dio_smart_retry 1.4.0

Retry library for Dio package made with love. By default, the request will be retried only for appropriate retryable http statuses.

Dio Smart Retry

Flexible retry library for Dio package. This is a next generation of an abandoned dio_retry package.
By default, the request will be retried only for appropriate retryable http statuses.
Also, it supports dynamic delay between retries.
Null Safety.

Contents

• Getting Started
• Usage
• Default retryable status codes list
• Disable retry
• Add extra retryable status codes
• Override retryable statuses
• Retry requests with multipart/form-data

Getting Started

1. Add package to pubspec.yaml: dio_smart_retry: ^1.4.0
2. Import package: import 'package:dio_smart_retry/dio_smart_retry.dart'

Usage

Just add an interceptor to your dio:

final dio = Dio();
// Add the interceptor
dio.interceptors.add(RetryInterceptor(
  dio: dio,
  logPrint: print, // specify log function (optional)
  retries: 3, // retry count (optional)
  retryDelays: const [ // set delays between retries (optional)
    Duration(seconds: 1), // wait 1 sec before first retry
    Duration(seconds: 2), // wait 2 sec before second retry
    Duration(seconds: 3), // wait 3 sec before third retry
  ],
));

/// Sending a failing request for 3 times with 1s, then 2s, then 3s interval
await dio.get('https://mock.codes/500');

See example/dio_smart_retry_example.dart.

Default retryable status codes list

Responses with these http status codes will be retried by default:

• 408: RequestTimeout
• 429: TooManyRequests
• 500: InternalServerError
• 502: BadGateway
• 503: ServiceUnavailable
• 504: GatewayTimeout
• 440: LoginTimeout (IIS)
• 460: ClientClosedRequest (AWS Elastic Load Balancer)
• 499: ClientClosedRequest (ngnix)
• 520: WebServerReturnedUnknownError
• 521: WebServerIsDown
• 522: ConnectionTimedOut
• 523: OriginIsUnreachable
• 524: TimeoutOccurred
• 525: SSLHandshakeFailed
• 527: RailgunError
• 598: NetworkReadTimeoutError
• 599: NetworkConnectTimeoutError It's possible to override this list

Disable retry

It's possible to manually disable retry for a specified request. Use disableRetry extension for that:

final request = RequestOptions(path: '/')
  ..disableRetry = true;
await dio.fetch<String>(request);

or

final options = Options()
  ..disableRetry = true;
await dio.get<String>('/', options: options);

Add extra retryable status codes

It's possible to add you own retryable status codes. Use retryableExtraStatuses parameter for that. Here is an example:

RetryInterceptor(
  dio: dio,
  retryableExtraStatuses: { status401Unauthorized },
)

or:

RetryInterceptor(
  dio: dio,
  retryableExtraStatuses: { 401 },
)

Override retryable statuses

It's possible to override default retryable status codes list. Just make new instance of DefaultRetryEvaluator and pass your status codes there.
Here is an example:

final myStatuses = { status400BadRequest, status409Conflict };
dio.interceptors.add(
  RetryInterceptor(
    dio: dio,
    logPrint: print,
    retryEvaluator: DefaultRetryEvaluator(myStatuses).evaluate,
  ),
);

await dio.get<dynamic>('https://mock.codes/400');

Retry requests with multipart/form-data

Because dio's class for multipart data MultipartFile doesn't support stream rewinding (recreation) to support retry for multipart data you should use a class MultipartFileRecreatable instead of MultipartFile.
Here is an example:

final formData =
    FormData.fromMap({'file': MultipartFileRecreatable.fromFileSync('README.md')});
  await dio.post<dynamic>(
    'https://multipart.free.beeceptor.com/post500',
    data: formData,
  );

See the full example in the test: https://github.com/rodion-m/dio_smart_retry/blob/63a3bddae8b5a0581c35c4ae5e973996561d9100/test/multipart_retry_tests.dart#L32-L61