grape-entity example

base_entity.rb

# app/presenters/api/v1/base_entity.rb
module Api
  module V1
    module BaseEntity < Grape::Entity
      format_with(:unix_timestamp) { |dt| dt.to_time.to_i }
    end
  end
end

status_detailed_entity.rb

# app/presenters/api/v1/status_detailed_entity.rb
module API
  module V1
    class StatusDetailedEntity < API::V1::StatusDetailed
      expose :internal_id
    end
  end
end

status_entity.rb

# app/presenters/api/v1/status_entity.rb
module Api
  module V1
    class StatusEntity < Api::V1::BaseEntity
      expose :user_name
      expose :text, documentation: { type: "String", desc: "Status update text." }
      expose :ip, if: { type: :full }
      expose :user_type, :user_id, if: lambda { |status, options| status.user.public? }
      expose :contact_info do
        expose :phone
        expose :address, using: API::V1::AddressEntity
      end
      expose :digest do |status, options|
        Digest::MD5.hexdigest status.txt
      end
      expose :replies, using: API::V1::StatusEntity, as: :replies
      expose :last_reply, using: API::V1::StatusDetailedEntity do |status, options|
        status.replies.last
      end

      with_options(format_with: :unix_timestamp) do
        expose :created_at
        expose :updated_at
      end
    end
  end
end