Developer should throw custom exception in interceptor

[WutangNailao]

Request Statement

When i write a interceptor class extends Interceptor, in some case, i wish throw some exception to tell the developer some thing went wrong. so i throw a custom exception in override function 'onResponse', but this exception was catched by DioException, and this exception can not tell me more infomation about this error.

So, i wish this will be supported

Solution Brainstorm

No response

[ueman]

This makes a lot of sense.

I think we either should properly wrap the exception, or we shouldn't wrap it at all.

[kuhnroyal]

I think we do.

Just from looking at the screens, the reported exception probably originated at the jsonDecode.

[AlexV525]

These (#1949) are quite similar which requires a nicer first-look regarding the exception.

[kuhnroyal]

Adding request information to the exception is one thing. Figuring out a sensible way to convert arbitrary exceptions/objects into strings is another. Any ideas for this? We call toString() on the inner error but we don't always pass a message to the DioException - that is why it says [unknown]: null.

[SpeedReach]

DioException has a error field, this is probably what you're looking for?

dio/dio/lib/src/dio_exception.dart

Lines 176 to 178 in 4d7ea68

	/// The original error/exception object;
	/// It's usually not null when `type` is [DioExceptionType.unknown].
	final Object? error;

[AlexV525]

Based on the above comments, the root cause of the exception is the JSON fails to be decoded before it reaches your exception, so a FormatException was thrown. Otherwise, it would be DioException(APIException).

Closing as it's working as intended.

[WutangNailao]

it's my wrong, i show a wrong example.
this is a good example i think for my issue.

when i get a response with code 401, i throw a apiexception, in the terminal, i see which i throwed apiexception, but it wrapped with dioException, so i can't not catch this error exactly next time.

[kuhnroyal]

Not sure how we can achieve that other than the developer registering custom types somewhere.