如何在运行时创建after_save回调

我就是这样做的。在模型中,我会:

attr_accessor :after_save_callback

after_save { |record|
  record.after_save_callback.call unless record.after_save_callback.nil?
}

而绑定事件可以是:

user = User.first
user.after_save_callback = Proc.new { "actual code" }

@user = User.first

eigen = class << @user; self; end
eigen.after_save do
  puts @user.email
end

@user.save
# prints user.email


@another = User.find(100)
@another.save
# does not print user.email