/**
* Executes this filter
*
* @param article $article reference directly to the article object to filter
*/
public static function filter(&$article)
{
// Can't perform this filter unless language is known
if (!isset($article->language)) {
return;
}
// Stop words are language dependant so this filter relies on previously detected language
$stopWordResource = new \WebArticleExtractor\ResourceProvider("stop_words/" . $article->language . ".lst");
$article->keywords = array();
// Append article title, its likely keywords will be in here.
$sentences = KeywordFilter::getSentences(str_replace('\\u00a0', " ", str_replace("\r\n", '.', $article->title . ". " . $article->text)));
$phrases = KeywordFilter::getPhrases($sentences, $stopWordResource);
$wordScores = KeywordFilter::getWordScores($phrases);
$candidatePhrases = KeywordFilter::getPhraseScores($phrases, $wordScores);
// Clean candidates
foreach ($candidatePhrases as $key => $value) {
if ($value > self::WORD_SCORE_THRESHOLD) {
$article->keywords[] = trim($key);
}
}
//TODO: Weight by candidate phrase's word occurences in other top candidate phrases
}
