在 Rails 中包含模塊

Question

考慮多個具有重疊字段和功能的 ActiveRecord 類，並且其中許多重疊字段具有相同的驗證。 我正在嘗試共享驗證，但如果滿足條件（基於模型的非重疊屬性之一），則不運行共享代碼。

class Book < ApplicationRecord
  include SharedValidation
end

class Magazine < ApplicationRecord
  include SharedValidation
end

module SharedValidation
  extend ActiveSupport::Concern
  include ActiveModel::Validations

  validates_presence_of :name, :publisher, :author
end

所以假設Magazine.is_deleted是一個 Magazine-only 字段，我們只想在 is_deleted 為false 時運行共享驗證。 關於如何在課堂上實現這一點的任何想法？

---

注意：我嘗試通過執行字段檢測和評估來修改模塊，但不確定這是否有意義或是否有效：

module SharedValidation
  extend ActiveSupport::Concern
  include ActiveModel::Validations

  included do
    proc do |rcd|
      has_deleted_field = self.column_names.include?('is_deleted') 
      
      if (has_deleted_field && !rcd.is_deleted) || !has_deleted_field
        validates_presence_of :name, :publisher, :author
      end 
    end
  end
end

Answer 1

看起來您可以將條件添加到驗證方法中（在 SharedModule 中），而不是有條件地包含模塊。

使用您的樣品：

class Book < ApplicationRecord
  include SharedValidations
end

class Magazine < ApplicationRecord
  include SharedValidations
end

module SharedValidations
  extend ActiveSupport::Concern
  include ActiveModel::Validations

  def deleted
    return unless self.class.column_names.include?("is_deleted")

    is_deleted
  end

  included do
    validates :name, :publisher, presence: true, unless: :deleted
  end
end

Magazine 有name 、 publisher和is_deleted列。 Book 只有name ， publisher沒有is_deleted 。

看起來這個設置有效。

irb> book = Book.new()
=> #<Book id: nil, name: nil, publisher: nil, created_at: nil, updated_at: nil>
irb> book.valid?
=> false
irb> book.errors.full_messages
=> ["Name can't be blank", "Publisher can't be blank"]

irb> magazine = Magazine.new
=> #<Magazine id: nil, name: nil, publisher: nil, is_deleted: nil, created_at: nil, updated_at: nil>
irb> magazine.valid?
=> false
irb> magazine.errors.full_messages
=> ["Name can't be blank", "Publisher can't be blank"]

irb> magazine.is_deleted=true
=> true
irb> magazine.valid?
=> true