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<?php
/**
* ownCloud - News
*
* This file is licensed under the Affero General Public License version 3 or
* later. See the COPYING file.
*
* @author Alessandro Cosentino <cosenal@gmail.com>
* @author Bernhard Posselt <dev@bernhard-posselt.com>
* @copyright Alessandro Cosentino 2012
* @copyright Bernhard Posselt 2012, 2014
*/
namespace OCA\News\ArticleEnhancer;
use \DOMDocument;
use \DOMXpath;
use \ZendXml\Security;
use \PicoFeed\Encoding\Encoding;
use \OCA\News\Utility\PicoFeedClientFactory;
use \OCA\News\Db\Item;
class XPathArticleEnhancer implements ArticleEnhancer {
private $maximumTimeout;
private $clientFactory;
private $regexXPathPair;
/**
* @param \Utility\PicoFeedClientFactory $clientFactory
* @param array $regexXPathPair an associative array containing regex to
* match the url and the xpath that should be used for it to extract the
* page
*/
public function __construct(PicoFeedClientFactory $clientFactory,
array $regexXPathPair){
$this->clientFactory = $clientFactory;
$this->regexXPathPair = $regexXPathPair;
}
/**
* @param \OCA\News\Db\Item $item
* @return \OCA\News\Db\Item enhanced item
*/
public function enhance(Item $item){
foreach($this->regexXPathPair as $regex => $search) {
if(preg_match($regex, $item->getUrl())) {
$body = $this->getFile($item->getUrl());
$body = mb_convert_encoding($body, 'HTML-ENTITIES',
mb_detect_encoding($body));
$dom = new DOMDocument();
Security::scan($body, $dom, function ($xml, $dom) {
return @$dom->loadHTML($xml, LIBXML_NONET);
});
$xpath = new DOMXpath($dom);
$xpathResult = $xpath->evaluate($search);
// in case it wasnt a text query assume its a dom element and
// convert it to text
if(!is_string($xpathResult)) {
$xpathResult = $this->domToString($xpathResult);
}
$xpathResult = trim($xpathResult);
// convert all relative to absolute URLs
$xpathResult = $this->substituteRelativeLinks(
$xpathResult, $item->getUrl()
);
if($xpathResult) {
$item->setBody($xpathResult);
}
}
}
return $item;
}
private function getFile($url) {
$client = $this->clientFactory->build();
$client->execute($url);
$client->setUserAgent('Mozilla/5.0 AppleWebKit');
return $client->getContent();
}
/**
* Method which converts all relative "href" and "src" URLs of
* a HTML snippet with their absolute equivalent
* @param string $xmlString a HTML snippet as string with the relative URLs
* to be replaced
* @param string $absoluteUrl the approptiate absolute url of the HTML
* snippet
* @return string the result HTML snippet as a string
*/
protected function substituteRelativeLinks($xmlString, $absoluteUrl) {
$dom = new DOMDocument();
$dom->preserveWhiteSpace = false;
$isOk = Security::scan($xmlString, $dom, function ($xml, $dom) {
// wrap in div to prevent loadHTML from inserting weird elements
$xml = '<div>' . $xml . '</div>';
return @$dom->loadHTML($xml, LIBXML_NONET | LIBXML_HTML_NODEFDTD
| LIBXML_HTML_NOIMPLIED);
});
if($xmlString === '' || !$isOk) {
return false;
}
foreach (['href', 'src'] as $attribute) {
$xpath = new DOMXpath($dom);
$xpathResult = $xpath->query(
"//*[@" . $attribute . " " .
"and not(contains(@" . $attribute . ", '://')) " .
"and not(starts-with(@" . $attribute . ", 'mailto:')) " .
"and not(starts-with(@" . $attribute . ", '//'))]");
foreach ($xpathResult as $linkNode) {
$urlElement = $linkNode->attributes->getNamedItem($attribute);
$abs = $this->relativeToAbsoluteUrl(
$urlElement->nodeValue, $absoluteUrl
);
$urlElement->nodeValue = htmlspecialchars($abs);
}
}
$xmlString = $dom->saveHTML();
// domdocument spoils the string with line breaks between the elements
// strip them
$xmlString = str_replace("\n", '', $xmlString);
return $xmlString;
}
/**
* Method which builds a URL by taking a relative URL and its corresponding
* absolute URL
* @param string $relativeUrl the relative URL
* @param string $absoluteUrl the absolute URL with at least scheme and host
* @return string the resulting absolute URL
*/
protected function relativeToAbsoluteUrl($relativeUrl, $absoluteUrl) {
$base = new \Net_URL2($absoluteUrl);
return $base->resolve($relativeUrl);
}
/**
* Method which turns an xpath result to a string
* you can customize it by overwriting this method
* @param mixed $xpathResult the result from the xpath query
* @return string the result as a string
*/
protected function domToString($xpathResult) {
$result = '';
foreach($xpathResult as $node) {
$result .= $this->toInnerHTML($node);
}
return $result;
}
protected function toInnerHTML($node) {
$dom = new DOMDocument();
$dom->appendChild($dom->importNode($node, true));
return trim($dom->saveHTML($dom->documentElement));
}
}
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