Retrofit: what to do when the structure of the server response changes?

Question

Java

Hey!

I understand with API, the detailed description to which is not present.
For example, a GET request to the server: _https:_//server.net/getdetails/?ctn=4950000001
If everything is OK, a response with a 200 code will be returned:

• if the number was not transferred between operators:
  

{"code": "495", "num": "0000001", "full_num": "4950000001", "operator": "МГТС", "region": "г. Москва"}

• if there was a change of operator with the preservation of the number:
  

{"code": "900", "num": "5555555", "full_num": "9005555555", "operator": "ВымпелКом", "old_operator": "СИМ ТЕЛЕКОМ", "region": "г. Москва * Московская область"}

, the old_operator parameter is added .

If something is wrong with the input data, a response with a 404 code will be returned.
The response body will be:

• This:
  

{"info": "Неверный формат номера: 49500000", "example": ["[phone]", "74959898533", "84959898533", "4959898533"]}

• This:
  

{"info": "Номер не найден. Проверьте код города: 000", "example": ["3XX", "4XX", "8XX", "9XX"]}

• or that:
  

{"info": "Неверный формат запроса, ctn обязательный параметр", "example": "https://server.net/getdetails/?ctn=[phone]"}

How to handle server response with Retrofit? Is it possible?
As far as I understand, it (Retrofit) creates an object from the response, which I can then work with.
What to do if both the server response itself (code, content) and the format of the correct JSON response change?

Answer 1

Yes, you can live with it. Retrofit itself does not convert the response to json, for this it is given addConverterFactory(factory). You need to write a custom adapter for the json conversion library that you use (examples about Gson ). From the response, you will have to understand what exactly came and return the corresponding object.