ruby-on-rails - rails : Using form fields that are unassociated with a model in validations

Question

在 Ruby on Rails 应用程序中，我尝试使用来自与验证模型无关的字段的信息。

这里以模型的一部分为例(整个模型有点大):

class Scorecard < ActiveRecord::Base
  belongs_to :course
  belongs_to :user

  validate :attributes_consistency

  def attributes_consistency
    # Executed for all scorecards.  Checks if the user completed the hole attributes correctly
    if ( params[:no_fairways] and any_fairways? and !only_nine? ) or ( params[:no_fairways] and !any_h1_to_h9_score_blank and any_h1_to_h9_fairway? and only_nine? ) or ( params[:no_fairways] and !any_h10_to_h18_score_blank and any_h10_to_h18_fairway? and only_nine? )
      errors.add_to_base("You inidicated that you missed all the fairways, but you also marked one or more fairways in the scorecard.  Either uncheck the fairways mistakenly marked or uncheck the 'No fairways' checkbox.")
    end
    if ( params[:no_girs] and any_girs? and !only_nine? ) or ( params[:no_girs] and !any_h1_to_h9_score_blank and any_h1_to_h9_gir? and only_nine? ) or ( params[:no_girs] and !any_h10_to_h18_score_blank and any_h10_to_h18_gir? and only_nine? )
      errors.add_to_base("You inidicated that you missed all the greens, but you also marked one or more greens in the scorecard.  Either uncheck the marked greens on the scorecard or uncheck the 'No GIRs' checkbox.")
    end
  end # attributes_consistency


  def any_h1_to_h9_score_blank?
    h1_score.blank? or h2_score.blank? or h3_score.blank? or h4_score.blank? or h5_score.blank? or h6_score.blank? or h7_score.blank? or h8_score.blank? or h9_score.blank?
  end
  def any_h10_to_h18_score_blank?
    h10_score.blank? or h11_score.blank? or h12_score.blank? or h13_score.blank? or h14_score.blank? or h15_score.blank? or h16_score.blank? or h17_score.blank? or h18_score.blank?
  end

  def any_h1_to_h9_fairway?
    h1_fairway? or h2_fairway? or h3_fairway? or h4_fairway? or h5_fairway? or h6_fairway? or h7_fairway? or h8_fairway? or h9_fairway?
  end
  def any_h10_to_h18_fairway?
    h10_fairway? or h11_fairway? or h12_fairway? or h13_fairway? or h14_fairway? or h15_fairway? or h16_fairway? or h17_fairway? or h18_fairway?
  end

  def any_h1_to_h9_gir?
    h1_gir? or h2_gir? or h3_gir? or h4_gir? or h5_gir? or h6_gir? or h7_gir? or h8_gir? or h9_gir?
  end
  def any_h10_to_h18_gir?
    h10_gir? or h11_gir? or h12_gir? or h13_gir? or h14_gir? or h15_gir? or h16_gir? or h17_gir? or h18_gir?
  end

那么如何从模型中访问params呢？

Answer 1

不要让参数偷偷靠近模型。在这种情况下没有 Controller 的意义。相反，从 Railscasts 查看这一集它讨论了不进入数据库但仍可用于验证的虚拟属性。

虚拟属性不需要相应的模型属性。定义类的局部属性，例如保存状态的 @no_fairways。

class ScoreCard < ActiveRecord::Base
  # define attributes and accessors for both fields
  attr_accessor :no_fairways, :no_girs

  ..
end

现在在你的表单中，你可以写:

<% form_for @scorecard %>
  <%= f.check_box :no_fairways %>
<% end %>