rescue_from

Rescue exceptions raised in controller actions.

rescue_from receives a series of exception classes or class names, and a trailing :with option with the name of a method or a Proc object to be called to handle them. Alternatively a block can be given.

Handlers that take one argument will be called with the exception, so that the exception can be inspected when dealing with it.

Handlers are inherited. They are searched from right to left, from bottom to top, and up the hierarchy. The handler of the first class for which exception.is_a?(klass) holds true is the one invoked, if any.

  class ApplicationController < ActionController::Base
    rescue_from User::NotAuthorized, :with => :deny_access # self defined exception
    rescue_from ActiveRecord::RecordInvalid, :with => :show_errors

    rescue_from 'MyAppError::Base' do |exception|
      render :xml => exception, :status => 500
    end

    protected
      def deny_access
        ...
      end

      def show_errors(exception)
        exception.record.new_record? ? ...
      end
  end