SubmissionSearchIndex.inc.php

<?php
 
import('lib.pkp.classes.search.SearchFileParser');
import('lib.pkp.classes.search.SearchHTMLParser');
import('lib.pkp.classes.search.SearchHelperParser');
 
define('SEARCH_STOPWORDS_FILE', 'lib/pkp/registry/stopwords.txt');
 
// Words are truncated to at most this length
define('SEARCH_KEYWORD_MAX_LENGTH', 40);
 
abstract class SubmissionSearchIndex {
   public function filterKeywords($text, $allowWildcards = false) {
      $minLength = Config::getVar('search', 'min_word_length');
      $stopwords = $this->_loadStopwords();
 
      // Join multiple lines into a single string
      if (is_array($text)) $text = join("\n", $text);
 
      // Remove punctuation
      $text = PKPString::regexp_replace('/[!"\#\$%\'\(\)\.\?@\[\]\^`\{\}~]/', '', $text);
      $text = PKPString::regexp_replace('/[\+,:;&\/<=>\|\\\]/', ' ', $text);
      $text = PKPString::regexp_replace('/[\*]/', $allowWildcards ? '%' : ' ', $text);
      $text = PKPString::strtolower($text);
 
      // Split into words
      $words = PKPString::regexp_split('/\s+/', $text);
 
      // FIXME Do not perform further filtering for some fields, e.g., author names?
 
      // Remove stopwords
      $keywords = array();
      foreach ($words as $k) {
         if (!isset($stopwords[$k]) && PKPString::strlen($k) >= $minLength && !is_numeric($k)) {
            $keywords[] = PKPString::substr($k, 0, SEARCH_KEYWORD_MAX_LENGTH);
         }
      }
      return $keywords;
   }
 
   protected function _loadStopwords() {
      static $searchStopwords;
 
      if (!isset($searchStopwords)) {
         // Load stopwords only once per request
         $searchStopwords = array_count_values(
            array_filter(
               array_map('trim', file(SEARCH_STOPWORDS_FILE)),
               function($a) {
                  return !empty($a) && $a[0] != '#';
               }
            )
         );
         $searchStopwords[''] = 1;
      }
 
      return $searchStopwords;
   }
 
   abstract function submissionChangesFinished();
 
   abstract public function submissionMetadataChanged($submission);
 
   abstract function clearSubmissionFiles($submission);
}