Retrofit 2.0 - How to get response body for 400 Bad Request error?

Question

So when I make a POST API call to my server, I get a 400 Bad Request error with JSON response.

{
    \"userMessage\": \"Blah\",
    \"internalMessage\": \"Bad Re         


        

Answer 1

This is how you can handle the response message I am handling for error 500 you can add as much you want

                switch (response.code()) {
                    case HttpURLConnection.HTTP_OK:
                        break;
                    case HttpURLConnection.HTTP_UNAUTHORIZED:
                        callback.onUnAuthentic();
                        break;
                    case HttpURLConnection.HTTP_INTERNAL_ERROR:
                        try {
                            String errorResponse = response.errorBody().string();
                            JSONObject object = new JSONObject(errorResponse);
                            String message = "Error";
                            if (object.has("Message"))
                                message = String.valueOf(object.get("Message"));
                            callback.onError(message);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        break;
                    case HttpURLConnection.HTTP_GATEWAY_TIMEOUT:
                    case HttpURLConnection.HTTP_CLIENT_TIMEOUT:
                    default:
                        callback.onNetworkError();
                        break;
                }

Answer 2

Here is the simplest solution,

If you want to handle the response from onFailure method:

@Override
public void onFailure(Call<T> call, Throwable t) {
    HttpException httpException = (HttpException) t;
    String errorBody = httpException.response().errorBody().string();
    // use Gson to parse json to your Error handling model class
    ErrorResponse errorResponse = Gson().fromJson(errorBody, ErrorResponse.class);
}

Or if you are using rxjava Observable with Kotlin, handle it from error body:

{ error ->
    val httpException :HttpException = error as HttpException
    val errorBody: String = httpException.response().errorBody()!!.string()
    // use Gson to parse json to your Error handling model class
    val errorResponse: ErrorResponse = 
       Gson().fromJson(errorBody, ErrorResponse::class.java)
}

Don't forget to properly handle json to class conversion (use try-catch if not sure).

Answer 3

simply use

 if (throwable is HttpException && (throwable!!.code() == 400 || throwable!!.code()==404)){
                               var responseBody = throwable!!.response()?.errorBody()?.string()
                               val jsonObject = JSONObject(responseBody!!.trim())
                               var message = jsonObject.getString("message")
                               tvValMsg.set(message)
                            } 

Answer 4

I got similar issue, but existing code was stick to RxJava 2 chain. Here's my solution:

   public static <T> Observable<T> rxified(final Call<T> request, final Class<T> klazz) {
    return Observable.create(new ObservableOnSubscribe<T>() {

        AtomicBoolean justDisposed = new AtomicBoolean(false);

        @Override
        public void subscribe(final ObservableEmitter<T> emitter) throws Exception {

            emitter.setDisposable(new Disposable() {
                @Override
                public void dispose() {
                    request.cancel();
                    justDisposed.set(true);
                }

                @Override
                public boolean isDisposed() {
                    return justDisposed.get();
                }
            });

            if (!emitter.isDisposed())
                request.enqueue(new Callback<T>() {
                    @Override
                    public void onResponse(Call<T> call, retrofit2.Response<T> response) {
                        if (!emitter.isDisposed()) {
                            if (response.isSuccessful()) {
                                emitter.onNext(response.body());
                                emitter.onComplete();

                            } else {
                                Gson gson = new Gson();
                                try {
                                    T errorResponse = gson.fromJson(response.errorBody().string(), klazz);
                                    emitter.onNext(errorResponse);
                                    emitter.onComplete();
                                } catch (IOException e) {
                                    emitter.onError(e);
                                }
                            }
                        }
                    }

                    @Override
                    public void onFailure(Call<T> call, Throwable t) {
                        if (!emitter.isDisposed()) emitter.onError(t);
                    }
                });
        }
    });
}

transforming 400-like responses into rx chain is pretty simple:

Call<Cat> request = catApi.getCat();
rxified(request, Cat.class).subscribe( (cat) -> println(cat) );

Answer 5

You can do it in your onResponse method, remember 400 is a response status not an error:

if (response.code() == 400) {              
    Log.v("Error code 400",response.errorBody().string());
}

And you can handle any response code except 200-300 with Gson like that:

if (response.code() == 400) {
   Gson gson = new GsonBuilder().create();
   ErrorPojoClass mError=new ErrorPojoClass();
   try {
       mError= gson.fromJson(response.errorBody().string(),ErrorPojoClass.class);
       Toast.makeText(context, mError.getDescription(), Toast.LENGTH_LONG).show();
   } catch (IOException e) {
       // handle failure to read error
   }        
}

Add this to your build.gradle : compile 'com.google.code.gson:gson:2.7'

If you want create Pojo class go to Json Schema 2 Pojo and paste your example Json response. Select source type Json and annotation Gson .

Answer 6

public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
    DialogHelper.dismiss();

    if (response.isSuccessful()) {
        // Success
    } else {
        try {
            JSONObject jObjError = new JSONObject(response.errorBody().string());
            Toast.makeText(getContext(), jObjError.getString("message"), Toast.LENGTH_LONG).show();
        } catch (Exception e) {
            Toast.makeText(getContext(), e.getMessage(), Toast.LENGTH_LONG).show();
        }
    }
}