engine/lib/locomotive/action_controller/responder.rb

module Locomotive
  module ActionController
    class Responder < ::ActionController::Responder

      include ::Responders::FlashResponder

      # by default flash_now messages if the resource has errors
      def set_flash_now?
        super || has_errors?
      end

      def to_json
        if get?
          display resource
        elsif has_errors?
          with_flash_message(:alert) do
            display resource.errors, :status => :unprocessable_entity
          end
        elsif post?
          in_header = controller.request.headers['X-Flash'] == 'true'
          with_flash_message(:notice, in_header) do
            display resource, :location => api_location
          end
        elsif put?
          with_flash_message do |message|
            display resource, :status => :ok, :location => api_location
          end
        elsif delete?
          with_flash_message do |message|
            display resource, :status => :ok, :location => api_location
          end
        elsif has_empty_resource_definition?
          display empty_resource, :status => :ok
        else
          with_flash_message do
            head :ok
          end
        end
      end

      protected

      def with_flash_message(type = :notice, in_header = true)
        if in_header
          set_flash_message!
          message = controller.flash[type]

          unless message.blank?
            controller.headers['X-Message']       = message
            controller.headers['X-Message-Type']  = type.to_s
          end

          yield if block_given?

          controller.flash.discard # reset flash messages !
        else
          set_flash_message!

          yield if block_given?
        end
      end

    end
  end
end