通过CanCanCan规则中的自引用关联进行过滤

• Z时代
• 2024-01-10
• 分类：问答

在我的项目中，我有一个Post类，它可以是其他帖子的评论，其中self-join。除了其他的规则，我想启用它属于“发布”后的评论通过CanCanCan规则中的自引用关联进行过滤

我用下面的宝石帖子：

gem 'rails', '5.0.6' 
gem 'cancancan', '2.1.2' 

下面是模型和能力类

class Post < ActiveRecord::Base 
    belongs_to :user 
    belongs_to :parent, class_name: 'Post', optional: true 
    has_many :comments, class_name: 'Post', foreign_key: 'parent_id', dependent: :destroy 
end 
class User < ActiveRecord::Base 
    has_many :posts 
end 
class Ability 
    include CanCan::Ability 
    def initialize(user) 
    can :read, Post, parent: { status: %w(published), user: { id: user.id } } 
    end 
end 

我写了一些RSpec测试，他们都应该根据上面的规则通过。

RSpec.describe Ability do 
    subject(:ability){ Ability.new(user) } 
    let!(:user) { User.create } 
    let!(:commenter) { User.create } 
    let!(:post) { Post.create(user: user, parent: nil, status: 'published') } 
    let!(:comment) { Post.create(user: commenter, parent: post) } 
    # for individual objects it works 
    it { is_expected.not_to be_able_to :read, post } # pass 
    it { is_expected.to be_able_to :read, comment } # pass 
    # for accessible by query it fails 
    it { expect(Post.accessible_by(ability)).not_to include post } # pass 
    it { expect(Post.accessible_by(ability)).to include comment } # fail 
end 

当我运行RSpec测试时，最后一个失败。如果您检查SQL日志，您可以看到它创建了正确的JOINS，但它有一个错误的WHERE语句。

SELECT (...) 
FROM "posts" 
LEFT OUTER JOIN "posts" "parents_posts" ON "parents_posts"."id" = "posts"."parent_id" 
LEFT OUTER JOIN "users" ON "users"."id" = "parents_posts"."user_id" 
WHERE "posts"."status" = 'published' 
AND "users"."id" = ? 

你能帮我吗？这是CanCanCan中的错误还是我错误地使用了hash syntax？

回答：

def initialize(user) 
    can :read, Post, id: Post.where(parent: { status: 'published', user: { id: user.id }) } 
end 

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