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<?php
/**
* @package s9e\TextFormatter
* @copyright Copyright (c) 2010-2022 The s9e authors
* @license http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\TextFormatter\Configurator\Helpers;
use DOMDocument;
use DOMElement;
use DOMXPath;
use RuntimeException;
abstract class TemplateLoader
{
/**
* XSL namespace
*/
const XMLNS_XSL = 'http://www.w3.org/1999/XSL/Transform';
/**
* Get the XML content of an element
*
* @private
*
* @param DOMElement $element
* @return string
*/
public static function innerXML(DOMElement $element)
{
// Serialize the XML then remove the outer element
$xml = $element->ownerDocument->saveXML($element);
$pos = 1 + strpos($xml, '>');
$len = strrpos($xml, '<') - $pos;
// If the template is empty, return an empty string
return ($len < 1) ? '' : substr($xml, $pos, $len);
}
/**
* Load a template as an xsl:template node
*
* Will attempt to load it as XML first, then as HTML as a fallback. Either way, an xsl:template
* node is returned
*
* @param string $template
* @return DOMDocument
*/
public static function load($template)
{
$dom = self::loadAsXML($template) ?: self::loadAsXML(self::fixEntities($template));
if ($dom)
{
return $dom;
}
// If the template contains an XSL element, abort now. Otherwise, try reparsing it as HTML
if (strpos($template, '<xsl:') !== false)
{
$error = libxml_get_last_error();
throw new RuntimeException('Invalid XSL: ' . $error->message);
}
return self::loadAsHTML($template);
}
/**
* Serialize a loaded template back into a string
*
* NOTE: removes the root node created by load()
*
* @param DOMDocument $dom
* @return string
*/
public static function save(DOMDocument $dom)
{
$xml = self::innerXML($dom->documentElement);
if (strpos($xml, 'xmlns:xsl') !== false)
{
$xml = preg_replace('((<[^>]+?) xmlns:xsl="' . self::XMLNS_XSL . '")', '$1', $xml);
}
return $xml;
}
/**
* Replace HTML entities and unescaped ampersands in given template
*
* @param string $template
* @return string
*/
protected static function fixEntities($template)
{
$template = self::replaceEntities($template);
$template = preg_replace('(&(?!quot;|amp;|apos;|lt;|gt;|#\\d+;|#x[A-Fa-f0-9]+;))', '&', $template);
return $template;
}
/**
* Load given HTML template in a DOM document
*
* @param string $template Original template
* @return DOMDocument
*/
protected static function loadAsHTML($template)
{
$template = self::replaceCDATA($template);
$template = self::replaceEntities($template);
$dom = new DOMDocument;
$html = '<?xml version="1.0" encoding="utf-8" ?><html><body><div>' . $template . '</div></body></html>';
$useErrors = libxml_use_internal_errors(true);
$dom->loadHTML($html, LIBXML_NSCLEAN);
self::removeInvalidAttributes($dom);
libxml_use_internal_errors($useErrors);
// Now dump the thing as XML then reload it with the proper root element
$xml = '<?xml version="1.0" encoding="utf-8" ?><xsl:template xmlns:xsl="' . self::XMLNS_XSL . '">' . self::innerXML($dom->documentElement->firstChild->firstChild) . '</xsl:template>';
$useErrors = libxml_use_internal_errors(true);
$dom->loadXML($xml, LIBXML_NSCLEAN);
libxml_use_internal_errors($useErrors);
return $dom;
}
/**
* Load given XSL template in a DOM document
*
* @param string $template Original template
* @return bool|DOMDocument DOMDocument on success, FALSE otherwise
*/
protected static function loadAsXML($template)
{
$xml = '<?xml version="1.0" encoding="utf-8" ?><xsl:template xmlns:xsl="' . self::XMLNS_XSL . '">' . $template . '</xsl:template>';
$useErrors = libxml_use_internal_errors(true);
$dom = new DOMDocument;
$success = $dom->loadXML($xml, LIBXML_NOCDATA | LIBXML_NSCLEAN);
self::removeInvalidAttributes($dom);
libxml_use_internal_errors($useErrors);
return ($success) ? $dom : false;
}
/**
* Remove attributes with an invalid name from given DOM document
*
* @param DOMDocument $dom
* @return void
*/
protected static function removeInvalidAttributes(DOMDocument $dom)
{
$xpath = new DOMXPath($dom);
foreach ($xpath->query('//@*') as $attribute)
{
if (!preg_match('(^(?:[-\\w]+:)?(?!\\d)[-\\w]+$)D', $attribute->nodeName))
{
$attribute->parentNode->removeAttributeNode($attribute);
}
}
}
/**
* Replace CDATA sections in given template
*
* @param string $template Original template
* @return string Modified template
*/
protected static function replaceCDATA($template)
{
return preg_replace_callback(
'(<!\\[CDATA\\[(.*?)\\]\\]>)',
function ($m)
{
return htmlspecialchars($m[1]);
},
$template
);
}
/**
* Replace known HTML entities
*
* @param string $template
* @return string
*/
protected static function replaceEntities(string $template): string
{
return preg_replace_callback(
'(&(?!quot;|amp;|apos;|lt;|gt;)\\w+;)',
function ($m)
{
return html_entity_decode($m[0], ENT_HTML5 | ENT_NOQUOTES, 'UTF-8');
},
str_replace('&', '&', $template)
);
}
}