missing_record_handler.rb

module MissingRecordHandler
  extend ActiveSupport::Concern

  included do
    rescue_from ActiveRecord::RecordNotFound, :with => :render_404
  end

  module InstanceMethods
    def record_not_found
      raise ActiveRecord::RecordNotFound
    end

  private

    def render_404(exception=nil)
      logger.info "Rendering 404 with exception: #{exception.message}" if exception.present?

      respond_to do |format|
        format.html { render :file => "#{Rails.root}/public/404.html", :status => :not_found, :layout => false }
        format.json { render :text => 'Not Found', :status => :not_found }
        format.xml  { head :not_found }
        format.any  { head :not_found }
      end
    end
  end
end