Rails 3 Transactions，回滾一切

Question

class Bear < ActiveRecord::Base 
    def feed! 
     self.transaction do 
      raise Exception unless self.foods_eaten << Food.new(:name => "fish") 
      self.fed_at = Time.now 
      save! 
     end 
    end 
end 

class Hippo < ActiveRecord::Base 
    def wash! 
     self.transaction do 
      @soap.inventory -= 1 
      @soap.save! 
      self.washed_at = Time.now 
      save! 
     end 
    end 
end 

class ZookeeperController < ApplicationController 

    def chores 
     @zookeeper = Zookeeper.find(params[:id]) 
     Animal.transaction do 
      begin 
       @hippo.wash! 
       @bear.feed! # => FAIL AT THIS LINE 
       @zookeeper.finished_at = Time.now 
       @zookeeper.save! 
       redirect_to chores_completed_path 
      rescue Exception => e 
       render "new_chores" 
      end 
     end 
    end 
end 

如果Zookeeper#chores被調用且@bear.feed!失敗並引發異常，那麼將所有的回滾？

對於如何改進此代碼的任何其他建議也是受歡迎的。

Answer 1

看來我必須做的是手動引發ActiveRecord :: Rollback，否則它將無法按預期工作。 ActiveRecord ::回滾是唯一一個不會導致你的屏幕轉儲。 http://api.rubyonrails.org/classes/ActiveRecord/Rollback.html

它是有道理的，它會這樣工作，但不是真的我直覺上認爲它會工作。如果我錯了，請糾正我。

因此，新的代碼將是這個樣子：

class ZookeeperController < ApplicationController 

    def chores 
     @zookeeper = Zookeeper.find(params[:id]) 
     Animal.transaction do 
      begin 
       @hippo.wash! 
       @bear.feed! # => FAIL AT THIS LINE 
       @zookeeper.finished_at = Time.now 
       @zookeeper.save! 
       redirect_to chores_completed_path 
      rescue Exception => e 
       @_errors = true 
       render "new_chores" 
      end 
      raise ActiveRecord::Rollback if @_errors 
     end 
    end 
end