exception_handling.rb

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception

  unless Rails.application.config.consider_all_requests_local
    rescue_from Exception, with: lambda { |exception| Airbrake.notify(exception); render_error(500) }
    rescue_from ActionView::MissingTemplate, ActiveRecord::RecordNotFound, ActionController::RoutingError,
                ActionController::UnknownController, AbstractController::ActionNotFound, ActiveRecord::RecordNotFound,
                ActionController::UnknownFormat, with: lambda { |exception| render_error(404) }
  end

  def routing_error
    raise ActionController::RoutingError.new(params[:path])
  end

  private
    def render_error(status)
      respond_to do |format|
        format.rss { render template: "errors/error_#{status}", formats: [:html], content_type: 'text/html' }
        format.html { render template: "errors/error_#{status}" }
      end
    end
end