validates exclusion of controller names when catching all routes

Of course catching all routes is bad, but if you have to:

class Account < ActiveRecord::Base
  INVALID_PAGE_NAMES = Dir[Rails.root.join('app/controllers/*_controller.rb')].map { |path| path.match(/(\w+)_controller.rb/); $1 }
  validates :page_name, :exclusion => { :in => INVALID_PAGE_NAMES,
    :message => "Page %{value} is reserved." }
end