ruby-on-rails - 使用 before_save 回调或自定义验证器添加验证错误？

Question

我有一个模型 Listing belongs_to :user。或者，User has_many :listings。每个列表都有一个对其进行分类的类别字段(狗、猫 等)。 User 还有一个名为 is_premium 的 bool 字段。

这是我验证类别的方式...

validates_format_of :category,
                    :with => /(dogs|cats|birds|tigers|lions|rhinos)/,
                    :message => 'is incorrect'

假设我只想让高级用户能够添加老虎、狮子和犀牛。我该怎么做？最好在 before_save 方法中执行此操作吗？

before_save :premium_check

def premium_check
  # Some type of logic here to see if category is tiger, lion, or rhino.
  # If it is, then check if the user is premium. If it's not, it doesn't matter.
  # If user isn't premium then add an error message.
end

提前致谢!

Answer 1

class Listing < ActiveRecord::Base    
  validate :premium_category

  private

  def premium_category
    if !user.is_premium && %w(tigers lions rhinos).include?(category))
      errors.add(:category, "not valid for non premium users")
    end
  end
end