Remove some useless methods of 'http_handler'. 'error' method sends error to engine, not http error. Also user can throw exception from handler if something fatal is occured (and worker send error to engine himself), so i think that 'error' method is confusing in http application. Also it seems that users will fill http_response themselves (this includes setting of http code), so 'ok', 'bad_request', etc methods looks useless.