Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

LIBXML_BIGLINES (int): Allows line numbers greater than 65535 to be reported correctly.
Note:
Only available as of PHP 7.0.0 with Libxml >= 2.9.0
LIBXML_COMPACT (int): Activate small nodes allocation optimization. This may speed up your application without needing to change the code.
Note:
Only available in Libxml >= 2.6.21
LIBXML_DTDATTR (int): Default DTD attributes
LIBXML_DTDLOAD (int): Load the external subset
LIBXML_DTDVALID (int): Validate with the DTD
Caution
Enabling validating the DTD may facilitate XML External Entity (XXE) attacks.
LIBXML_HTML_NOIMPLIED (int): Sets HTML_PARSE_NOIMPLIED flag, which turns off the automatic adding of implied html/body... elements.
Note:
Only available in Libxml >= 2.7.7 (as of PHP >= 5.4.0)
LIBXML_HTML_NODEFDTD (int): Sets HTML_PARSE_NODEFDTD flag, which prevents a default doctype being added when one is not found.
Note:
Only available in Libxml >= 2.7.8 (as of PHP >= 5.4.0)
LIBXML_LOADED_VERSION (string): Version of libxml's core parser module.
LIBXML_NOBLANKS (int): Remove blank nodes
LIBXML_NOCDATA (int): Merge CDATA as text nodes
LIBXML_NOEMPTYTAG (int): Expand empty tags (e.g. <br/> to <br></br>)
Note:
This option is currently just available in the DOMDocument::save and DOMDocument::saveXML functions.
LIBXML_NOENT (int): Substitute entities
Caution
Enabling entity substitution may facilitate XML External Entity (XXE) attacks.
LIBXML_NOERROR (int): Suppress error reports
LIBXML_NONET (int): Disable network access when loading documents
LIBXML_NOWARNING (int): Suppress warning reports
LIBXML_NOXMLDECL (int): Drop the XML declaration when saving a document
Note:
Only available in Libxml >= 2.6.21
LIBXML_NSCLEAN (int): Remove redundant namespace declarations
LIBXML_PARSEHUGE (int): Sets XML_PARSE_HUGE flag, which relaxes any hardcoded limit from the parser. This affects limits like maximum depth of a document or the entity recursion, as well as limits of the size of text nodes.
Note:
Only available in Libxml >= 2.7.0 (as of PHP >= 5.3.2 and PHP >= 5.2.12)
LIBXML_PEDANTIC (int): Sets XML_PARSE_PEDANTIC flag, which enables pedantic error reporting.
Note:
Available as of PHP >= 5.4.0
LIBXML_XINCLUDE (int): Implement XInclude substitution
LIBXML_ERR_ERROR (int): A recoverable error
LIBXML_ERR_FATAL (int): A fatal error
LIBXML_ERR_NONE (int): No errors
LIBXML_ERR_WARNING (int): A simple warning
LIBXML_VERSION (int): libxml version like 20605 or 20617
LIBXML_DOTTED_VERSION (string): libxml version like 2.6.5 or 2.6.17
LIBXML_SCHEMA_CREATE (int): Create default/fixed value nodes during XSD schema validation
Note:
Only available in Libxml >= 2.6.14 (as of PHP >= 5.5.2)

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User Contributed Notes 5 notes

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@oneseventeen ¶

13 years ago

When inserting XML DOM Elements inside existing XML DOM Elements that I loaded from an XML file using the following code, none of my new elements were formatted correctly, they just showed up on one line:

<?php 
$dom = DOMDocument::load('file.xml'); 
$dom->formatOutput = true;
//$dom->add some new elements with child nodes somewhere inside the loaded XML using insertBefore();
$dom->saveXML();
//output: everything looks normal but the new nodes are all on one line.
?>

I found I could pass LIBXML_NOBLANKS to the load method and it would reformat the whole document, including my added stuff:
<?php 
$dom = DOMDocument::load('file.xml', LIBXML_NOBLANKS); 
$dom->formatOutput = true;
//$dom->add some new elements with child nodes somewhere inside the loaded XML using insertBefore();
$dom->saveXML();
//output: everything looks newly formatted, including new nodes
?>

Hope this helps, took me hours of trial and error to figure this out!

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siraic at gmail dot com ¶

3 years ago

The name of the constant LIBXML_NOENT is very misleading. Adding this flag actually causes the parser to load and insert the external entities. Omitting it leaves the tags untouched, which is probably what you want.

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vetalstar at mail dot ru ¶

6 years ago

LIBXML_DOTTED_VERSION option doesn't work.
libxml version: 2.9.4

<?php

echo LIBXML_DOTTED_VERSION;
$xml = new SimpleXMLElement('<fasa_request id="1234567"/>', LIBXML_NOXMLDECL);

?>

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Ismael Miguel ¶

1 year ago

If you want to save without the XML declaration, and LIBXML_NOXMLDECL doesn't work for you, you can just do this:

<?php
$doc = new \DOMDocument('1.0', 'UTF-8');
$doc->loadXML($xml, LIBXML_*);

echo $doc->saveXML($doc->firstElementChild);
?>

This will output the XML without the XML declaration and without using the flag.
You also don't need to do fiddly replacements and pray that it works.

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zachatwork at gmail dot com ¶

14 years ago

Note: The LIBXML_NOXMLDECL constant is defined in this library but is not supported by DOMDocument (yet).

See also: http://bugs.php.net/bug.php?id=47137

<?php

print "PHP_VERSION:      ".PHP_VERSION."\n";
print "LIBXML_VERSION:   ".LIBXML_VERSION."\n";
print "LIBXML_NOXMLDECL: ".LIBXML_NOXMLDECL."\n";

$dom = new DomDocument();
$dom->loadXML("<foo />");

# This should work but doesn't.

print "DOMDocument doesn't honor LIBXML_NOXMLDECL:\n";
print $dom->saveXML(null,LIBXML_NOXMLDECL);

# This works, and will still work after the above is fixed.

print "Forwards compatible workaround:\n";
$lines = explode("\n", $dom->saveXML(null, LIBXML_NOXMLDECL), 2);
if(!preg_match('/^\<\?xml/', $lines[0]))
    print $lines[0];
print $lines[1];

?>

PHP_VERSION:      5.3.1-0.dotdeb.1
LIBXML_VERSION:   20632
LIBXML_NOXMLDECL: 2
DOMDocument doesn't honor LIBXML_NOXMLDECL:
<?xml version="1.0"?>
<foo/>
Forwards compatible workaround:
<foo/>

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