Retrofit 2.0 como obter resposta de erro desserializada.body

Estou usando o Retrofit 2.0.0-beta1 .

Nos testes, tenho um cenário alternativo e espero o erro HTTP 400

Eu gostaria de ter retrofit.Response<MyError> response masresponse.body() == null

MyError não é desserializado - só o vejo aqui

response.errorBody().string()

mas não me dá MyError como objeto

Atualmente, uso uma implementação muito fácil, que não requer o uso de conversores ou classes especiais. O código que eu uso é o seguinte:

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

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

ErrorResponse é seu objeto de resposta personalizado

Kotlin

val gson = Gson()
val type = object : TypeToken<ErrorResponse>() {}.type
var errorResponse: ErrorResponse? = gson.fromJson(response.errorBody()!!.charStream(), type)

Java

Gson gson = new Gson();
Type type = new TypeToken<ErrorResponse>() {}.getType();
ErrorResponse errorResponse = gson.fromJson(response.errorBody.charStream(),type);

Eu resolvi isso por:

 if(!response.isSuccessful()){
       Gson gson = new Gson();
       MyErrorMessage message=gson.fromJson(response.errorBody().charStream(),MyErrorMessage.class);
       if(message.getCode()==ErrorCode.DUPLICATE_EMAIL_ID_CODE){
                  //DO Error Code specific handling                        
        }else{
                 //DO GENERAL Error Code Specific handling                               
        }
    }

Classe MyErrorMessage:

  public class MyErrorMessage {
     private int code;
     private String message;

     public int getCode() {
        return code;
     }

     public void setCode(int code) {
        this.code = code;
     }

     public String getMessage() {
         return message;
     }

     public void setMessage(String message) {
        this.message = message;
     }
   }

No Retrofit 2.0 beta2, é desta maneira que estou recebendo respostas de erro:

1. Síncrono

   try {
      Call<RegistrationResponse> call = backendServiceApi.register(data.in.account, data.in.password,
              data.in.email);
      Response<RegistrationResponse> response = call.execute();
      if (response != null && !response.isSuccess() && response.errorBody() != null) {
          Converter<ResponseBody, BasicResponse> errorConverter =
                  MyApplication.getRestClient().getRetrofitInstance().responseConverter(BasicResponse.class, new Annotation[0]);
          BasicResponse error = errorConverter.convert(response.errorBody());
          //DO ERROR HANDLING HERE
          return;
      }
      RegistrationResponse registrationResponse = response.body();
      //DO SUCCESS HANDLING HERE
   } catch (IOException e) {
      //DO NETWORK ERROR HANDLING HERE
   }

2. Assíncrono

   Call<BasicResponse> call = service.loadRepo();
   call.enqueue(new Callback<BasicResponse>() {
       @Override
       public void onResponse(Response<BasicResponse> response, Retrofit retrofit) {
           if (response != null && !response.isSuccess() && response.errorBody() != null) {
               Converter<ResponseBody, BasicResponse> errorConverter =
                   retrofit.responseConverter(BasicResponse.class, new Annotation[0]);
               BasicResponse error = errorConverter.convert(response.errorBody());
               //DO ERROR HANDLING HERE
               return;
           }
           RegistrationResponse registrationResponse = response.body();
           //DO SUCCESS HANDLING HERE
       }
   
       @Override
       public void onFailure(Throwable t) {
           //DO NETWORK ERROR HANDLING HERE
       }
   });

Atualização para o Retrofit 2 beta3:

1. Síncrono - não alterado

2. Assíncrono - O parâmetro Retrofit foi removido do onResponse

   Call<BasicResponse> call = service.loadRepo();
   call.enqueue(new Callback<BasicResponse>() {
       @Override
       public void onResponse(Response<BasicResponse> response) {
           if (response != null && !response.isSuccess() && response.errorBody() != null) {
               Converter<ResponseBody, BasicResponse> errorConverter =
                   MyApplication.getRestClient().getRetrofitInstance().responseConverter(BasicResponse.class, new Annotation[0]);
               BasicResponse error = errorConverter.convert(response.errorBody());
               //DO ERROR HANDLING HERE
               return;
           }
           RegistrationResponse registrationResponse = response.body();
           //DO SUCCESS HANDLING HERE
       }
   
       @Override
       public void onFailure(Throwable t) {
           //DO NETWORK ERROR HANDLING HERE
       }
   });

Em https://stackoverflow.com/a/21103420/2914140 e https://futurestud.io/tutorials/retrofit-2-simple-error-handling, essa variante é mostrada no Retrofit 2.1.0.

call.enqueue(new Callback<MyResponse>() {
    @Override
    public void onResponse(Call<MyResponse> call, Response<MyResponse> response) {
        if (response.isSuccessful()) {
            ...
        } else {
            Converter<ResponseBody, MyError> converter
                    = MyApplication.getRetrofit().responseBodyConverter(
                    MyError.class, new Annotation[0]);
            MyError errorResponse = null;
            try {
                errorResponse = converter.convert(response.errorBody());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

 @Override
 public void onResponse(Call<Void> call, retrofit2.Response<Void> response) {
            if (response.isSuccessful()) {

            //Do something if response is ok
            } else {

                JsonParser parser = new JsonParser();
                JsonElement mJson = null;
                try {
                    mJson = parser.parse(response.errorBody().string());
                    Gson gson = new Gson();
                    MyError errorResponse = gson.fromJson(mJson, MyError.class);
                } catch (IOException ex) {
                    ex.printStackTrace();
                }

            }

Crie um modelo da resposta a erros e do usuário Gson para converter a resposta. Isso vai funcionar bem.

APIError.java

public class APIError {
    private String message;

    public String getMessage() {
        return message;
    }
}

MainActivity.java (dentro da solicitação onResponse)

if (response.isSuccessful()) {
    // Do your success stuff...

} else {
    APIError message = new Gson().fromJson(response.errorBody().charStream(), APIError.class);
    Toast.makeText(MainActivity.this, "" + message.getMessage(), Toast.LENGTH_SHORT).show();
}

Fiz dessa maneira para chamadas assíncronas usando o Retrofit 2.0-beta2:

@Override
public void onResponse(Response<RegistrationResponse> response, 
                       Retrofit retrofit) {
    if (response.isSuccess()) {
        // Do success handling here
    } else {
        try {
            MyError myError = (MyError)retrofit.responseConverter(
                    MyError.class, MyError.class.getAnnotations())
                .convert(response.errorBody());
            // Do error handling here
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Se você usar o Kotlin, outra solução pode ser apenas criar a função de extensão para a classe Response:

inline fun <reified T>Response<*>.parseErrJsonResponse(): T?
{
    val moshi = MyCustomMoshiBuilder().build()
    val parser = moshi.adapter(T::class.java)
    val response = errorBody()?.string()
    if(response != null)
        try {
            return parser.fromJson(response)
        } catch(e: JsonDataException) {
            e.printStackTrace()
        }
    return null
}

Uso

val myError = response.parseErrJsonResponse<MyErrorResponse>()
if(myError != null) {
   // handle your error logic here
   // ...
}

Na verdade, é muito direto.

Kotlin:

val jsonObj = JSONObject(response.errorBody()!!.charStream().readText())
responseInterface.onFailure(jsonObj.getString("msg"))

Java:

JSONObject jsonObj = new JSONObject(response.errorBody().charStream().readText());
responseInterface.onFailure(jsonObj.getString("msg"));

Testado em retrofit: 2.5.0. Leia o texto do charStream que fornecerá uma String e analise JSONObject.

Adios.

Eu estava enfrentando o mesmo problema. Eu o resolvi com o retrofit. Deixe-me mostrar isso ...

Se sua estrutura JSON de erro for como

{
"error": {
    "status": "The email field is required."
}
}


My ErrorRespnce.java 

public class ErrorResponse {

   @SerializedName("error")
   @Expose
   private ErrorStatus error;

   public ErrorStatus getError() {
      return error;
   }

   public void setError(ErrorStatus error) {
      this.error = error;
   }
}

E essa é minha classe de status de erro

public class ErrorStatus {

  @SerializedName("status")
  @Expose
  private String status;

  public String getStatus() {
      return status;
  }

  public void setStatus(String status) {
      this.status = status;
  }
}

Agora precisamos de uma classe que possa lidar com nosso json.

  public class ErrorUtils {

   public static ErrorResponse parseError (Response<?> response){
      Converter<ResponseBody , ErrorResponse> converter =          ApiClient.getClient().responseBodyConverter(ErrorResponse.class , new Annotation[0]);
    ErrorResponse errorResponse;
    try{
        errorResponse = converter.convert(response.errorBody());
    }catch (IOException e){
        return new ErrorResponse();
    }
    return errorResponse;
}
}

Agora, podemos verificar nossa resposta em retrofit call api

private void registrationRequest(String name , String email , String password , String c_password){


    final Call<RegistrationResponce> registrationResponceCall = apiInterface.getRegistration(name , email , password , c_password);
    registrationResponceCall.enqueue(new Callback<RegistrationResponce>() {
        @Override
        public void onResponse(Call<RegistrationResponce> call, Response<RegistrationResponce> response) {



            if (response.code() == 200){


            }else if (response.code() == 401){


                ErrorResponse errorResponse = ErrorUtils.parseError(response);
                Toast.makeText(MainActivity.this, ""+errorResponse.getError().getStatus(), Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onFailure(Call<RegistrationResponce> call, Throwable t) {

        }
    });
}

É isso agora, você pode mostrar seu brinde

Aqui está uma solução elegante usando Kotlinextensões:

data class ApiError(val code: Int, val message: String?) {
    companion object {
        val EMPTY_API_ERROR = ApiError(-1, null)
    }
}

fun Throwable.getApiError(): ApiError? {
    if (this is HttpException) {
        try {
            val errorJsonString = this.response()?.errorBody()?.string()
            return Gson().fromJson(errorJsonString, ApiError::class.java)
        } catch (exception: Exception) {
            // Ignore
        }
    }
    return EMPTY_API_ERROR
}

e uso:

showError(retrofitThrowable.getApiError()?.message)

Dessa forma, você não precisa de uma instância de Retrofit se estiver injetando apenas um serviço criado a partir de Retrofit.

public class ErrorUtils {

  public static APIError parseError(Context context, Response<?> response) {

    APIError error = new APIError();

    try {
        Gson gson = new Gson();
        error = gson.fromJson(response.errorBody().charStream(), APIError.class);
    } catch (Exception e) {
        Toast.makeText(context, e.getMessage(), Toast.LENGTH_LONG).show();
    }

    if (TextUtils.isEmpty(error.getErrorMessage())) {
        error.setError(response.raw().message());
    }
    return error;
  }
}

Use-o assim:

if (response.isSuccessful()) {

      ...

    } else {

      String msg = ErrorUtils.parseError(fragment.getActivity(), response).getError(); // would be from your error class
      Snackbar.make(someview, msg, Snackbar.LENGTH_LONG).show();
    }
  }

Esse parece ser o problema quando você usa o OkHttp junto com o Retrofit, para remover o OkHttp ou usar o código abaixo para obter o corpo do erro:

if (!response.isSuccessful()) {
 InputStream i = response.errorBody().byteStream();
 BufferedReader r = new BufferedReader(new InputStreamReader(i));
 StringBuilder errorResult = new StringBuilder();
 String line;
 try {
   while ((line = r.readLine()) != null) {
   errorResult.append(line).append('\n');
   }
 } catch (IOException e) { 
    e.printStackTrace(); 
}
}

Leia errorBody em uma String e analise manualmente json.

 if(!response.isSuccessful()) {
   
    String error = "";
    try {
        BufferedReader ereader = new BufferedReader(new InputStreamReader(
                response.errorBody().byteStream()));
        String eline = null;
        while ((eline = ereader.readLine()) != null) {
            error += eline + "";
        }
        ereader.close();
    } catch (Exception e) {
        error += e.getMessage();
    }
    Log.e("Error",error);
    
    try {
        JSONObject reader = new JSONObject(error);
        String message = reader.getString("message");
    
        Toast.makeText(context,message,Toast.LENGTH_SHORT).show();
    
    } catch (JSONException e) {
        e.printStackTrace();
    }
 }

resolvido por:

Converter<MyError> converter = 
    (Converter<MyError>)JacksonConverterFactory.create().get(MyError.class);
MyError myError =  converter.fromBody(response.errorBody());

try{
                ResponseBody response = ((HttpException) t).response().errorBody();
                JSONObject json = new JSONObject( new String(response.bytes()) );
                errMsg = json.getString("message");
            }catch(JSONException e){
                return t.getMessage();
            }
            catch(IOException e){
                return t.getMessage();
            }

Em Kotlin:

val call = APIClient.getInstance().signIn(AuthRequestWrapper(AuthRequest("1234567890z", "12341234", "nonce")))
call.enqueue(object : Callback<AuthResponse> {
    override fun onResponse(call: Call<AuthResponse>, response: Response<AuthResponse>) {
        if (response.isSuccessful) {

        } else {
            val a = object : Annotation{}
            val errorConverter = RentalGeekClient.getRetrofitInstance().responseBodyConverter<AuthFailureResponse>(AuthFailureResponse::class.java, arrayOf(a))
            val authFailureResponse = errorConverter.convert(response.errorBody())
        }
    }

    override fun onFailure(call: Call<AuthResponse>, t: Throwable) {
    }
})

Os valores errorBody devem definir o objeto APIError no Retrofit. Para que você possa usar a estrutura de código abaixo.

public class APIErrorUtils {

    public static APIError parseError(Response<?> response) {
        Converter<ResponseBody, APIError> converter = API.getClient().responseBodyConverter(APIError.class, new Annotation[0]);

        APIError error;

        try {
            error = converter.convert(response.errorBody());
            Log.d("SERVICELOG", "****************************************************");
            Log.d("SERVICELOG", "***** SERVICE LOG");
            Log.d("SERVICELOG", "***** TIMESTAMP: " + String.valueOf(error.getTimestamp()));
            Log.d("SERVICELOG", "***** STATUS: " + String.valueOf(error.getStatus()));
            Log.d("SERVICELOG", "***** ERROR: " + error.getError());
            Log.d("SERVICELOG", "***** MESSAGE: " + error.getMessage());
            Log.d("SERVICELOG", "***** PATH: " + error.getPath());
            Log.d("SERVICELOG", "****************************************************");
        } catch (IOException e) {
            return new APIError();
        }

        return error;
    }
}

APIError error = APIErrorUtils.parseError(response);
if (error.getStatus() == 400) {
    ....
}

Testado e funciona

 public BaseModel parse(Response<BaseModel> response , Retrofit retrofit){
            BaseModel error = null;
            Converter<ResponseBody, BaseModel> errorConverter =
                    retrofit.responseBodyConverter(BaseModel.class, new Annotation[0]);
            try {
                if (response.errorBody() != null) {
                    error = errorConverter.convert(response.errorBody());
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            return error;
        }

val error = JSONObject(callApi.errorBody()?.string() as String)
            CustomResult.OnError(CustomNotFoundError(userMessage = error["userMessage"] as String))

open class CustomError (
    val traceId: String? = null,
    val errorCode: String? = null,
    val systemMessage: String? = null,
    val userMessage: String? = null,
    val cause: Throwable? = null
)

open class ErrorThrowable(
    private val traceId: String? = null,
    private val errorCode: String? = null,
    private val systemMessage: String? = null,
    private val userMessage: String? = null,
    override val cause: Throwable? = null
) : Throwable(userMessage, cause) {
    fun toError(): CustomError = CustomError(traceId, errorCode, systemMessage, userMessage, cause)
}


class NetworkError(traceId: String? = null, errorCode: String? = null, systemMessage: String? = null, userMessage: String? = null, cause: Throwable? = null):
    CustomError(traceId, errorCode, systemMessage, userMessage?: "Usted no tiene conexión a internet, active los datos", cause)

class HttpError(traceId: String? = null, errorCode: String? = null, systemMessage: String? = null, userMessage: String? = null, cause: Throwable? = null):
    CustomError(traceId, errorCode, systemMessage, userMessage, cause)

class UnknownError(traceId: String? = null, errorCode: String? = null, systemMessage: String? = null, userMessage: String? = null, cause: Throwable? = null):
    CustomError(traceId, errorCode, systemMessage, userMessage?: "Unknown error", cause)

class CustomNotFoundError(traceId: String? = null, errorCode: String? = null, systemMessage: String? = null, userMessage: String? = null, cause: Throwable? = null):
    CustomError(traceId, errorCode, systemMessage, userMessage?: "Data not found", cause)`