DOMNode::C14N

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

DOMNode::C14N — Canonizar nodos a una cadena

Descripción

public DOMNode::C14N(
    bool $exclusive = false,
    bool $withComments = false,
    ?array $xpath = null,
    ?array $nsPrefixes = null
): string|false

Canoniza nodos a una cadena

Parámetros

exclusive: Habilita el análisis exclusivo de los nodos que coincidan únicamente con el xpath o los prefijos de nombres de espacio proporcionados.
withComments: Conservar los comentarios en la salida.
xpath: Un array de xpaths por los que filtrar los nodos.
nsPrefixes: Un array de prefijos de nombres de espacio por los que filtrar los nodos.

Valores devueltos

Devuelve los nodos canonizados como cadenas o false en caso de error

Ver también

DOMNode::C14NFile() - Canonizar nodos a un fichero

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User Contributed Notes 3 notes

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Rijk ¶

11 years ago

When working with (malformed) HTML, you're probably better off using DOMDocument's saveHTML() method instead. C14N() will attempt to make your HTML valid XML, for example by converting <br> to <br></br>.

So instead of:
$html = $Node->C14N();

Use:
$html = $Node->ownerDocument->saveHTML( $Node );

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jorda at edpsciences dot org ¶

9 years ago

C14N() returns an empty string if the node is not included in the document tree:
<?php
$d = new DOMDocument('1.0');
$d->loadXML('<foo></foo>');
$n = $d->createElement('bar');
var_dump($n->C14N());
$d->documentElement->appendChild($n);
var_dump($n->C14N());
?>
output:
string(0) ""
string(11) "<bar></bar>"

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lordbaco ¶

8 years ago

[edit by nielsdos: This has been fixed starting in PHP 8.4]



Good to know:



<< Due to a known issue in XML canonicalization in PHP, processing large metadata files in SimpleSAMLphp takes a big amount of resources, with that amount growing approximately by the square of the number of entities in the metadata set >>

https://simplesamlphp.org/metaprocessing



<< The C14N() function appears to have a runtime that is O(N^2) (or possibly worse?) depending on input size, which means that it becomes very slow as the input grows. For example, an input with around 196000 nodes takes about 290 seconds, while an input with 486000 nodes takes 2200 seconds. >>

https://bugs.php.net/bug.php?id=53655



We had the same issue with a 4.1 MB XML (105k lines). The sample code of ticket  #53655 takes 1h36 minute to canonicalize it!

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