Rails将验证放在模块mixin中？

Question

在我的模型中,一些验证是重复的:

validates :name, :length => { :minimum => 2 }, :presence => true, :uniqueness => true
validates :name_seo, :length => { :minimum => 2 }, :presence => true, :uniqueness => true

我怎么把它放在mixin中？如果我把它们放在mixin中,我会收到这个错误

app/models/validations.rb:5: undefined method `validates' for Validations:Module (NoMethodError)

Answer 1

module Validations
  extend ActiveSupport::Concern

  included do
    validates :name, :length => { :minimum => 2 }, :presence => true, :uniqueness => true
    validates :name_seo, :length => { :minimum => 2 }, :presence => true, :uniqueness => true
  end
end

该validates宏必须在包入的予以评价,而不是模块的(就像你可能在做).

Answer 2

你的模块应该是这样的:

module CommonValidations
  extend ActiveSupport::Concern

  included do
    validates :name, :length => { :minimum => 2 }, :presence => true, :uniqueness => true
    validates :name_seo, :length => { :minimum => 2 }, :presence => true, :uniqueness => true
  end
end

然后在你的模型中:

class Post < ActiveRecord::Base
  include CommonValidations

  ...
end

我在这里使用ActiveSupport :: Concern使代码更清晰一些.