WP_REST_Templates_Controller::_sanitize_template_id() WordPress Method

	public function _sanitize_template_id( $id ) {
		$id = urldecode( $id );

		$last_slash_pos = strrpos( $id, '/' );
		if ( false === $last_slash_pos ) {
			return $id;
		}

		$is_double_slashed = substr( $id, $last_slash_pos - 1, 1 ) === '/';
		if ( $is_double_slashed ) {
			return $id;
		}
		return (
			substr( $id, 0, $last_slash_pos )
			. '/'
			. substr( $id, $last_slash_pos )
		);
	}