Form Object Example

form_object.rb

# used to share results from one user to another
# ensures that valid data is supplied and errors out if the parameters are invalid
class BookingFormModel
  include ActiveModel::Model

  attribute :first_name, :string
  attribute :last_name, :string
  attribute :stay_duration_days, :integer

  def persisted?
    false
  end

  def save
    @success = false

    ActiveRecord::Base.transaction do
      customer = Customer.new(customer_attributes)
      booking = Booking.new(booking_attributes)

      unless booking.save
        flush_errors(booking)
        raise ActiveRecord::RecordInvalid.new(booking)
      end

      unless customer.save
        flush_errors(customer)
        raise ActiveRecord::RecordInvalid.new(customer)
      end

      @success = true
    end

    @success
  end

  private

  def flush_errors(model)
    model.errors.each do |attribute, errors|
      if respond_to?(attribute)
        errors.each{ |error| errors.add(attribute, error) }
      else
        errors.each{ |error| errors.add(:base, error) }
      end
    end
  end

  def customer_attributes
    attributes.slice(:first_name, :first_name)
  end

  def booking_attributes
    attributes.slice(:stay_duration_days)
  end
end