Rails的模型验证条件allow_nil？ [英] Rails Model Validation Conditional allow_nil?

问题描述

所以我在想，如果我们能有一个铁轨模型验证条件allow_nil选项。

So I was wondering if we can have a conditional allow_nil option for a validation on a rails model.

我想这样做是为了能够根据一些逻辑allow_nil（其他属性）

What I would like to do is to be able to allow_nil depending upon some logic(some other attribute)

所以，我有可以保存为草稿产品模型。当被保存为草稿的价格可以是零，但不是选秀保存的价格应该是数值。我怎样才能做到这一点。下面似乎不工作。它适用于案件草案，但允许零，即使状态不起草。

So I have a product model which can be saved as draft. and when being saved as draft the price can be nil, but when not a draft save the price should be numerical. how can I achieve this. The following doesn't seem to work. It works for draft case but allows nil even when status isn't draft.

class Product<ActiveRecord::Base
   attr_accessible :status, price
   validates_numericality_of :price, allow_nil: :draft?

   def draft?
     self.status == "draft"
   end

end

看着铁轨文档我看起来像没有通过一个方法allow_nil的选择吗？

Looking at rails docs I looks like there isn't an option to pass a method to allow_nil?

一种可能的解决方案是做单独的验证对于两种情况

One possible solution is to do separate validations for both cases

 with_options :unless => :draft? do |normal|
    normal.validates_numericality_of :price
 end

 with_options :if => :draft? do |draft|
   draft.validates_numericality_of :price, allow_nil: true
 end

任何其他的方式来得到这个工作？

Any other ways to get this working ?

感谢

推荐答案

您可以使用如果和除非来请执行下列操作

You can use if and unless to do the following

class Product<ActiveRecord::Base
   attr_accessible :status, price
   validates_numericality_of :price, allow_nil: true, if: :draft?
   validates_numericality_of :price, allow_nil: false, unless: :draft?

   def draft?
     self.status == "draft"
   end

end

通过上面的，你将有2个验证设置，一个适用于当草案？ ==真，这将使尼尔斯，和一个其中草案？ ==假这不会让尼尔斯

With the above, you will have 2 validations set up, one that applies when draft? == true, which will allow nils, and one where draft? == false which will not allow nils

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