#! /usr/bin/php
  <?php
  // include shared code
  include 'lib/common.php';
  include 'lib/db.php';
  
  // clear index tables
  $query\; =\; sprintf(\text{'}TRUNCATE\; TABLE$\%sSEARCH_INDEX', DB_TBL_PREFIX);
  mysql_query(query, $GLOBALS[\text{'}DB\text{'}]);$query = sprintf('TRUNCATE TABLE \%sSEARCH_TERM', DB_TBL_PREFIX);
  mysql_query($query,$GLOBALS['DB']);
  
  $query\; =\; sprintf(\text{'}TRUNCATE\; TABLE$\%sSEARCH_DOCUMENT', DB_TBL_PREFIX);
  mysql_query(query, $GLOBALS[\text{'}DB\text{'}]);$// retrieve the list of stop words
  query = sprintf('SELECT TERM_VALUE FROM \%sSEARCH_STOP_WORD', DB_TBL_PREFIX);
  $result\; =\; mysql\_query($query, $GLOBALS[\text{'}DB\text{'}]);$stop_words = array();
  while ($row\; =\; mysql\_fetch\_array($result))
  {
      // since this list will be checked for each word, use term as the array
      // key-- isset($stop\_words[$<term>]) is more efficient than using 
      // in_array(<term>, stop_words)
      $stop\_words[$row['TERM_VALUE']] = true;
  }
  mysql_free_result($result);$// open CURL handle for downloading
  ch = curl_init();
  
  // set curl options
  curl_setopt($ch,\; CURLOPT\_FOLLOWLOCATION,\; true);\; curl\_setopt($ch, CURLOPT_HEADER, false);
  curl_setopt($ch,\; CURLOPT\_RETURNTRANSFER,\; true);\; curl\_setopt($ch, CURLOPT_USERAGENT, 'Search Engine Indexer');
  
  // fetch list of documents to index
  $query\; =\; sprintf(\text{'}SELECT\; DOCUMENT\_URL\; FROM$\%sSEARCH_CRAWL', DB_TBL_PREFIX);
  result = mysql_query($query,$GLOBALS['DB']);
  while ($row\; =\; mysql\_fetch\_array($result))
  {
      echo 'Processing: ' . $row[\text{'}DOCUMENT\_URL\text{'}]\; .\; "...\backslash n";$// retrieve the document's content
      curl_setopt(ch, CURLOPT_URL, $row[\text{'}DOCUMENT\_URL\text{'}]);$file = curl_exec($ch);$file = tidy_repair_string($file);$html = simplexml_load_string($file);$// or: html = @simplexml_load_string($file);$
  
      // extact the title
      if (html->head->title)
      {
          $title\; =$html->head->title;
      }
      else
      {
          // use the filename if a title is not found
          $title\; =\; basename($row['DOCUMENT_URL']);
      }
  
      // extract the description
      $description\; =\; \text{'}No\; description\; provided.\text{'};\; foreach($html->head->meta as $meta)\; \{\; if\; (isset($meta['name']) && $meta[\text{'}name\text{'}]\; ==\; \text{'}description\text{'})\; \{$description = $meta[\text{'}content\text{'}];\; break;\; \}\; \}$// add the document to the index
      query = sprintf('INSERT INTO \%sSEARCH_DOCUMENT (DOCUMENT_URL, ' . 
          'DOCUMENT_TITLE, DESCRIPTION) VALUES ("\%s", "\%s", "\%s")',
          DB_TBL_PREFIX,
          mysql_real_escape_string($row[\text{'}DOCUMENT\_URL\text{'}],$GLOBALS['DB']),
          mysql_real_escape_string($title,$GLOBALS['DB']),
          mysql_real_escape_string($description,$GLOBALS['DB']));
          mysql_query($query,$GLOBALS['DB']);
  
      // retrieve the document's id
      $doc\_id\; =\; mysql\_insert\_id($GLOBALS['DB']);
  
      // strip HTML tags out from the content
      $file\; =\; strip\_tags($file);
  
      // break content into individual words
      foreach (str_word_count($file,\; 1)\; as$index => $word)\; \{$// words should be stored as lowercase for comparisons 
          word = strtolower($word);$// skip word if it appears in the stop words list
          if (isset(stop_words[$word]))\; continue;$// determine if the word already exists in the database
          query = sprintf('SELECT TERM_ID FROM \%sSEARCH_TERM WHERE ' .
              'TERM_VALUE = "\%s"', 
              DB_TBL_PREFIX,
              mysql_real_escape_string($word,$GLOBALS['DB']));
          $result2\; =\; mysql\_query($query, $GLOBALS[\text{'}DB\text{'}]);\; if\; (mysql\_num\_rows($result2))
          {
              // word exists so retrieve its id
              list($word\_id)\; =\; mysql\_fetch\_row($result2);
          }
          else
          {
              // add word to the database
              $query\; =\; sprintf(\text{'}INSERT\; INTO$\%sSEARCH_TERM (TERM_VALUE) ' . 
                  'VALUE ("\%s")',
                  DB_TBL_PREFIX,
                  mysql_real_escape_string(word, $GLOBALS[\text{'}DB\text{'}]));\; mysql\_query($query, $GLOBALS[\text{'}DB\text{'}]);$// determine the word's id
              word_id = mysql_insert_id($GLOBALS[\text{'}DB\text{'}]);\; \}\; mysql\_free\_result($result2);
  
           // add the index record
           $query\; =\; sprintf(\text{'}INSERT\; INTO$\%sSEARCH_INDEX (DOCUMENT_ID, ' .
               'TERM_ID, OFFSET) VALUE (\%d, \%d, \%d)',
               DB_TBL_PREFIX,
               doc_id,
               $word\_id,$index);
           mysql_query($query,$GLOBALS['DB']);
      }
  }
  
  mysql_free_result($result);\; curl\_close($ch);
  echo 'Indexing complete.' . "\n";
  ?>