json.extract! db, *Db.json_keys

json.contents do
  root = db.root_folder
  json.extract! root, *DbFolder.json_keys

  json.subfolders(root.subfolders) do |folder|
    json.extract! folder, *DbFolder.json_keys
  end

  json.streams(root.db_streams) do |stream|
    json.extract! stream, *DbStream.json_keys
    json.elements(stream.db_elements) do |element|
      json.extract! element, *DbElement.json_keys
    end
  end

end