.xsl');



$xsl2 = new DOMDocument;

$xsl2->load('scripttest.xsl', LIBXML_NOCDATA);



$proc = new XSLTProcessor;



echo "Normal Load:\n";

$proc->importStyleSheet($xsl1); 

echo $proc->transformToXML($xml);



echo "LIBXML_NOCDATA Load:\n";

$proc->importStyleSheet($xsl2); 

echo $proc->transformToXML($xml);



?> 



You get the following output:

Normal Load:

<script type="text/javascript">

// Decorative Brackets: 

// &lt;&lt;&lt;&lt;&gt;&gt;&gt;&gt; 

</script>

LIBXML_NOCDATA Load:

<script type="text/javascript">

// Decorative Brackets: 

// <<<<>>>> 

</script>

jazzslider at hotmail dot com
30-Apr-2007 01:14


When using loadXML() to parse a string that contains entity references (e.g., &nbsp;), be sure that those entity references are properly declared through the use of a DOCTYPE declaration; otherwise, loadXML() will not be able to interpret the string.



Example:

<?php

$str = <<<XML

<?xml version="1.0" encoding="iso-8859-1"?>

<div>This&nbsp;is a non-breaking space.</div>

XML;



$dd1 = new DOMDocument();

$dd1->loadXML($str);



echo $dd1->saveXML();

?>



Given the above code, PHP will issue a Warning about the entity 'nbsp' not being properly declared.  Also, the call to saveXML() will return nothing but a trimmed-down version of the original processing instruction...everything else is gone, and all because of the undeclared entity.



Instead, explicitly declare the entity first:

<?php

$str = <<<XML

<?xml version="1.0" encoding="iso-8859-1"?>

<!DOCTYPE root [

<!ENTITY nbsp "&#160;">

]>

<div>This&nbsp;is a non-breaking space.</div>

XML;



$dd2 = new DOMDocument();

$dd2->loadXML($str);



echo $dd2->saveXML();

?>



Since the 'nbsp' entity is defined in the DOCTYPE, PHP no longer issues that Warning; the string is now well-formed, and loadXML() understands it perfectly.



You can also use references to external DTDs in the same way (e.g., <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"

"http://www.w3.org/TR/html4/strict.dtd">), which is particularly important if you need to do this for many different documents with many different possible entities.



Also, as a sidenote...entity references created by createEntityReference() do not need this kind of explicit declaration.

shaoyu73 at gmail dot com
15-Mar-2007 09:53


earth at anonymous dot com,



preserveWhiteSpace property needs to be set to false for formatOutput to work properly, for some reason.



$dom = new DOMDocument;

$dom->preserveWhiteSpace = false;

$dom->loadXML($xmlStr);

...

$element->appendChild(...);

...

$dom->formatOutput = true;

$xmlStr = $dom->saveXML();

echo $xmlStr;



This would format the output nicely.

Gavin Sinai gsinai at gmx dot net
30-Aug-2006 07:34


loadXml reports an error instead of throwing an exception when the xml is not well formed. This is annoying if you are trying to to loadXml() in a try...catch statement. Apparently its a feature, not a bug, because this conforms to a spefication. 



If you want to catch an exception instead of generating a report, you could do something like



<?php

function HandleXmlError($errno, $errstr, $errfile, $errline)

{

    if ($errno==E_WARNING && (substr_count($errstr,"DOMDocument::loadXML()")>0))

    {

        throw new DOMException($errstr);

    }

    else 

        return false;

}



function XmlLoader($strXml)

{

    set_error_handler('HandleXmlError');

    $dom = new DOMDocument();

    $dom->loadXml($strXml);    

    restore_error_handler();

    return $dom;

 }



?>



Returning false in function HandleXmlError() causes a fallback to the default error handler.

mp at webfactory dot de
08-Aug-2006 08:26


While loadXML() expects its input to have a leading XML processing instruction to deduce the encoding used, there's no such concept in (non-XML) HTML documents. Thus, the libxml library underlying the DOM functions peeks at the <META> tags to figure out the encoding used.



See http://xmlsoft.org/encoding.html.

earth at anonymous dot com
12-Apr-2006 02:28


Note that loadXML crops off beginning and trailing whitespace and linebreaks.



When using loadXML and appendChild to add a chunk of XML to an existing document, you may want to force a linebreak between the end of the XML chunk and the next line (usually a close tag) in the output file:



$childDocument = new DOMDocument;

$childDocument>preserveWhiteSpace = true;

$childDocument->loadXML(..XML-Chunk..);

$mNewNode = $mainDOcument->importNode($childDocument->documentElement, true);

$ParentNode->appendChild($mNewNode);

$ParentNode->appendChild($mainDocument->createTextNode("\\n  ");



Although it is said that DOM should not be used to make 'pretty' XML output, it is something I struggled with to get something that was readable for testing.  Another solution is to use the createDocumentFragment()->appendXML(..XML-Chunk..) instead, which seems not to trim off linebreaks like DOMDocument->loadXML() does.

primaryspace at hotmail dot com
09-Aug-2005 01:42


This method replaces any existing document tree already in the object with the document tree contained in the source argument.

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DOMDocument->loadXML()

Описание

Список параметров

Возвращаемые значения

Примеры

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