Route Constraints, mapping Friendly Id 4.x to /:id of any model

page.rb

# app/models/page.rb
class Page < ActiveRecord::Base
  extend FriendlyId
  friendly_id :title, :use => [:slugged, :history]
end

page_constraint.rb

# config/initializers/page_constraint.rb
class PageConstraint

  # uses friendly_id 4.x
  def initialize
    @page_paths = Page.includes(:slugs).collect(&:slugs).flatten.map { |a| "/#{a.slug}" }
  end

  def matches?(request)
    @page_paths.include?(request.path)
  end

end

page_observer.rb

# app/observers/page_observer.rb
class PageObserver < ActiveRecord::Observer
  def after_save(record)
    # record is the Page#object that was just saved
    Rails.application.reload_routes!
  end
end

### NOTE:
# REMEMBER TO ADD THIS TO config/application.rb

# Include the following
# you will see some information that has already been commented out .. 

# Tell the app to look in the app/observers directory for files
# config.autoload_paths += %W(#{Rails.root}/app/observers)

# Tell the app that we have an observer now .. 
# config.active_record.observers = :page_observer

routes.rb

# config/routes.rb
AwesomeApp::Application.routes.draw do
  resources :pages
  
  root :to => 'welcome#index'
  # placed at bottom so as not to mangle other paths
  get '/:id' => 'pages#show', :as => 'public_page', :constraints => PageConstraint.new
end

What if you have some route that have the same name as a page's slug? It will render show action for the page but not that route.

I tried to add && request.params[:controller] == 'pages' to matches? but it didn't help. Any ideas?