i am unable to catch dio error

[mohadel92]

New Issue Checklist

• [true ] I have searched for a similar issue in the project and found none

Issue Info

Info	Value
Platform Name	e.g. flutter / ios / android
Platform Version	e.g. 2.2.0 / 12.0 / 9.0
Dio Version	e.g. 4..0.0
Android Studio / Xcode Version	e.g. Android Studio 4.1 / Xcode 12.4

Issue Description and Steps

i used to use dio since older version
i catch errors with

 e.response.data
e.response.headers

now after migrating to null safety
and flutter 2.2 i cannot catch any errors i get message

any help?

[bagus-repository]

please make sure you are catching a DioError Object see Handling Error.

[dhsont]

DioError is not capturing any 400-> 500 errors

[mohadel92]

@bagus-repository thanks but i have never used this method
and all apps used to work fine

[rymesaint]

DioError is not capturing any errors, because when i'm adding headers to the options

[ApoorvaAditya]

I had a similar problem when I migrated my app to null safety and dio from 3.0.10 to 4.0.0. After bunch of testing I found out that an onError interceptor was the cause of the problem for me. The interceptor basically consumed the error and didn't pass the error back to the calling function and therefore no exception/error was being caught.

I fixed it by using the ErrorInterceptorHandler parameter of the onError function of the interceptor and adding a ErrorInterceptorHandler.reject(error); at the end of the onError function. Here's an example:

dio.interceptors.add(
  InterceptorsWrapper(
    onError: (error, handler) {
      // Do stuff here
      handler.reject(error); // Added this line to let error propagate outside the interceptor
    },
  ),
);

[sopherwang]

I had a similar problem when I migrated my app to null safety and dio from 3.0.10 to 4.0.0. After bunch of testing I found out that an onError interceptor was the cause of the problem for me. The interceptor basically consumed the error and didn't pass the error back to the calling function and therefore no exception/error was being caught.

I fixed it by using the ErrorInterceptorHandler parameter of the onError function of the interceptor and adding a ErrorInterceptorHandler.reject(error); at the end of the onError function. Here's an example:

dio.interceptors.add(
  InterceptorsWrapper(
    onError: (error, handler) {
      // Do stuff here
      handler.reject(error); // Added this line to let error propagate outside the interceptor
    },
  ),
);

Hi @ApoorvaAditya Thanks for the solution. But I's still not able to catch the exceptions. I can see the exceptions go through the intercepted callbacks but after reject the error, it exception still unhandled. Would you mind providing more detailed solution? Thanks.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If this is still an issue, please make sure it is up to date and if so, add a comment that this is still an issue to keep it open. Thank you for your contributions.

[shakthizen]

I found a hacky solution. We are overriding all the exceptions thrown by default. Then we are going to create custom interceptor to handle and throw exceptions. This way we can catch the DioException as we did before.

1. Create a base client like this. You have to set validateStatus function to return true whatever the status code is.

final baseOptions = BaseOptions(
  baseUrl: host,
  contentType: Headers.jsonContentType,
  validateStatus: (int? status) {
    return status != null;
    // return status != null && status >= 200 && status < 300;
  },
);

final dio = Dio(baseOptions);

2. Create a custom interceptor to raise exceptions

class ErrorInterceptor extends Interceptor {
  @override
  void onResponse(Response response, ResponseInterceptorHandler handler) {
    final status = response.statusCode;
    final isValid = status != null && status >= 200 && status < 300;
    if (!isValid) {
      throw DioException.badResponse(
        statusCode: status!,
        requestOptions: response.requestOptions,
        response: response,
      );
    }
    super.onResponse(response, handler);
  }
}

3. Add that to the Dio interceptors list

dio.interceptors.addAll([
    ErrorInterceptor(),
]);

Link to my gist https://gist.github.com/shakthizen/d644aaf19ca837a4a29a92ebad551055