验证多态关联模型中的范围唯一性

Question

是的,所以我有一个多态关联,允许不同的对象类型被收藏.所以一个人可以喜欢一个产品,一个人,或其他什么.我想要做的是防止有人使用收藏夹模型中的验证唯一性来复制收藏夹.

class Favorite < ActiveRecord::Base
 belongs_to :favoritable, :polymorphic => true
 belongs_to :user

 attr_accessible :user

 validates_presence_of :user
 validates :user_id, :uniqueness => { :scope => [:favoritable_type, :favoritable_id] }
end

验证似乎正在起作用,但无论出于何种原因,当尝试复制条目时,仍然使用user_id创建新的Favorite行.

有没有办法阻止这个初始保存？

似乎Rails正在创建数据库条目,然后使用favoritable_id和favoritable_type更新它,如下所示:

  SQL (28.3ms)  INSERT INTO "favorites" ("created_at", "favoritable_id", "favoritable_type", "updated_at", "user_id") VALUES ($1, $2, $3, $4, $5) RETURNING "id"  [["created_at", Tue, 14 Aug 2012 10:26:31 UTC +00:00], ["favoritable_id", nil], ["favoritable_type", nil], ["updated_at", Tue, 14 Aug 2012 10:26:31 UTC +00:00], ["user_id", 23]]
   (7.8ms)  COMMIT
   (0.1ms)  BEGIN
  Favorite Exists (0.3ms)  SELECT 1 AS one FROM "favorites" WHERE ("favorites"."user_id" = 23 AND "favorites"."id" != 123 AND "favorites"."favoritable_type" = 'Style' AND "favorites"."favoritable_id" = 29) LIMIT 1
   (0.2ms)  UPDATE "favorites" SET "favoritable_id" = 29, "favoritable_type" = 'Style', "updated_at" = '2012-08-14 10:26:31.943937' WHERE "favorites"."id" = 123
   (6.7ms)  COMMIT
   (0.1ms)  BEGIN

Answer 1

如果你仔细观察你可以发现唯一性验证工作正常:)

validates :user_id, :uniqueness => { :scope => [:favoritable_type, :favoritable_id] }

查看您添加的数据图像.你可以发现内部图像没有第二个记录,favouritable而第一个记录是不同的,因此2个记录是uniq并且它没有问题uniqueness但是它的逻辑差距.

如果您严格要避免第二次进入,请​​保留favouritable为必填字段

validates :favoritable_type, :favoritable_id, :presence => true

Answer 2

class Favorite < ActiveRecord::Base

  belongs_to :user
  belongs_to :favoritable, polymorphic: true

  validates :user_id, :favoritable_id, presence: true,
    numericality: { only_integer: true }

  validates :favoritable_type, presence: true,
    inclusion: { 
      in: %w(FirstModelName SecondModelName),
      message: "%{value} is not a valid" 
    }

  validates :user_id, uniqueness: { scope: [ :favoritable_type, :favoritable_id ] }
end