英文:
Checking if attribute_changed? in ActiveModel::EachValidator
问题
我有一个名为Person的类，它有first_name、middle_name和last_name这三个属性。
我有一个自定义的Each验证器，用于这三个属性，如下所示：
validates :first_name, :middle_name, :last_name, nameValidator: true
在这个验证器中，我想要检查这3个属性中是否有任何一个发生了变化，并在满足一些其他条件的情况下验证名称。为此，我正在尝试使用attribute_changed?，但它不起作用。
我已经查看了ActiveModel::Dirty和Activerecod::Dirty的不同方法，但似乎没有任何方法可以检查每个属性的变化。我漏掉了什么？
module Person
class nameValidator < ActiveModel::EachValidator
def validate_each(record, attribute, value)
return unless can_normalize?(record)
#规范化代码
end
def can_normalize?(record)
anything_new = record.new_record? || record.attribute_changed?(attribute)
end
end
end
英文:
I have a class Person that has first_name, middle_name, last_name.
I have a customed Each validator for these 3 attributes like so
validates :first_name, :middle_name, :last_name, nameValidator: true
In this validator I want to check if any one of these 3 attributes changed and given a few more conditions I'll validate name. For that I'm trying attribute_changed? but it doesn't work.
I've checked different methods from ActiveModel::Dirty and Activerecod::Dirty but nothing seems to work to check changes in each attribute. What am I missing?
module Person
class nameValidator < ActiveModel::EachValidator
def validate_each(record, attribute, value)
return unless can_normalize?(record)
#Normalization code
end
def can_normalize?(record)
anything_new = record.new_record? || attribute_changed?
end
end
end
答案1
得分: 2
如果你需要检查某个属性是否发生了变化，你需要在记录上调用 attribute_changed? 方法，并传递这个属性，如下所示：
return unless record.new_record? || record.attribute_changed?(attribute)
或者可以使用元编程的方法，如下所示：
return unless record.new_record? || record.public_send("#{attribute}_changed?")
一些注意事项：
在 Ruby 中，通常我们使用 PascalCase 来命名类，使用 snake_case 来命名哈希键。
验证通常用于数据验证，而不是一些规范化工作。它通常用于添加验证错误。
英文:
If you need to check that some attribute was changed, you need to call attribute_changed? method on the record and pass this attribute like this
return unless record.new_record? || record.attribute_changed?(attribute)
Or may be use metaprogramming method like this
return unless record.new_record? || record.public_send("#{attribute}_changed?")
Some notes:
In Ruby we usually use PascalCase for class names and snake_case for hash keys
Validations are used for data validation, not for some normalization. It is usually used to add validation errors
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论