Android: Realm + Retrofit - Serialize apiresponse

Question

Preface: I'm using Retrofit to handle my API calls and Realm(realm.io) to store the data.

The API im dealing with uses the following structure:

Array Response

{
  "response":
    [
      {
        "objectField1":"abc"
        "objectField2":"abc"
        "objectField3":"abc"
        "objectField4":"abc"
      },
      {
        "objectField1":"abc"
        "objectField2":"abc"
        "objectField3":"abc"
        "objectField4":"abc"
      }
    ]
}

Single object response

{
  "response":
    {
      "objectField1":"abc"
      "objectField2":"abc"
      "objectField3":"abc"
      "objectField4":"abc"
    }
}

All api responses are contained in a response object either in an array (if result size > 1) or an object (if result size == 1).

I currently have my API call as follows:

@GET("/api/myEndpoint")
void getAllExampleObjects(Callback<MyRealmClass> callback);

How can I serialise the API response (handling both array and single object cases) to place them in my realm?

Answer 1

Christian from Realm here. If you have a single REST API call that can return both a list and a single object, you will have to do something manually. As colriot points out you will have to write your own GSON deserializer. For ideas how to write one see a very good answer in this SO post: How to handle parameters that can be an ARRAY or OBJECT in Retrofit on Android?

To get the objects into Realm you can use realm.copyToRealm(objects) in the following way:

@GET("/api/myEndpoint")
void getAllExampleObjects(Callback<List<MyRealmClass>> callback);

Callback callback = new Callback() {
    @Override
    public void success(List<MyRealmClass> objects, Response response) {
      realm.beginTransaction();
      realm.copyToRealm(objects);
      realm.commitTransaction();
    }

    @Override
    public void failure(RetrofitError retrofitError) {

    }
};