DOMDocument::registerNodeClass
(PHP 5 >= 5.2.0, PHP 7, PHP 8)
DOMDocument::registerNodeClass — Register extended class used to create base node type
说明
This method allows you to register your own extended DOM class to be used afterward by the PHP DOM extension.
This method is not part of the DOM standard.
The constructor of the objects of the registered node classes is not called.
参数
baseClass
-
The DOM class that you want to extend. You can find a list of these classes in the chapter introduction.
extendedClass
-
Your extended class name. If
null
is provided, any previously registered class extendingbaseClass
will be removed.
返回值
总是返回 true
。
更新日志
版本 | 说明 |
---|---|
8.4.0 | DOMDocument::registerNodeClass() now has a tentative return of true. |
示例
示例 #1 Adding a new method to DOMElement to ease our code
<?php
class myElement extends DOMElement {
function appendElement($name) {
return $this->appendChild(new myElement($name));
}
}
class myDocument extends DOMDocument {
function setRoot($name) {
return $this->appendChild(new myElement($name));
}
}
$doc = new myDocument();
$doc->registerNodeClass('DOMElement', 'myElement');
// From now on, adding an element to another costs only one method call !
$root = $doc->setRoot('root');
$child = $root->appendElement('child');
$child->setAttribute('foo', 'bar');
echo $doc->saveXML();
?>
以上示例会输出:
<?xml version="1.0"?> <root><child foo="bar"/></root>
示例 #2 Retrieving elements as custom class
<?php
class myElement extends DOMElement {
public function __toString() {
return $this->nodeValue;
}
}
$doc = new DOMDocument;
$doc->loadXML("<root><element><child>text in child</child></element></root>");
$doc->registerNodeClass("DOMElement", "myElement");
$element = $doc->getElementsByTagName("child")->item(0);
var_dump(get_class($element));
// And take advantage of the __toString method..
echo $element;
?>
以上示例会输出:
string(9) "myElement" text in child
示例 #3 Retrieving owner document
When instantiating a custom DOMDocument the ownerDocument property will refer to the instantiated class. However, if all references to that class are removed, it will be destroyed and new DOMDocument will be created instead. For that reason you might use DOMDocument::registerNodeClass() with DOMDocument
<?php
class MyDOMDocument extends DOMDocument {
}
class MyOtherDOMDocument extends DOMDocument {
}
// Create MyDOMDocument with some XML
$doc = new MyDOMDocument;
$doc->loadXML("<root><element><child>text in child</child></element></root>");
$child = $doc->getElementsByTagName("child")->item(0);
// The current owner of the node is MyDOMDocument
var_dump(get_class($child->ownerDocument));
// MyDOMDocument is destroyed
unset($doc);
// And new DOMDocument instance is created
var_dump(get_class($child->ownerDocument));
// Import a node from MyDOMDocument
$newdoc = new MyOtherDOMDocument;
$child = $newdoc->importNode($child);
// Register custom DOMDocument
$newdoc->registerNodeClass("DOMDocument", "MyOtherDOMDocument");
var_dump(get_class($child->ownerDocument));
unset($doc);
// New MyOtherDOMDocument is created
var_dump(get_class($child->ownerDocument));
?>
以上示例会输出:
string(13) "MyDOMDocument" string(11) "DOMDocument" string(18) "MyOtherDOMDocument" string(18) "MyOtherDOMDocument"
示例 #4 Custom objects are transient
Objects of the registered node classes are transient, i.e. they are destroyed when they are no longer referenced from PHP code, and recreated when being retrieved again. That implies that custom property values will be lost after recreation.
<?php
class MyDOMElement extends DOMElement
{
public $myProp = 'default value';
}
$doc = new DOMDocument();
$doc->registerNodeClass('DOMElement', 'MyDOMElement');
$node = $doc->createElement('a');
$node->myProp = 'modified value';
$doc->appendChild($node);
echo $doc->childNodes[0]->myProp, PHP_EOL;
unset($node);
echo $doc->childNodes[0]->myProp, PHP_EOL;
?>
以上示例会输出:
modified value default value
用户贡献的备注 2 notes
Creating innerHTML and outerHTML
<?php
class DOMHTMLElement extends DOMElement
{
function __construct() { parent::__construct();}
public function innerHTML()
{
$doc = new DOMDocument();
foreach ($this->childNodes as $child){
$doc->appendChild($doc->importNode($child, true));
}
$content = $doc->saveHTML();
return $content;
}
public function outerHTML()
{
$doc = new DOMDocument();
$doc->appendChild($doc->importNode($this, true));
$content = $doc->saveHTML();
return $content;
}
}
$dom = DOMDocument::loadHTMLFile($file);
$dom->registerNodeClass('DOMElement','DOMHTMLElement');
if($dom)
{
$xpath = new DOMXpath($dom);
$regions = $xpath->query("//*[contains(@class, 'editable')]");
$content = '';
foreach($regions as $region){
$content .= $region->outerHTML();
}
return $content;
}else{
throw new Exception('Cannot parse HTML. Please verify the syntax is correct.');
}
?>
Note than save and saveXML are not affected by __toString().
备份地址:http://www.lvesu.com/blog/php/domdocument.registernodeclass.php