application.rb

%w( observers sweepers ).each do |dir|
    config.autoload_paths << "#{Rails.root}/app/#{dir}"
end

development.rb

config.action_controller.perform_caching = true

app/sweepers下 category_sweeper.rb

class CategorySweeper < ActionController::Caching::Sweeper
  observe Category

  def after_create(category)
    puts "enter after_create now..."
    expire_cache_for(category)
  end

  def after_update(category)
    expire_cache_for(category)
  end

  def after_destroy(category)
    expire_cache_for(category)
  end

  private
  def expire_cache_for(category)
    expire_fragment("side_user_categories_#{category.user.id}")
  end
end

app/views/shared/_side_user.html.slim

- cache("side_user_categories_#{@user.id}") do
  - categories_ = user_categories
  - categories_.each do |category|
      = link_to category.name, category

代码如上，现在问题是：当我对 Category 进行 create,update,destroy 操作时，Sweeper 里的那些方法（after_create，after_update，after_destroy）没有被调用，方法没进去。 求解，感谢！