public static function get_static_base_url()
 {
     if (!self::$static_base_url) {
         global $_FILE_TO_URL_MAPPING;
         if (!empty($_FILE_TO_URL_MAPPING) && !empty($_FILE_TO_URL_MAPPING[BASE_PATH])) {
             $baseurl = $_FILE_TO_URL_MAPPING[BASE_PATH];
             if (strpos($baseurl, -1) !== "/") {
                 $baseurl .= "/";
             }
             self::$static_base_url = $baseurl;
         }
     }
     return self::$static_base_url;
 }