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<?php
/**
* ownCloud - News
*
* @author Alessandro Cosentino
* @author Bernhard Posselt
* @copyright 2012 Alessandro Cosentino cosenal@gmail.com
* @copyright 2012 Bernhard Posselt dev@bernhard-posselt.com
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
* License as published by the Free Software Foundation; either
* version 3 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*/
namespace OCA\News\ArticleEnhancer;
use \OCA\News\Utility\SimplePieFileFactory;
use \OCA\News\Db\Item;
class XPathArticleEnhancer implements ArticleEnhancer {
private $feedRegex;
private $purifier;
private $fileFactory;
private $maximumTimeout;
/**
* @param $purifier the purifier object to clean the html which will be
* matched
* @param SimplePieFileFactory a factory for getting a simple pie file instance
* @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
* @param int $maximumTimeout maximum timeout in seconds, defaults to 10 sec
*/
public function __construct($purifier, SimplePieFileFactory $fileFactory,
array $regexXPathPair, $maximumTimeout=10){
$this->purifier = $purifier;
$this->regexXPathPair = $regexXPathPair;
$this->fileFactory = $fileFactory;
$this->maximumTimeout = $maximumTimeout;
}
public function enhance(Item $item){
foreach($this->regexXPathPair as $regex => $search) {
if(preg_match($regex, $item->getUrl())) {
$file = $this->fileFactory->getFile($item->getUrl(), $this->maximumTimeout, "Mozilla/5.0 AppleWebKit");
// convert encoding by detecting charset from header
$contentType = $file->headers['content-type'];
if( preg_match( '/(?<=charset=)[^;]*/', $contentType, $matches ) ) {
$body = mb_convert_encoding($file->body, 'HTML-ENTITIES', $matches[0]);
} else {
$body = $file->body;
}
$dom = new \DOMDocument();
@$dom->loadHTML($body);
$xpath = new \DOMXpath($dom);
$xpathResult = $xpath->evaluate($search);
// in case it wasnt a text query assume its a single
if(!is_string($xpathResult)) {
$xpathResult = $this->domToString($xpathResult);
}
// convert all relative to absolute URLs
$xpathResult = $this->substituteRelativeLinks($xpathResult, $item->getUrl());
$sanitizedResult = $this->purifier->purify($xpathResult);
if( $sanitizedResult ) {
$item->setBody($sanitizedResult);
}
}
}
return $item;
}
/**
* 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();
$dom->preserveWhiteSpace = false;
// return, if xml is empty or loading the HTML fails
if( trim($xmlString) == "" || !@$dom->loadHTML($xmlString) ) {
return $xmlString;
}
// remove <!DOCTYPE
$dom->removeChild($dom->firstChild);
// remove <html></html>
$dom->replaceChild($dom->firstChild->firstChild, $dom->firstChild);
$substitution = array("href", "src");
foreach ($substitution as $attribute) {
$xpath = new \DOMXpath($dom);
$xpathResult = $xpath->query(
"//*[@" . $attribute . " " .
"and not(contains(@" . $attribute . ", '://')) " .
"and not(starts-with(@" . $attribute . ", 'mailto:'))]");
foreach ($xpathResult as $linkNode) {
$urlElement = $linkNode->attributes->getNamedItem($attribute);
$abs = $this->relativeToAbsoluteUrl( $urlElement->nodeValue, $absoluteUrl );
$urlElement->nodeValue = htmlspecialchars($abs);
}
}
// save dom to string and remove <body></body>
$xmlString = substr(trim($dom->saveHTML()), 6, -7);
// 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
* For examle relative URL "../example/path/file.php?a=1#anchor" and
* absolute URL "https://username:password@www.website.com/subfolder/index.html"
* will result in "https://username:password@www.website.com/example/path/file.php?a=1#anchor"
* @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) {
$abs = parse_url($absoluteUrl);
$newUrl = $abs["scheme"]."://"
.( (isset($abs["user"])) ? $abs["user"] . ( (isset($abs["pass"])) ? ":".$abs["pass"] : "") . "@" : "" )
.$abs["host"]
.( (isset($abs["port"])) ? ":".$abs["port"] : "" );
if(substr(trim($relativeUrl), 0, 1) == "/") {
// we have a relative url like "/a/path/file"
return $newUrl . $relativeUrl;
} else {
// we have a relative url like "a/path/file", handle "."" and ".." directories
// the starting point is the absolute path, but with out the last part (we don't need the file name)
$newPath = explode("/", substr($abs["path"], 1) );
array_pop($newPath);
$relPath = parse_url($relativeUrl, PHP_URL_PATH);
$relPath = explode("/", $relPath);
// cross the relative and the absolute path
for($i=0; $i<count($relPath)-1; $i++) {
if($relPath[$i] == ".") {
continue;
} elseif($relPath[$i] == "..") {
array_pop($newPath);
} else {
$newPath[] = $relPath[$i];
}
}
// add the last part (the file name) of the relative URL
$newPath[] = $relPath[ count($relPath)-1 ];
$newPath = implode("/", $newPath);
$rel = parse_url($relativeUrl);
return $newUrl . "/" . $newPath
. ( (isset($rel["query"])) ? "?".$rel["query"] : "")
. ( (isset($rel["fragment"])) ? "#".$rel["fragment"] : "");
}
}
/**
* Method which turns an xpath result to a string
* you can customize it by overwriting this method
* @param $xpathResult the result from the xpath query
* @return the result as a string
*/
protected function domToString($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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