Ruby-on-rails Rails：around_* 回调
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Rails: around_* callbacks
提问by gjb
I have read the documentation at http://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html, but don't understand when the around_*callbacks are triggered in relation to before_*and after_*.
我已阅读http://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html 上的文档，但不明白何时around_*触发与before_*和相关的回调after_*。
Any help much appreciated.
非常感谢任何帮助。
Thanks.
谢谢。
回答by Jacob Relkin
around_*callbacks are invoked beforethe action, then when you want to invoke the action itself, you yieldto it, then continue execution. That's why it's called around
around_*回调在动作之前被调用，然后当你想调用动作本身时，你要调用yield它，然后继续执行。这就是为什么它被称为around
The order goes like this: before, around, after.
顺序是这样的：before, around, after。
So, a typical around_savewould look like this:
所以，一个典型的around_save看起来像这样：
def around_save
#do something...
yield #saves
#do something else...
end
回答by Pan Thomakos
The around_* callback is called around the action and inside the before_* and after_* actions. For example:
围绕动作和 before_* 和 after_* 动作内部调用 around_* 回调。例如：
class User
def before_save
puts 'before save'
end
def after_save
puts 'after_save'
end
def around_save
puts 'in around save'
yield # User saved
puts 'out around save'
end
end
User.save
before save
in around save
out around save
after_save
=> true
