Ability to filter nested fields in datasource

[mingard]

Currently, I'm unable to filter specific fields of a Reference object. Either, or both of the following would be great.

Options 1: dot notation

{
  "datasource": {
    "key": "books",
    "name": "Books",
    "source": {
      "endpoint": "1.0/publisher/books"
    },
    "paginate": 1,
    "count": 1,
    "fields": {
      "title": 1,
      "lead_image.url": 1,
      "lead_image.title": 1
    }
  }
}

Options 1: nested params

{
  "datasource": {
    "key": "books",
    "name": "Books",
    "source": {
      "endpoint": "1.0/publisher/books"
    },
    "paginate": 1,
    "count": 1,
    "fields": {
      "title": 1,
      "lead_image": {
        "title": 1,
        "url": 1
      } 
    }
  }
}

[jimlambie]

Should already be possible - will investigate