Rails. Access to flash messages from lib classes

application_controller.rb

class ApplicationController < ActionController::Base
  before_filter :globalize_session, :error_to_flash
  
  protected
  
   def globalize_session
    Thread.current[:session] = session
  end
  
  def error_to_flash
    if session[:error].present?
      flash[:warning] = session.delete(:error)
    end
  end
end

some_class.rb

class SomeClass
  def initialize(error = nil)
    if Thread.current[:session].present?
      Thread.current[:session][:error] = error
    end
  end
end