如何在Rails中编写条件验证？

Question

Let's say I have a model, Post.rb:

validates :title => true
validates :post => true, :length => { :maximum => 220 } 
validate :custom_validation

def custom_validation 
   ...
end

I want to run the validtions for title, post, and the custom_validation ONLY if another attribute, draft, is false. (ie ignore when draft is true).

How can I do this?

Answer 1

validates :title => true, :unless => :draft