ruby-on-rails – 在已毁坏的嵌套模型栏中的validates_uniquenes

发布时间：2020-12-16 20:22:14 所属栏目：百科来源：网络整理

导读：我有一个Project模型可以接受Task的嵌套属性. class Project ActiveRecord::Base has_many :tasks accepts_nested_attributes_for :tasks,:allow_destroy = :trueendclass Task ActiveRecord::Base validates_uniqueness_of :name end 任务模型中的唯一性验

我有一个Project模型可以接受Task的嵌套属性.

class Project < ActiveRecord::Base  
  has_many :tasks

  accepts_nested_attributes_for :tasks,:allow_destroy => :true

end

class Task < ActiveRecord::Base  
validates_uniqueness_of :name end

任务模型中的唯一性验证在更新项目时有问题.

在编辑项目时,我删除一个任务T1,然后添加一个同名T1的新任务,唯一性验证限制了项目的保存.

params哈希看起来像

task_attributes => { {"id" =>
"1","name" => "T1","_destroy" =>
"1"},{"name" => "T1"}}

任务验证在销毁旧任务之前完成.因此验证失败.任何想法如何验证,以至于不考虑任务被销毁？

解决方法

安德鲁·法国在这个 thread年创建了一个补丁,其中的验证是在内存中完成的.

class Author
  has_many :books

  # Could easily be made a validation-style class method of course
  validate :validate_unique_books

  def validate_unique_books
    validate_uniqueness_of_in_memory(
      books,[:title,:isbn],'Duplicate book.')
  end
end

module ActiveRecord
  class Base
    # Validate that the the objects in +collection+ are unique
    # when compared against all their non-blank +attrs+. If not
    # add +message+ to the base errors.
    def validate_uniqueness_of_in_memory(collection,attrs,message)
      hashes = collection.inject({}) do |hash,record|
        key = attrs.map {|a| record.send(a).to_s }.join
        if key.blank? || record.marked_for_destruction?
          key = record.object_id
        end
        hash[key] = record unless hash[key]
        hash
      end
      if collection.length > hashes.length
        self.errors.add_to_base(message)
      end
    end
  end
end

（编辑：李大同）

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