onError method

@override Future onError(DioException err, ErrorInterceptorHandler handler)

Called when an exception was occurred during the request.

Implementation

@override
Future<dynamic> onError(
  DioException err,
  ErrorInterceptorHandler handler,
) async {
  if (err.requestOptions.disableRetry) {
    return super.onError(err, handler);
  }
  bool isRequestCancelled() =>
      err.requestOptions.cancelToken?.isCancelled ?? false;

  final attempt = err.requestOptions._attempt + 1;
  final shouldRetry = attempt <= retries && await _shouldRetry(err, attempt);

  if (!shouldRetry) {
    return super.onError(err, handler);
  }

  err.requestOptions._attempt = attempt;
  final delay = _getDelay(attempt);
  logPrint?.call(
    '[${err.requestOptions.path}] An error occurred during request, '
    'trying again '
    '(attempt: $attempt/$retries, '
    'wait ${delay.inMilliseconds} ms, '
    'error: ${err.error ?? err})',
  );

  var requestOptions = err.requestOptions;
  if (requestOptions.data is FormData) {
    try {
      requestOptions = _recreateOptions(err.requestOptions);
    } on RetryNotSupportedException catch (e) {
      return super.onError(
        DioException(requestOptions: requestOptions, error: e),
        handler,
      );
    }
  }

  if (delay != Duration.zero) {
    await Future<void>.delayed(delay);
  }
  if (isRequestCancelled()) {
    logPrint?.call('Request was cancelled. Cancel retrying.');
    return super.onError(err, handler);
  }

  try {
    await dio
        .fetch<void>(requestOptions)
        .then((value) => handler.resolve(value));
  } on DioException catch (e) {
    super.onError(e, handler);
  }
}