基于 Mongoid 中的父条件验证子属性

Question

如果父文档中的属性为真或假，我正在尝试根据条件validate_presence_of 子属性。请在下面查看我的模型：

class Venue
  include Mongoid::Document

  field :name, type: String
  field :has_locations, type: Mongoid::Boolean

  embeds_many :locations
  accepts_nested_attributes_for :locations
end

还有子（嵌入式）模型。

class Location
  include Mongoid::Document

  field :city

  embedded_in :venue, inverse_of: :locations

  # Here I want to validate presence of :city, but only if
  # :has_locations in Venue is true
  validates_presence_of :city, if: ????

end

然后我有一个带有:has_locations 和fields_for 复选框的表单，用于嵌套位置属性。我的视图和控制器都设置好了，我想我只是不明白如何在模型中进行这种子父条件验证。任何帮助表示赞赏！

Answer 1

经过更多的修改，我能够像这样实现所需的功能，不确定是否是最好的方法，但它就是这样，尽管现在还有一个自定义错误消息的新问题。我的模型现在看起来像这样：

class Venue
  include Mongoid::Document

  field :name, type: String
  field :has_locations, type: Mongoid::Boolean

  embeds_many :locations
  accepts_nested_attributes_for :locations, reject_if: :no_location_required

  private

  def no_location_required
    has_locations == false
  end
end

和

class Location
  include Mongoid::Document

  field :city

  embedded_in :venue, inverse_of: :locations

  validates_presence_of :city

end

现在这似乎可行，但由于某种原因显示的验证错误消息是通用的：“位置无效”。我希望它返回“需要城市”。我尝试在en.yml 中处理错误消息，但至今无济于事。

Answer 2

您可以使用validates_associated。这将验证关联的对象是否都有效。

所以这会转到您的父模型，例如：

class Venue
 include Mongoid::Document

 field :name, type: String
 field :has_locations, type: Mongoid::Boolean

 embeds_many :locations
 accepts_nested_attributes_for :locations

 #validate the associated locations if has_locations is checked (or true)
 validates_associated :locations, if: Proc.new { |venue| venue.has_locations }
end

现在，添加您想在位置模型中添加的任何常规验证：

class Location
 include Mongoid::Document

 field :city

 embedded_in :venue, inverse_of: :locations

 # Here I want to validate presence of :city
 validates_presence_of :city
 #Never use validates_associated :venue here if we have already use it in the associated model, otherwise will be a circular dependency and cause infinite recursion.
end