protected function view_plugin_page() {
        global $USER;

        $o = '';

        $pluginsubtype = required_param('pluginsubtype', PARAM_ALPHA);
        $plugintype = required_param('plugin', PARAM_PLUGIN);
        $pluginaction = required_param('pluginaction', PARAM_ALPHA);

        $plugin = $this->get_plugin_by_type($pluginsubtype, $plugintype);
        if (!$plugin) {
            print_error('invalidformdata', '');
            return;
        }

        $o .= $plugin->view_page($pluginaction);

        return $o;
    }