movie_sweeper.rb

class MovieSweeper < ActionController::Caching::Sweeper
  observe Movie
  # if a movie is created or deleted, movie list becomes invalid
  def after_create(movie)  ; expire_action :action => 'index' ;  end
  def after_destroy(movie) ; expire_action :action => 'index' ;  end
  # if a movie is updated, its cached 'show' view becomes invalid
  def after_update(movie) ; expire_fragment movie_path(movie) ; end
end

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