internal_redirect_to.rb

class ApplicationController < ActionController::Base
 
protected

  # Protected: Internally redirects and renders a request.
  #
  # Example: 
  #
  # def latest
  #   post = Post.last
  #   internal_redirect_to controller: 'posts', action: 'show', id: post.id
  # end
  #
  def internal_redirect_to(options={})
    controller_name  = "#{params[:controller]}_controller".classify
    controller_klass = controller_name.constantize

    # Set up the instance with the request, response and also the parameters.
    controller_instance = controller_klass.new.tap do |c|
      c.request  = request
      c.response = response

      c.request.params.merge!(options)
    end

    controller_instance.process(params[:action])
  end
end