基于 ActiveRecord 验证错误的决策

发布于 2024-12-14 20:07:56 字数 932 浏览 0 评论 0原文

我对 Rails 很陌生，想知道最好的方法是什么：

我有一个控制器在数据库中创建一条记录。

如果发生特定的验证错误，我想设置一个标志，但我看不到使用我熟悉的 Rails 模式来完成此操作的好方法。

我想要检测的模型验证是：

validates_uniqueness_of :title

我的控制器正在执行以下操作：

fcs = Entity.create(:title => text)

当上述错误失败时，我有一个 ActiveModel 错误集合可以使用。

我应该如何可靠地设置一个标志来以编程方式指示标题已被占用？

到目前为止，我已经考虑过，

fcs.errors.messages.has_key?(:title)

但如果标题因其他原因失败，这将返回 true。所以我需要更多类似的东西：

fcs.errors.messages[:title]==["has already been taken"]

但这将是一个令人头痛的维护问题，而且也会被不同的区域设置所破坏......

所以有人知道这应该如何用 RoR 来完成吗？

感谢您的任何建议

编辑：建议标志“is_title_duplicate”的示例用法：

if(! fcs.errors.empty?)
      json['success']=false
      json['errors']=fcs.errors.full_messages
      json['title_was_duplicate'] = is_title_duplicated
      render :json => json

...

原文

I'm very new to rails and am wondering what the best way to do this is:

I have a controller creating a record in the database.

If a specific validation error occurs I want to set a flag, and I can't see a good way to accomplish this with the rails patterns I am familiar with.

The models validation that I want to detect is:

validates_uniqueness_of :title

My controller is doing this:

fcs = Entity.create(:title => text)

When the above error fails I have an ActiveModel errors collection to work with.

How should I go about reliably setting a flag to indicate programatically that the title has been taken?

So far I've considered

fcs.errors.messages.has_key?(:title)

But this will return true if title has failed for some other reason. So I would need something more like:

fcs.errors.messages[:title]==["has already been taken"]

But that would be a maintenance headache and would also be broken by different locales...

So does anyone know how this should be done with RoR?

Thanks for any advice

edit: Example usage of proposed flag "is_title_duplicated":

if(! fcs.errors.empty?)
      json['success']=false
      json['errors']=fcs.errors.full_messages
      json['title_was_duplicate'] = is_title_duplicated
      render :json => json

...

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美煞众生 2024-12-21 20:07:56

我建议向您的模型类添加一个方法来检测唯一性。

class Entity < ActiveRecord::Base
  def unique_title?
    Entity.where(:title => title).count > 0
  end
end

当然，这意味着您要运行该查询两次（一次针对 validates_uniqueness_of，一次针对 unique_title?）。只要性能可以接受，我更喜欢可读性而不是性能。如果性能不可接受，您仍然有选择。您可以在自己的自定义验证中重复使用 unique_title? 并缓存结果。

class Entity < ActiveRecord::Base
  validate :title_must_be_unique

  def unique_title?
    # you may want to unset @unique_title when title changes
    if @unique_title.nil?
      @unique_title = Entity.where(:title => title).count > 0
    end
    @unique_title
  end

  private

  def title_must_be_unique
    unless unique_title?
      errors.add(:title, I18n.t("whatever-the-key-is-for-uniqueness-errors"))
    end
  end
end

I recommend adding a method to your model class to detect uniqueness.

class Entity < ActiveRecord::Base
  def unique_title?
    Entity.where(:title => title).count > 0
  end
end

Of course, this would mean that you're running that query twice (once for the validates_uniqueness_of and once for unique_title?). I prefer readability over performance as long as the performance is acceptable. If the performance is not acceptable, you still have options. You can re-use unique_title? in your own custom validation and cache the result.

class Entity < ActiveRecord::Base
  validate :title_must_be_unique

  def unique_title?
    # you may want to unset @unique_title when title changes
    if @unique_title.nil?
      @unique_title = Entity.where(:title => title).count > 0
    end
    @unique_title
  end

  private

  def title_must_be_unique
    unless unique_title?
      errors.add(:title, I18n.t("whatever-the-key-is-for-uniqueness-errors"))
    end
  end
end

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