验证特定操作的模型 [英] Validate model for certain action

问题描述

我只需要针对特定​​操作 (:create) 验证模型.我知道这不是一个好策略，但我只需要在我的情况下这样做.

I need to validate a model only for a certain action (:create). I know this is not a good tactic, but i just need to do this in my case.

我尝试使用类似的东西:

I tried using something like :

validate :check_gold, :if => :create

或

validate :check_gold, :on => :create

但是我遇到了错误.问题是我不能在编辑时执行我的自定义 check_gold 验证，而只能在创建时执行(因为必须在创建联盟时执行检查黄金，而不是编辑).

But i get errors. The problem is that i cannot have my custom check_gold validation execute on edit, but only on create (since checking gold has to be done, only when alliance is created, not edited).

感谢阅读:)

我正在附加一些实际代码:

I'm appending some actual code :

  attr_accessor :required_gold, :has_alliance
  validate :check_gold
  validate :check_has_alliance

这是联盟模式.:required_gold 和 :has_alliance 都在控制器中设置(它们是虚拟属性，因为我需要来自控制器的信息).现在，实际的验证器是:

This is the Alliance model. :required_gold and :has_alliance are both set in the controller(they are virtual attributes, because i need info from the controller). Now, the actual validators are:

  def check_gold
    self.errors.add(:you_need, "100 gold to create your alliance!") if required_gold < GOLD_NEEDED_TO_CREATE_ALLIANCE
  end

  def check_has_alliance
    self.errors.add(:you_already, "have an alliance and you cannot create another one !") if has_alliance == true
  end

这非常适合创建，但我想将其限制为单独创建，而不是编辑或脚手架的其他操作.

This works great for create, but i want to restrict it to create alone and not edit or the other actions of the scaffold.

推荐答案

所有 ActiveRecord 验证器都有一个 :on 选项.

All ActiveRecord validators have a :on option.

validates_numericality_of :value, :on => :create 

使用 validate_on_create 回调代替 validate:

validate_on_create :check_gold
validate_on_create :check_has_alliance

如果您使用 validates_each，您可以使用可用于验证器声明的标准选项.

If you use validates_each you can use the standard options available for a validator declaration.

validates_each :required_gold, :has_alliance, :on => :create do |r, attr, value|
  r.check_gold if attr == :required_gold
  r.check_has_alliance if attr == :has_alliance
end

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