osem-fcy/app/serializers/conference_serializer.rb

class ConferenceSerializer < ActiveModel::Serializer
  attributes :short_title, :title, :description, :start_date, :end_date, :logo,
             :difficulty_levels, :event_types, :rooms, :tracks,
             :date_range, :revision

  def difficulty_levels
    object.difficulty_levels.map do |difficulty_level| { id: difficulty_level.id,
                                                         title: difficulty_level.title,
                                                         description: difficulty_level.description
                                                       }
    end
  end

  def event_types
    object.event_types.map do |event_type| { id: event_type.id,
                                             title: event_type.title,
                                             length: event_type.length,
                                             description: event_type.description
                                           }
    end
  end

  def rooms
    object.rooms.includes(:events).map do |room| { id: room.id,
                                                   size: room.size,
                                                   events: room.events.map do |event| { guid: event.title,
                                                                                        title:  event.title,
                                                                                        subtitle: event.subtitle,
                                                                                        abstract: event.abstract,
                                                                                        description: event.description,
                                                                                        is_highlight: event.is_highlight,
                                                                                        require_registration:  event.require_registration,
                                                                                        start_time: event.start_time,
                                                                                        event_type_id: event.event_type.id,
                                                                                        difficulty_level_id: event.difficulty_level_id,
                                                                                        track_id: event.track_id,
                                                                                        speaker_names: event.speaker_names
                                                                                      }
                                                           end
                                                 }
    end
  end

  def tracks
    object.tracks.map do |track| { 'id' => track.id,
                                   'name' => track.name,
                                   'description' => track.description
                                 }
    end
  end

  def name
    object.title
  end

  def year
    object.start_date.try(:year)
  end

  def socialtag
    object.contact.social_tag
  end

  def revision
    object.revision || 0
  end

  def date_range
    if defined? object.date_range_string
        object.date_range_string.try(:split, ',').try(:first)
    end
  end
end