Mongoid3回调: before_upsert vs. 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和before_save之间的区别是什么。save不是由insert或update调用引起的吗？或者destroy也会调用save

另外，before_xxx和around_xxx之间有什么不同

干杯,

Answer 1

在before_xxx中，代码在动作之前执行，而在around_xxx中，您可以选择在动作之前和之后执行代码。

例如，假设您想要在销毁一个用户项目(用户项目:proyects和belongs_to has_many User)后更新所有用户资产：

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

您还可以查看相关答案here和here。此外，this other article可能对您很有用。