Retrofit, callback for 204 No Content response?

Question

On Android, I initially implemented a Retrofit interface like this:

@DELETE(USER_API_BASE_URL + "/{id}")
public void deleteUser(@Path("id") String id, Callback<User> callback);

The server returns 204 NO CONTENT upon a successful deletion. This was causing the callback to trigger failure, with retrofit.RetrofitError: End of input at character 0 of, as it was expecting a User object back with the response.

I then rewrote it like this, using Void instead of User:

@DELETE(USER_API_BASE_URL + "/{id}")
public void deleteUser(@Path("id") String id, Callback<Void> callback);  <-- VOID

But I am getting the same error from the callback. What is the proper way to fix this? Thank you.

How Retrofit can make `User` when ther's no content in response? Why you want `User` object back, when it was already deleted? — klimat, Jan 14 '15 at 10:17
Does it work with Callback? Also what version of retrofit do you use? — Volodymyr Baydalka, Jan 14 '15 at 10:29
hey Volodymyr, it does work. It doesn't feel like the proper way tho -- the signature of the callback's success method is then `public void success(Response response1, Response response) {..}` which looks a bit weird. — ticofab, Jan 14 '15 at 10:40
@ticofab How did you solved this problem. I am receiving this issue nterface method 'java.io.InputStream retrofit.mime.TypedInput.in()' on a null object reference. Could you please help me with this — Akshay Mukadam, Feb 10 '16 at 10:41
@AkshayMukadam I solved it the way is indicated in 2 comments above and one answer below :) use `ResponseCallback`. — ticofab, Feb 10 '16 at 10:56
@ticofab I am trying Uber API I am receiving the above error — Akshay Mukadam, Feb 10 '16 at 11:07

score 31 · Accepted Answer · answered Dec 04 '15 at 21:22

31

Retrofit 2.x no longer has a ResponseCallback as mentioned in the other answer. You want to use a Response<Void> type.

The RxJava declaration:

@PUT Observable<Response<Void>> foo();

The standard declaration:

@PUT Call<Response<Void>> bar();

answered Dec 04 '15 at 21:22

Will Vanderhoef

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But the problem is even if the web service call has an error, it executes success block and not the throwable block – MobileMon Jun 29 '17 at 14:14
I am getting " Cannot serialize abstract class okhttp3.ResponseBody" with retrofit and moshi 2.3.0 – Greg Ennis Jul 27 '17 at 18:06
@GregEnnis You're using the wrong type, it's Response from `retrofit2.Response` – Sammy Patenotte Jul 28 '17 at 16:53
@SammyPatenotte actually this answer is obsolete. In retrofit 2.3.0 using just PUT Call bar() works as expected; no need for Response<> return type. – Greg Ennis Jul 31 '17 at 13:53
Mmh that's weird, in my case it doesn't work with only Void, but I'm using it for POST requests, so I'm not sure if that is the reason why – Sammy Patenotte Jul 31 '17 at 20:29
@MobileMon I have the same problem, when there is error from the server, the success block is called but not the throwable, did you find any solution for this? – Kostadin Georgiev May 27 '19 at 08:03
This answer works out for `@DELETE` for server returning 204. Thanks! – Roon13 Jun 09 '21 at 18:22

ticofab · Answer 2 · 2016-05-20T09:03:18.843

9

The solution was pointed out by Jake Wharton in the comments. Use ResponseCallback.

EDIT: this response is no longer valid for Retrofit < 2.

edited May 20 '16 at 09:03

answered Jan 14 '15 at 16:43

ticofab

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Hey guys, the link in this answer was invalid. -_-||| – codezjx May 20 '16 at 07:51

score 1 · Answer 3 · answered Feb 19 '21 at 18:20

1

This is the kotlin way for the implementation to deal with HTTP 204 and no content.

@DELETE(USER_API_BASE_URL + "/{id}")
suspend fun deleteuser(@HeaderMap headers: Map<String, String>, 
                       @Path("id") id: String)
: Response<Void>

answered Feb 19 '21 at 18:20

flame3

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Using `Response` will be successful for 204 code but will be also successful for 400 code, the throwable block won't be called for 4xx code responses – Victor Feb 16 '22 at 10:23

Retrofit, callback for 204 No Content response?

3 Answers3

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