gistfile1.rb

# To add a folder for sweepers
# /config/environment.rb

config.load_paths += %W( #{RAILS_ROOT}/app/sweepers )

# The Typical Sweeper
# /app/sweepers/post_sweeper.rb

class PostSweeper < ActionController::Caching::Sweeper
  observe Post
  
  def after_save(post)
    clear_posts_cache(post)
  end
  
  def after_destroy(post)
    clear_posts_cache(post)
  end
  
  def clear_posts_cache(post)
    expire_page :controller => :posts, 
                :action => :index
    expire_page :controller => :posts, 
                :action => :show, 
                :id => post
  end
end