Question

我想为模型添加条件自定义验证

Rails允许创建方法以创建自定义验证

class Invoice < ApplicationRecord
  validate :expiration_date_cannot_be_in_the_past

  def expiration_date_cannot_be_in_the_past
    if expiration_date.present? && expiration_date < Date.today
      errors.add(:expiration_date, "can't be in the past")
  end
end

它还允许创建条件验证

class Order < ApplicationRecord
  validates :card_number, presence: true, if: :paid_with_card?

  def paid_with_card?
    payment_type == "card"
  end
end

我如何混合使用？

我的猜测就像是

validate :condition, if: :other_condition

但这会创建一个SyntaxError：

syntax error, unexpected end-of-input, expecting keyword_end

Answer 1

当您在end中将缺失的结束if修复为已打开的expiration_date_cannot_be_in_the_past时，您可以执行以下操作：

validate :expiration_date_cannot_be_in_the_past, if: :paid_with_card?

Answer 2

您可以使用每个验证器。为此，您必须按照以下步骤操作：

在validators目录中创建名为app的文件夹。
创建名为some_validator.rb

编写代码如下：

class SomeValidator < ActiveModel::EachValidator
 def validate_each(object, attribute, value)
   return unless value.present?
   if some_condition1
     object.errors[attribute] << 'error msg for condition1'
   end
  object.errors[attribute] << 'error msg 2' if condition2
  object.errors[attribute] << 'error msg 3' if condition3
  object.errors[attribute] << 'error msg 4' if condition4
end

端

现在由此自定义验证程序验证，如： validates :attribute_name, some: true
确保您在验证器上使用相同的名称。您可以在此自定义验证程序中编写多个条件。

Answer 3

你错过了结束，纠正了代码：

class Invoice < ApplicationRecord
  validate :expiration_date_cannot_be_in_the_past

  def expiration_date_cannot_be_in_the_past
    if expiration_date.present? && expiration_date < Date.today
      errors.add(:expiration_date, "can't be in the past")
    end # this end you missed in code
  end
end

Answer 4

class User < ApplicationRecord

  validate :email_not_changeable, on: :update

  private

  def email_not_changeable
    if self.email_changed? && self.persisted?
      errors.add(:email, "can't be changed")
    end
  end
end

Rails 5：添加条件自定义验证

4 个答案: