justinpatrin at php dot net:
> To get a proper DOM document (which you need to do most things) you need...
No you don't. Just do:
<?php
$dom = dom_import_simplexml($xml)->ownerDocument;
?>
(PHP 5, PHP 7, PHP 8)
dom_import_simplexml — Gets a DOMElement object from a SimpleXMLElement object
This function takes the given attribute or element node (a
SimpleXMLElement instance) and creates a
DOMAttr or DOMElement node, repectively.
The new DOMNode refers to the same underlying XML node
as the SimpleXMLElement.
The DOMAttr or DOMElement.
| 版本 | 说明 |
|---|---|
| 8.0.0 |
This function no longer returns null on failure.
|
示例 #1 Import SimpleXML into DOM with dom_import_simplexml()
<?php
$sxe = simplexml_load_string('<books><book><title>blah</title></book></books>');
if ($sxe === false) {
echo 'Error while parsing the document';
exit;
}
$dom_sxe = dom_import_simplexml($sxe);
if (!$dom_sxe) {
echo 'Error while converting XML';
exit;
}
$dom = new DOMDocument('1.0');
$dom_sxe = $dom->importNode($dom_sxe, true);
$dom_sxe = $dom->appendChild($dom_sxe);
echo $dom->saveXML();
?>以上示例会输出：
<?xml version="1.0"?> <books><book><title>blah</title></book></books>
示例 #2 Import SimpleXML into DOM and modify SimpleXML through DOM
Error handling omitted for brevity.
<?php
$sxe = simplexml_load_string('<books><book><title>blah</title></book></books>');
$elt = dom_import_simplexml($sxe);
$elt->setAttribute("foo", "bar");
echo $sxe->asXML();
?>以上示例会输出：
<?xml version="1.0"?> <books foo="bar"><book><title>blah</title></book></books>
justinpatrin at php dot net:
> To get a proper DOM document (which you need to do most things) you need...
No you don't. Just do:
<?php
$dom = dom_import_simplexml($xml)->ownerDocument;
?>SimpleXML is an 'Object Mapping XML API'. It is not DOM, per se. SimpleXML converts the XML elements into PHP's native data types.
The dom_import_simplexml and simplexml_import_dom functions do *not* create separate copies of the original object. You are free to use the methods of either or both interchangeably, since the underlying instance is the same.
<?php
// initialize a simplexml object
$sxe = simplexml_load_string('<root/>');
// get a dom interface on the simplexml object
$dom = dom_import_simplexml($sxe);
// dom adds a new element under the root
$element = $dom->appendChild(new DOMElement('dom_element'));
// dom adds an attribute on the new element
$element->setAttribute('creator', 'dom');
// simplexml adds an attribute on the dom element
$sxe->dom_element['sxe_attribute'] = 'added by simplexml';
// simplexml adds a new element under the root
$element = $sxe->addChild('sxe_element');
// simplexml adds an attribute on the new element
$element['creator'] = 'simplexml';
// dom finds the simplexml element (via DOMNodeList->index)
$element = $dom->getElementsByTagName('sxe_element')->item(0);
// dom adds an attribute on the simplexml element
$element->setAttribute('dom_attribute', 'added by dom');
echo ('<pre>');
print_r($sxe);
echo ('</pre>');
?>
Outputs:
SimpleXMLElement Object
(
[dom_element] => SimpleXMLElement Object
(
[@attributes] => Array
(
[creator] => dom
[sxe_attribute] => added by simplexml
)
)
[sxe_element] => SimpleXMLElement Object
(
[@attributes] => Array
(
[creator] => simplexml
[dom_attribute] => added by dom
)
)
)
What this illustrates is that both interfaces are operating on the same underlying object instance. Also, when you dom_import_simplexml, you can create and add new elements without reference to an ownerDocument (or documentElement).
So passing a SimpleXMLElement to another method does not mean the recipient is limited to using SimpleXML methods.
Hey Presto! Your telescope has become a pair of binoculars!I've found that newer versions of PHP5 require some special syntax in order to properly convert between SimpleXML and DOM. It's not as easy as calling dom_import_simplexml() with a SimpleXML node. To get a proper DOM document (which you need to do most things) you need:
<?php
//$xml is a SimpleXML instance
$domnode = dom_import_simplexml($xml);
$dom = new DOMDocument();
$domnode = $dom->importNode($domnode, true);
$dom->appendChild($domnode);
?>
Switching back, though, is, well...simple.
<?php
//$dom is a DOMDocument instance
$xml = simplexml_import_dom($dom);
?>//No need to initiate, import and append on example#1
(...)
$dom_sxe = dom_import_simplexml($sxe);
if (!$dom_sxe) {
echo 'Erreur lors de la conversion du XML';
exit;
}
//$dom = new DOMDocument('1.0');
//$dom_sxe = $dom->importNode($dom_sxe, true);
//$dom_sxe = $dom->appendChild($dom_sxe);
//use ownerDocument propertie
echo $dom->ownerDocument->saveXML();
?>Very useful to add a CDATA node with SimpleXMLElement (use it like addChild) :
<?php
class My_SimpleXMLElement extends SimpleXMLElement {
public function addChildWithCData($name, $value = NULL) {
$new_child = $this->addChild($name);
$node = dom_import_simplexml($new_child);
$no = $node->ownerDocument;
$node->appendChild($no->createCDATASection($value));
return $new_child;
}
}