我使用deviseand cancangems 并且有简单的模型关联：user has_many subscriptions, subscription belongs_to :user. 有以下SubscriptionsController：
class SubscriptionsController < ApplicationController
load_and_authorize_resource :user
load_and_authorize_resource :subscription, through: :user
before_filter :authenticate_user!
def index
@subscriptions = @user.subscriptions.paginate(:page => params[:page]).order(:created_at)
end
#other actions
end
并且Cancan Ability.rb：
class Ability
include CanCan::Ability
def initialize(user)
user ||=User.new
can [:read], [Edition, Kind]
if user.admin?
can :manage, :all
elsif user.id
can [:read, :create, :destroy, :pay], Subscription, user_id: user.id
can [:delete_from_cart, :add_to_cart, :cart], User, id: user.id
end
end
end
问题是我不能subscriptions以用户身份使用操作，但可以以管理员身份使用。并且没有问题UsersController。当我从以下行中删除SubscriptionsController：
load_and_authorize_resource :user
load_and_authorize_resource :subscription, through: :user
before_filter :authenticate_user!
完全没有问题。所以问题在这些行或Ability.rb. 有什么建议么？
更新：有趣的是，如果我将 smth like 添加can? :index, Subscription到 html 模板中，它会显示true. 如果添加 smth like can? :index, Subscription.first（另一个用户的订阅），它会显示false. 看起来Cancan工作正常。但是有什么问题吗？...
更新：如果更改SubscriptionsControlle如下：
class SubscriptionsController < ApplicationController
#load_and_authorize_resource :user
#load_and_authorize_resource :subscription, through: :user
before_filter :authenticate_user!
def show
@user = User.find params[:user_id] #line 1
@subscription = @user.subscriptions.find params[:id] #line 2
@container_items = @subscription.container_items.paginate(:page => params[:page])
authorize! :show, @subscription #line 4
end
#some actions
end
它可以完美运行，并在需要时防止未经授权的用户访问。第 1 行、第 2 行和第 4 行是否不等于已注释？
更新：有以下内容routes.rb：
resources :users, except: [:show] do
member do
get 'cart'
delete 'delete_from_cart' => 'users#delete_from_cart'
post 'add_to_cart' => 'users#add_to_cart'
end
resources :subscriptions do
member do
post 'pay'
end
end
end
更新：下一个解决方案防止未经授权访问所有订阅操作，除了index：
class SubscriptionsController < ApplicationController
load_resource :user
load_resource :subscription, through: :user
authorize_resource through: :current_user
before_filter :authenticate_user!
#actions
end
那么阻止访问index操作的最佳方法是什么？
仅找到以下解决方案：
before_filter :authorize_index, only: [:index]
def authorize_index
raise CanCan::AccessDenied unless params[:user_id] == current_user.id.to_s
end