Polymorphic RESTful response

article-response.json

{
  "article": {
    "title": "Hello world",
    "body": [{
        "type": "text",
        "text": "Hi there"
      }, {
        "type": "image",
        "source": "https://example.com/hello-world-banner.jpg",
        "author": "John Doe",
        "description": "Hello World! banner"
      }, {
        "type": "video",
        "source": "http://mirrorblender.top-ix.org/peach/bigbuckbunny_movies/big_buck_bunny_1080p_surround.avi",
        "thumbnail": "https://peach.blender.org/wp-content/uploads/dl_1080p.jpg",
        "title": "Big Buck Bunny",
        "duration": 574
      }
    ]
  }
}