movie_sweeper.rb

class MovieSweeper < ActionController::Caching::Sweeper
  observe Movie
  # if a movie is created or deleted, movie list becomes invalid
  #   and rendered partials become invalid
  def after_save(movie)    ; invalidate ; end
  def after_destroy(movie) ; invalidate ; end
  private
  def invalidate
    expire_action :action => ['index', 'show']
    expire_fragment 'movies_with_ratings'
  end
end

# IMPORTANT: must add following to top of MoviesController:
cache_sweeper :movie_sweeper
caches_action :index, :show