Mongoid 3 回调：before_upsert 与 before_save

Question

对于 Mongoid 3+，是否有各种回调的图表/描述？ http://mongoid.org/en/mongoid/v3/callbacks.html

例如，before_upsert 与 before_save 之间有什么区别。 save 不是由insert 或update 调用引起的吗？还是save 也被destroy 调用？

另外，before_xxx 和 around_xxx 有什么区别？

干杯，

Answer 1

使用 before_xxx 代码在动作之前执行，而使用 around_xxx 您可以选择在动作本身之前和之后执行代码。

例如，假设您想在销毁用户项目（用户 has_many :proyects 和项目所属用户）后更新所有用户财产：

class ProjectsController < ApplicationController

  around_destroy :destroy_belongings

  def destroy_belongings
    old_user = self.user
    ...
    # Here the before_destroy ends.

    yield # Here the destroy is performed itself.

    # Here the after_destroy starts. It's needed to do this operation after destroy the project because, imagine, the update_belongings method calculates something related to the current number of proyects. And a simple after_destroy is not useful as we would have lost the project owner.

    old_user.update_belongings
  end
end

您还可以看到相关答案here和here。此外this other article 可能对你有用。