PHP 5.4.36 Released

DOMDocument::loadXML

(PHP 5)

DOMDocument::loadXML Load XML from a string

Descrierea

public mixed DOMDocument::loadXML ( string $source [, int $options = 0 ] )

Loads an XML document from a string.

Parametri

source

The string containing the XML.

options

Bitwise OR of the libxml option constants.

Valorile întoarse

Întoarce valoarea TRUE în cazul succesului sau FALSE în cazul eșecului. If called statically, returns a DOMDocument sau FALSE în cazul eșecului.

Erori/Excepții

If an empty string is passed as the source, a warning will be generated. This warning is not generated by libxml and cannot be handled using libxml's error handling functions.

Această metodă poate fi apelată în mod static, dar va emite o eroare E_STRICT.

Exemple

Example #1 Creating a Document

<?php
$doc 
= new DOMDocument();
$doc->loadXML('<root><node/></root>');
echo 
$doc->saveXML();
?>

Example #2 Static invocation of loadXML

<?php
// Issues an E_STRICT error
$doc DOMDocument::loadXML('<root><node/></root>');
echo 
$doc->saveXML();
?>

Vedeți de asemenea

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User Contributed Notes 11 notes

up
8
Gustavo L. Fabro
1 year ago
Always remember that with the default parameters this function doesn't handle well large files, i.e. if a text node is longer than 10Mb it can raise an exception stating:

DOMDocument::loadXML(): internal error Extra content at the end of the document in Entity

even though the XML is fine.

The cause is a definition in parserInternals.h of lixml:
#define XML_MAX_TEXT_LENGTH 10000000

To allow the function to process larger files, pass the LIBXML_PARSEHUGE as an option and it will work just fine:

$domDocument->loadXML($xml, LIBXML_PARSEHUGE);
up
2
shaoyu73 at gmail dot com
7 years ago
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.
up
2
jazzslider at hotmail dot com
7 years ago
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.
up
2
Stuart Grimshaw
7 years ago
Possible values for the options parameter can be found here:

http://us3.php.net/manual/en/ref.libxml.php#libxml.constants
up
2
Marc Liyanage
7 years ago
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.
up
2
Gavin Sinai gsinai at gmx dot net
8 years ago
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.
up
0
remacg
5 years ago
Instead of doing this:

<?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();
?>

simply use:

loadHTML() rather than loadXML().
up
0
olalonde at NOSPAM dot gmail dot com
6 years ago
For some reason, when you set DOMDocument's property 'recover' to true, using '@' to mask errors thrown by loadXml() won't work.

Here's my workaround:

function maskErrors() {}
set_error_handler('maskErrors');
$dom->loadXml($xml);
restore_error_handler();

You could also simply do this: error_reporting(0); and then set back error_reporting to its original state.
up
0
mp at webfactory dot de
8 years ago
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.
up
0
earth at anonymous dot com
8 years ago
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.
up
-1
szalma dot laszlo at zengo dot eu
5 years ago
Loading from a string works fine without the <?xml version="1.0" encoding="utf-8"?> header, but in this case the xmlEncoding won't be set, and this makes the utf-8 characters (international, and special characters) to be encoded as hexa entities when saved with saveXML()!
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