How to reverse transform request from json api to proper data?

I am using Lumen + Dingo + Ember JS
I am able to transform the response into JSON API. But when I post back the data from Ember, is it in same json api format. So I want to know is there any way to deform the json api data ?

`data":{"attributes":{"size":2},"relationships":{"page":{"data":{"type":"pages","id":"2"}}},"type":"rows"}}`

From above response, i want to get `size=2, pageId=2
I have properly used relationship in Lumen models.

Any idea, how can I achieve this?