Hello, `ResponseException` is not serializable, it...

# ktor

[Thomas]

Hello, ResponseException is not serializable, it throws a NotSerializableException. This is because of the response field. Can this be changed so it is serializable? https://github.com/ktorio/ktor/blob/178479ba392524d37193fcf2f6b30f570a0a3ba7/ktor-client/ktor-client-core/common/src/io/ktor/client/features/DefaultResponseValidation.kt#L51

[e5l]

Hi @Thomas, why do you want serialize the response?

[Thomas]

Hey @e5l, what I am doing is showing the user an appropriate error message depending on the type of exception. To do this, I serialize the exception so I can pass it to a different Android Fragment using a Bundle. That Android Fragment “converts” the exception to a localised error message.

[Thomas]

Maybe I should change it so I first “convert” the exception to a localized message, and put that message in the Bundle instead. However, that would mean I would need to add that to every place in my app where I use Ktor / other possible exceptions. It was way easier to pass the exception to a single place and convert it there.

[Thomas]

Do you understand my use case and have suggestions?

[e5l]

Ok, I've got it. It looks like we can't mark HttpResponse with serializable. Maybe you could write a custom response validator with your own exception(and disable the default)?

[Thomas]

That could be a solution which is very interesting, thanks.

If you look at the source code of Throwable, you can see that it implements Serializable. That is why I assumed that ResponseException would also be serializable. Another popular networking library for Android called Retrofit has something similar. They made the response field transient/nullable. (https://github.com/square/retrofit/blob/master/retrofit/src/main/java/retrofit2/HttpException.java#L30). (also see line 50). Not sure if that is the best way but maybe it gives you some ideas.

[e5l]

Actually transient is a good idea 🙂 Thanks

[Thomas]

I am not really sure how transient works in the background, but could that have any effect on closing the response? So that the response does not leak.

[e5l]

The response in the exception isn't holding any open resources

[Thomas]

@e5l Do you want me to create a GitHub issue for this?

[e5l]

Yep. It’s much easier to track progress together :)

[Thomas]

@e5l https://github.com/ktorio/ktor/issues/1256