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
    Caution

    Enabling loading of DTD attributes will enable fetching of external entities. The LIBXML_NO_XXE constant can be used to prevent this (only available in Libxml >= 2.13.0, as of PHP 8.4.0).

    LIBXML_DTDLOAD (int)
    Load the external subset
    Caution

    Enabling loading of external subsets will enable fetching of external entities. The LIBXML_NO_XXE constant can be used to prevent this (only available in Libxml >= 2.13.0, as of PHP 8.4.0).

    LIBXML_DTDVALID (int)
    Validate with the DTD
    Caution

    Enabling validating the DTD may facilitate XML External Entity (XXE) attacks. The LIBXML_NO_XXE constant can be used to prevent this (only available in Libxml >= 2.13.0, as of PHP 8.4.0).

    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_NO_XXE (int)
    Disables XML External Entities (XXE) when performing entity substitution

    Note:

    Only available in Libxml >= 2.13.0, as of PHP 8.4.0

    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_RECOVER (int)
    Enables recovery mode when parsing a document.

    Note:

    Only available as of PHP 8.4.0

    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

    up
    10
    @oneseventeen
    14 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();$dom->saveXML();//output: everything looks newly formatted, including new nodes?>Hope this helps, took me hours of trial and error to figure this out!
    up
    2
    siraic at gmail dot com
    4 years ago
    The name of the constant LIBXML_NOENT is very misleading. Adding this flag actually causes the parser to load and insert the external entities. Omitting it leaves the tags untouched, which is probably what you want.
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    2
    vetalstar at mail dot ru
    7 years ago
    LIBXML_DOTTED_VERSION option doesn't work.libxml version: 2.9.4<?phpecho LIBXML_DOTTED_VERSION;$xml = new SimpleXMLElement('<fasa_request id="1234567"/>', LIBXML_NOXMLDECL);?>
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    0
    Ismael Miguel
    2 years 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.
    up
    0
    zachatwork at gmail dot com
    15 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<?phpprint "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.1LIBXML_VERSION:   20632LIBXML_NOXMLDECL: 2DOMDocument doesn't honor LIBXML_NOXMLDECL:<?xml version="1.0"?><foo/>Forwards compatible workaround:<foo/>
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