如何限制对资源的索引操作的访问，而不是对属于该用户的单个记录的访问？

Question

这就是我的 ability.rb 的截断版本：

class Ability
  include CanCan::Ability

  def initialize(user)
    alias_action :create, :read, :update, :destroy, to: :crud

    user ||= User.new # guest user (not logged in)
    if user.has_role?(:admin)
      can :manage, :all
    else
      cannot :read, User
      can :crud, User, id: user.id

      # cannot :read, :users unless user.has_role? :admin
    end
  end
end

我的 UsersController 看起来像这样：

class UsersController < ApplicationController
  load_and_authorize_resource
  before_action :set_user, only: [:show, :edit, :update, :destroy]
  before_action :authenticate_user!, except: [:show]
  # truncated for brevity
end

所以在这里，我想做的是 User#Index，我想将其限制为管理员用户。但与此同时，每个用户应该能够访问自己的用户页面。

当我尝试上面的方法时，这对我来说很有意义，我可以访问 /settings 作为 current_user，但我仍然可以访问 Users#Index 这是我不想。

这是日志的样子：

Started GET "/users/1547" for 127.0.0.1 at 2016-06-26 03:39:57 -0500
DEPRECATION WARNING: before_filter is deprecated and will be removed in Rails 5.1. Use before_action instead. (called from <class:UsersController> at myapp/controllers/users_controller.rb:2)
Processing by UsersController#show as HTML
  Parameters: {"id"=>"1547"}
  User Load (2.3ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  LIMIT   [["id", 1547], ["LIMIT", 1]]
  User Load (1.3ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  ORDER BY "users"."id" ASC LIMIT   [["id", 1547], ["LIMIT", 1]]
  Role Load (1.8ms)  SELECT "roles".* FROM "roles" INNER JOIN "users_roles" ON "roles"."id" = "users_roles"."role_id" WHERE "users_roles"."user_id" =  AND (((roles.name = 'admin') AND (roles.resource_type IS NULL) AND (roles.resource_id IS NULL)))  [["user_id", 1547]]
  CACHE (0.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  LIMIT   [["id", 1547], ["LIMIT", 1]]
  Rendering users/show.html.erb within layouts/application
  Rendered shared/_navbar.html.erb (2.4ms)
  Rendered shared/_footer.html.erb (1.3ms)
Completed 200 OK in 244ms (Views: 196.4ms | ActiveRecord: 16.7ms)


Started GET "/settings" for 127.0.0.1 at 2016-06-26 03:39:59 -0500
Processing by Devise::RegistrationsController#edit as HTML
  User Load (1.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  ORDER BY "users"."id" ASC LIMIT   [["id", 1547], ["LIMIT", 1]]
  Rendering devise/registrations/edit.html.erb within layouts/application
  Rendered devise/registrations/edit.html.erb within layouts/application (16.7ms)
  Rendered shared/_navbar.html.erb (2.8ms)
  Rendered shared/_footer.html.erb (1.0ms)
Completed 200 OK in 184ms (Views: 180.4ms | ActiveRecord: 1.2ms)


Started GET "/users" for 127.0.0.1 at 2016-06-26 03:40:01 -0500
Processing by UsersController#index as HTML
  User Load (2.4ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  ORDER BY "users"."id" ASC LIMIT   [["id", 1547], ["LIMIT", 1]]
  Role Load (2.2ms)  SELECT "roles".* FROM "roles" INNER JOIN "users_roles" ON "roles"."id" = "users_roles"."role_id" WHERE "users_roles"."user_id" =  AND (((roles.name = 'admin') AND (roles.resource_type IS NULL) AND (roles.resource_id IS NULL)))  [["user_id", 1547]]
  Rendering users/index.html.erb within layouts/application
  User Load (1.3ms)  SELECT "users".* FROM "users"
  Rendered users/index.html.erb within layouts/application (7.2ms)
Started GET "/users" for 127.0.0.1 at 2016-06-26 03:40:02 -0500
Processing by UsersController#index as HTML
  User Load (2.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  ORDER BY "users"."id" ASC LIMIT   [["id", 1547], ["LIMIT", 1]]
  Role Load (3.8ms)  SELECT "roles".* FROM "roles" INNER JOIN "users_roles" ON "roles"."id" = "users_roles"."role_id" WHERE "users_roles"."user_id" =  AND (((roles.name = 'admin') AND (roles.resource_type IS NULL) AND (roles.resource_id IS NULL)))  [["user_id", 1547]]
  Rendering users/index.html.erb within layouts/application
  User Load (51.5ms)  SELECT "users".* FROM "users"
  Rendered users/index.html.erb within layouts/application (55.1ms)
  Rendered shared/_navbar.html.erb (3.4ms)
  Rendered shared/_footer.html.erb (1.3ms)
Completed 200 OK in 533ms (Views: 488.8ms | ActiveRecord: 5.8ms)

但是当我注释掉这一行时：can :crud, User, id: user.id，所以我只有 cannot :read, User 行，它使我无法访问所有内容，如下面的日志所示（这也是我不知道的）我不想）。

Started GET "/users" for 127.0.0.1 at 2016-06-26 03:45:39 -0500
Processing by UsersController#index as HTML
  User Load (1.1ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  ORDER BY "users"."id" ASC LIMIT   [["id", 1547], ["LIMIT", 1]]
  Role Load (1.3ms)  SELECT "roles".* FROM "roles" INNER JOIN "users_roles" ON "roles"."id" = "users_roles"."role_id" WHERE "users_roles"."user_id" =  AND (((roles.name = 'admin') AND (roles.resource_type IS NULL) AND (roles.resource_id IS NULL)))  [["user_id", 1547]]
Redirected to http://localhost:3000/
Completed 302 Found in 19ms (ActiveRecord: 2.4ms)


Started GET "/users" for 127.0.0.1 at 2016-06-26 03:45:39 -0500
Processing by UsersController#index as HTML
  User Load (1.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" =  ORDER BY "users"."id" ASC LIMIT   [["id", 1547], ["LIMIT", 1]]
  Role Load (2.8ms)  SELECT "roles".* FROM "roles" INNER JOIN "users_roles" ON "roles"."id" = "users_roles"."role_id" WHERE "users_roles"."user_id" =  AND (((roles.name = 'admin') AND (roles.resource_type IS NULL) AND (roles.resource_id IS NULL)))  [["user_id", 1547]]
Redirected to http://localhost:3000/
Completed 302 Found in 24ms (ActiveRecord: 4.0ms)

那么我该如何实现我想要做的事情呢？

Answer 1

不确定，但是怎么样：

def initialize(user)
  alias_action :create, :read, :update, :destroy, to: :crud

  user ||= User.new # guest user (not logged in)
  if user.has_role?(:admin)
    can :manage, :all
  else
    cannot :read, User
    can :crud, User, id: user.id
    cannot :index, User
  # cannot :read, :users unless user.has_role? :admin
  end
end

如何限制对资源的索引操作的访问，而不是对属于该用户的单个记录的访问？

How do I restrict access to the index action of my resource, but not to the individual record that belongs to that user?

ruby-on-rails

ruby-on-rails-5

cancancan

rolify