DOMNode::C14N

(PHP 5 >= 5.2.0, PHP 7)

DOMNode::C14Nノードを文字列に正規化する

説明

public string DOMNode::C14N ([ bool $exclusive [, bool $with_comments [, array $xpath [, array $ns_prefixes ]]]] )

ノードを文字列に正規化します。

パラメータ

exclusive

指定した xpath あるいは名前空間プレフィックスにマッチするノードだけを対象としたパースを有効にする。

with_comments

コメントを残して出力する。

xpath

ノードを絞り込むための xpath の配列。

ns_prefixes

ノードを絞り込むための名前空間プレフィックスの配列。

返り値

正規化したノードを文字列で返します。 失敗した場合に FALSE を返します

参考

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User Contributed Notes 3 notes

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14
Rijk
4 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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6
jorda at edpsciences dot org
2 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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1
lordbaco
1 year ago
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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