Question

我有一定的要求，根据用户的类型，视图具有不同的内容。假设我有用户控制器的索引操作。然后我可以使用cancan来授权这样的动作

authorize! :index, @users

此外，为了过滤内容，我还有其他授权，例如

if can :view_all,User

进一步授权，如

if can :view_some,User将需要另一个。

这将导致很多条件。而不是这个，我可以使用像

这样的简单条件

If the user is with view_all access show him all 
else if the user is with view_some access show him some
else access denied

Cancan需要一个额外的查询，不是吗？我可能以错误的方式使用cancan。需要一些建议。

以下是我的ability.rb文件的粗略片段

    can :index, User do |user1|
      role.accesses.include?(Access.where(:name => "access1").first) || role.accesses.include?(Access.where(:name => "access2").first)
    end

    can :view_all, User do |user1|
      role.accesses.include?(Access.where(:name => "access1").first) 
    end

    can :view_some, User do |user1|
      role.accesses.include?(Access.where(:name => "access2").first) 
    end

Answer 1

Cancan需要一个额外的查询吗？

组合能力时，cancan将使用单个查询。

如果你看看规格，例如。 spec/cancan/model_adapters/active_record_adapter_spec.rb，你会发现这样的规格：

it "should fetch any articles which are published or secret", focus: true do
  @ability.can :read, Article, :published => true
  @ability.can :read, Article, :secret => true
  article1 = Article.create!(:published => true, :secret => false)
  article2 = Article.create!(:published => true, :secret => true)
  article3 = Article.create!(:published => false, :secret => true)
  article4 = Article.create!(:published => false, :secret => false)
  Article.accessible_by(@ability).should == [article1, article2, article3]
end

如果启用SQL日志记录，您将看到该查询结合了以下条件：

Article Load (0.2ms)  
SELECT "with_model_articles_95131".* 
FROM "with_model_articles_95131" 
WHERE (("with_model_articles_95131"."secret" = 't') 
  OR ("with_model_articles_95131"."published" = 't'))

以正确的方式使用cancan

1 个答案: