public static function upload_parameters() {
        return new external_function_parameters(
            array(
                'contextid' => new external_value(PARAM_INT, 'context id', VALUE_DEFAULT, null),
                'component' => new external_value(PARAM_COMPONENT, 'component'),
                'filearea'  => new external_value(PARAM_AREA, 'file area'),
                'itemid'    => new external_value(PARAM_INT, 'associated id'),
                'filepath'  => new external_value(PARAM_PATH, 'file path'),
                'filename'  => new external_value(PARAM_FILE, 'file name'),
                'filecontent' => new external_value(PARAM_TEXT, 'file content'),
                'contextlevel' => new external_value(PARAM_ALPHA, 'The context level to put the file in,
                        (block, course, coursecat, system, user, module)', VALUE_DEFAULT, null),
                'instanceid' => new external_value(PARAM_INT, 'The Instance id of item associated
                         with the context level', VALUE_DEFAULT, null)
            )
        );
    }