ruby-on-rails - 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？如果我只是将它们放入 mixin 中，我会收到此错误

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

必须在包含器的validates上下文中评估宏，而不是在模块的上下文中（就像您可能正在做的那样）。

Answer 2

您的模块应如下所示：

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来使代码更清晰一些。