ruby-on-rails - 计数器缓存更新后调用方法

Question

每当更新计数器缓存时，Rails 中有没有办法调用函数？

Answer 1

没有办法开箱即用。您可以轻松地制作一个添加该功能的 Gem。从 after_create 和 after_destroy 回调手动更新计数器可能更容易，这也可以执行您需要的任何其他代码。

例如：

class Parent
  has_many :kids
  # The parents table has a `kids_counter` column which acts as a counter cache.
end

class Kid
  belongs_to :parent
  after_create :hello
  after_destroy :goodbye

  def hello
    Parent.increment_counter(:kids_counter, parent_id)
    # Execute anything else you need here.
  end

  def goodbye
    Parent.decrement_counter(:kids_counter, parent_id)
    # Execute anything else you need here.
  end
end