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