/**
   *  Implementation of the crawler page.
   */     
  function security_scanner_cron() {
    global $base_url;
    //  Check if the auth session cookie value is already into the db, otherwise call
    //  the function that retrieve this (enable multithreading)
    if (variable_get('security_scanner_cookie','') == '') {
      drupal_security_scanner_get_auth_cookie();
    }
    $time = time() + 25;
    while (time() < $time) {
      // Initialize the crawler
      db_query('INSERT INTO {crawler} VALUES (default)');
      $crawler_id = db_last_insert_id('crawler', 'id');
      //Mark the extracted page as visited
      db_query("UPDATE {crawler_links} SET crawler_id = %d, status = 1 WHERE crawler_id = 0 LIMIT 1", $crawler_id);
      // Get the link from crawler_links table 
      $page_to_visit = db_fetch_array(db_query("SELECT id,path FROM {crawler_links} WHERE crawler_id = %d AND status = 1 LIMIT 1", $crawler_id));
      // Update the status field to sign as executed that link
      db_query("UPDATE {crawler_links} SET status = 1 WHERE crawler_id = %d and status = 1 LIMIT 1", $crawler_id);
      // Create a new object and parse the page
      // $obj = new drupal_security_scanner_test();
      $obj = new drupal_security_scanner_test();
      // Set the cookie
      $session_cookie = variable_get('security_scanner_cookie','');
      $obj->curl_options = array(
        CURLOPT_COOKIE => $session_cookie,
      );
      $obj->drupalGet($page_to_visit['path']);
      $obj->parse();
      $links = $obj->elements->xpath('//a');      
      foreach($links as $link) {
        $url_to_save = (string)$link->attributes()->href;
        $absolute = getAbsoluteUrl($url_to_save);
        // Get the page but check if it's logout link, that makes me lose the cookie!
        $parsed_url = parse_url($absolute);
        if ($parsed_url['query'] != 'q=logout') {  
          if (substr($absolute, 0, strlen($base_url)) == $base_url) {
            // Here we use IGNORE to insert only one time a link into the table. ("path" is a unique index)
            db_query("INSERT IGNORE INTO {crawler_links} VALUES ('','%s','','')", $absolute);
          }
        }
      }
      // Get the forms inside the page
      $forms = $obj->elements->xpath('//form');
      foreach($forms as $form) {
        // Here we use again IGNORE to insert only one time a form_id into the table. ("form_id" is the primary key)
        $form->getAttribute('id');
        echo "<br />id: ".$page_to_visit['id'].'<br />';
        echo "<br /><br />";
        //db_query("INSERT IGNORE INTO {crawler_forms} VALUES ('%s','%d')", $form->, $page_to_visit['id']);
      }
      db_query("UPDATE {crawler_links} SET status = 2 WHERE crawler_id = %d and status = 1 LIMIT 1", $crawler_id);
    }
    // This has to be removed because the cookie has to stay into the databes to enable multiple istances of the crawler 
    variable_del('security_scanner_cookie');
    $obj->curlClose();
    return '<p>'. t('The quick brown fox jumps over the lazy dog.') .'</p>';
  }
  
  /**
   *  Get the cookie of the admin and insert the first link into the table crawler_links.
   *  There is an issue, I have to start the crawler from uid different than 1.    
   */
   function drupal_security_scanner_get_auth_cookie() {
    $initial_path = user_pass_reset_url(user_load(1));
    // Add sleep to go round a bug inside a drupal core function. Remove it when it's changed into core.
    sleep(1);
    //  Create a new object, set cURL options to call the function drupal_security_scanner_curl_headers that
    //  saves into the variable table the admin cookie. Then set the cookie.
    $obj = new drupal_security_scanner_test();
    $obj->curl_options = array(
      CURLOPT_HEADERFUNCTION => 'drupal_security_scanner_curl_headers',
      CURLOPT_FOLLOWLOCATION => 0,
    );
    // Get the page with password reset and push submit button
    $obj->drupalGet($initial_path);
    $obj->drupalPost($initial_path,'',TRUE);
    //  Add the first url into the crawler_links table.
    db_query("INSERT INTO {crawler_links} VALUES ('','%s','','')", url('admin', array('absolute' => TRUE)));
    return true;
  }
  
  /**
   *  This function will extract headers and return the lenght.
   */  
 function drupal_security_scanner_curl_headers($ch = NULL, $header = NULL) { 
    static $headers = array();
    if (!isset($ch)) {
      return $headers;
    }
    if(!strncmp($header, "Set-Cookie:", 11)) { 
      //  get the cookie
      $cookiestr = trim(substr($header, 11, -1));
      $cookie = explode(';', $cookiestr);
      variable_set('security_scanner_cookie', $cookie[0]);
    }
    return strlen($header);   
  }