Create a file with following code - define('WS_SERVER', true); require_once(__DIR__ . '/config.php'); require_once("lib/externallib.php"); require_once($CFG->libdir . "/filelib.php"); $settings = external_settings::get_instance(); print_object(external_settings::get_instance()->get_file()); print_object( file_rewrite_pluginfile_urls( '@@PLUGINFILE@@/1.jpg', external_settings::get_instance()->get_file(), 2, "t", "X", 3)); Load the page and make sure the output is as below - webservice/pluginfile.php http://localhost/stable_master/webservice/pluginfile.php/2/t/X/3/1.jpg Now remove the first line of WS_SERVER declaration from the code and load it again. Make sure the output is - pluginfile.php http://localhost/stable_master/pluginfile.php/2/t/X/3/1.jpg