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Description:

dio smart retry

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 #

Dio Smart Retry

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

Getting Started for Dio #

Add package to pubspec.yaml: dio_smart_retry: ^5.0.0 **
Import package: import 'package:dio_smart_retry/dio_smart_retry.dart'

** For the old dio (ver. 4.+) use dio_smart_retry: ^1.4.0
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');
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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);
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or
final options = Options()
..disableRetry = true;
await dio.get<String>('/', options: options);
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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 },
)
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or:
RetryInterceptor(
dio: dio,
retryableExtraStatuses: { 401 },
)
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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');
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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,
);
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See the full example in the test: https://github.com/rodion-m/dio_smart_retry/blob/63a3bddae8b5a0581c35c4ae5e973996561d9100/test/multipart_retry_tests.dart#L32-L61
Migrating to 6.0 #
Version 6.0 introduces 2 breaking changes:

MultipartFileRecreatable.filename is now a named parameter
MultipartFileRecreatable.filePath is now removed

To update to the latest version, if you were using the MultipartFileRecreatable constructor, remove the filePath parameter and change filename to a named parameter:
Old:
return MultipartFileRecreatable(
stream,
length,
filename,
filePath,
);
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New:
return MultipartFileRecreatable(
stream,
length,
filename: filename,
);
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