Rails 4 – Pundit – 如何编写范围
我试图学习如何使用Pundit和Rails 4.我在过去的两年里一直试图学习这一点，并且正在慢慢地取得一些进展。
我也在努力学习如何编写范围。 我还在试图弄清楚如何将建议翻译成简单的英语，以便我可以开始理解。
我陷入了范围专家政策使用和我可以在模型中编写的一般范围类的交叉点。
我有Uer，Profile和Project的模型。
协会是：
用户
has_one :profile 轮廓
belongs_to :user has_many :projects
项目
belongs_to :profile
我正在尝试编写一个权威策略，允许不同的用户查看不同的项目。 我正在写一个范围的政策，专家来管理这个。
在我的项目模型中，我正在尝试编写查找所有用户项目的范围。 用简单的英语，我想搜索所有项目，以查找那些属于用户ID等于当前用户的配置文件ID的项目。
在我的专家政策中，我正在尝试编写此解决方法：
class Scope attr_reader :user, :scope def initialize(user, scope) @user = user @scope = scope end def resolve if user.has_role?(:admin) scope.all elsif user.id == @project.profile.user_id scope.projects_for_user elsif user.present? scope.in_state(:publish) else Project.none end end end
我尝试了大约100种不同的方法来尝试在我的项目模型上编写一个范围，找到属于当前用户的项目。 我知道我不能在模型中使用devise的current_user，所以我不能在范围内使用它。 这两个是我最好的尝试 – 都是错的。
scope :projects_for_user, -> { joins(:user_id).where('project.profile.user_id = ?', user.id) } scope :projects_for_user, -> { where(project.profile.user_id: User.id) }
学习这个的主要问题是我看不出如何将这条线解构成不同的部分。
根据我的理解，“：”之前的位是您正在寻找的东西。 “：”之后的位是您在运行示波器时使用的实例。 如果这是正确的，那么我很困惑为什么我的第二次尝试不起作用（并且在第一次尝试中对连接语句也非常困惑）。
如果有人可以帮助解释如何编写范围的简单英语解释，我相信我知道我想要寻找什么，只是拼命地丢失了如何编写查询来找到它。
目前，当我尝试使用我的项目策略时（我已经尝试将Taryn的建议纳入下面 – 尽管我不了解范围的每个组成部分，所以我不确定它是怎么回事）。
class ProjectPolicy < ApplicationPolicy attr_reader :user, :record class Scope attr_reader :user, :scope def initialize(user, scope) @user = user @scope = scope end def resolve if user.has_role?(:admin) scope.all elsif user.id == @project.profile.user_id scope.projects_for_user(user) elsif user.present? scope.in_state(:publish) else Project.none end end end def index? true end def show? true end private def project record end
项目模型：
scope :projects_for_user, -> (user){ joins(:user_id).where('project.profile.user_id = ?', user.id) }
在我的项目控制器中，我有：
class ProjectsController < ApplicationController before_action :set_project, only: [:show, :edit, :update, :destroy ] before_action :authenticate_user! def index @projects = Project.all authorize @projects end def show @project = Project.find(params[:id]) # authorize @project end private def set_project @project = Project.find(params[:id]) authorize @project end
当我保存并尝试它时，它会出现一个错误：
wrong number of arguments (given 2, expected 0)
当我尝试查看项目或特定项目的索引时，会返回此错误（因此我不认为它与范围有关）。 我不明白为了解决这个问题，我们知道如何解决这两个问题。
添加堆栈跟踪
ArgumentError - wrong number of arguments (given 2, expected 0): pundit (1.1.0) lib/pundit.rb:112:in `policy!' pundit (1.1.0) lib/pundit.rb:235:in `policy' pundit (1.1.0) lib/pundit.rb:194:in `authorize' app/controllers/eois_controller.rb:20:in `show' actionpack (4.2.4) lib/action_controller/metal/implicit_render.rb:4:in `send_action' actionpack (4.2.4) lib/abstract_controller/base.rb:198:in `process_action' actionpack (4.2.4) lib/action_controller/metal/rendering.rb:10:in `process_action' actionpack (4.2.4) lib/abstract_controller/callbacks.rb:20:in `block in process_action' activesupport (4.2.4) lib/active_support/callbacks.rb:117:in `call' activesupport (4.2.4) lib/active_support/callbacks.rb:555:in `block (2 levels) in compile' activesupport (4.2.4) lib/active_support/callbacks.rb:505:in `call' activesupport (4.2.4) lib/active_support/callbacks.rb:92:in `__run_callbacks__' activesupport (4.2.4) lib/active_support/callbacks.rb:778:in `_run_process_action_callbacks' activesupport (4.2.4) lib/active_support/callbacks.rb:81:in `run_callbacks' actionpack (4.2.4) lib/abstract_controller/callbacks.rb:19:in `process_action' actionpack (4.2.4) lib/action_controller/metal/rescue.rb:29:in `process_action' actionpack (4.2.4) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action' activesupport (4.2.4) lib/active_support/notifications.rb:164:in `block in instrument' activesupport (4.2.4) lib/active_support/notifications/instrumenter.rb:20:in `instrument' activesupport (4.2.4) lib/active_support/notifications.rb:164:in `instrument' actionpack (4.2.4) lib/action_controller/metal/instrumentation.rb:30:in `process_action' actionpack (4.2.4) lib/action_controller/metal/params_wrapper.rb:250:in `process_action' searchkick (1.3.0) lib/searchkick/logging.rb:153:in `process_action' activerecord (4.2.4) lib/active_record/railties/controller_runtime.rb:18:in `process_action' actionpack (4.2.4) lib/abstract_controller/base.rb:137:in `process' actionview (4.2.4) lib/action_view/rendering.rb:30:in `process' actionpack (4.2.4) lib/action_controller/metal.rb:196:in `dispatch' actionpack (4.2.4) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch' actionpack (4.2.4) lib/action_controller/metal.rb:237:in `block in action' actionpack (4.2.4) lib/action_dispatch/routing/route_set.rb:76:in `dispatch' actionpack (4.2.4) lib/action_dispatch/routing/route_set.rb:45:in `serve' actionpack (4.2.4) lib/action_dispatch/journey/router.rb:43:in `block in serve' actionpack (4.2.4) lib/action_dispatch/journey/router.rb:30:in `serve' actionpack (4.2.4) lib/action_dispatch/routing/route_set.rb:821:in `call' omniauth (1.3.1) lib/omniauth/strategy.rb:186:in `call!' omniauth (1.3.1) lib/omniauth/strategy.rb:164:in `call' omniauth (1.3.1) lib/omniauth/strategy.rb:186:in `call!' omniauth (1.3.1) lib/omniauth/strategy.rb:164:in `call' omniauth (1.3.1) lib/omniauth/strategy.rb:186:in `call!' omniauth (1.3.1) lib/omniauth/strategy.rb:164:in `call' omniauth (1.3.1) lib/omniauth/strategy.rb:186:in `call!' omniauth (1.3.1) lib/omniauth/strategy.rb:164:in `call' meta_request (0.4.0) lib/meta_request/middlewares/app_request_handler.rb:13:in `call' meta_request (0.4.0) lib/meta_request/middlewares/meta_request_handler.rb:13:in `call' warden (1.2.6) lib/warden/manager.rb:35:in `block in call' warden (1.2.6) lib/warden/manager.rb:34:in `call' rack (1.6.4) lib/rack/etag.rb:24:in `call' rack (1.6.4) lib/rack/conditionalget.rb:25:in `call' rack (1.6.4) lib/rack/head.rb:13:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/params_parser.rb:27:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/flash.rb:260:in `call' rack (1.6.4) lib/rack/session/abstract/id.rb:225:in `context' rack (1.6.4) lib/rack/session/abstract/id.rb:220:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/cookies.rb:560:in `call' activerecord (4.2.4) lib/active_record/query_cache.rb:36:in `call' activerecord (4.2.4) lib/active_record/connection_adapters/abstract/connection_pool.rb:653:in `call' activerecord (4.2.4) lib/active_record/migration.rb:377:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call' activesupport (4.2.4) lib/active_support/callbacks.rb:88:in `__run_callbacks__' activesupport (4.2.4) lib/active_support/callbacks.rb:778:in `_run_call_callbacks' activesupport (4.2.4) lib/active_support/callbacks.rb:81:in `run_callbacks' actionpack (4.2.4) lib/action_dispatch/middleware/callbacks.rb:27:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/reloader.rb:73:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/remote_ip.rb:78:in `call' better_errors (2.1.1) lib/better_errors/middleware.rb:84:in `protected_app_call' better_errors (2.1.1) lib/better_errors/middleware.rb:79:in `better_errors_call' better_errors (2.1.1) lib/better_errors/middleware.rb:57:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call' rack-contrib (1.4.0) lib/rack/contrib/response_headers.rb:17:in `call' meta_request (0.4.0) lib/meta_request/middlewares/headers.rb:16:in `call' web-console (2.3.0) lib/web_console/middleware.rb:28:in `block in call' web-console (2.3.0) lib/web_console/middleware.rb:18:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call' railties (4.2.4) lib/rails/rack/logger.rb:38:in `call_app' railties (4.2.4) lib/rails/rack/logger.rb:20:in `block in call' activesupport (4.2.4) lib/active_support/tagged_logging.rb:68:in `block in tagged' activesupport (4.2.4) lib/active_support/tagged_logging.rb:26:in `tagged' activesupport (4.2.4) lib/active_support/tagged_logging.rb:68:in `tagged' railties (4.2.4) lib/rails/rack/logger.rb:20:in `call' request_store (1.3.1) lib/request_store/middleware.rb:9:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/request_id.rb:21:in `call' rack (1.6.4) lib/rack/methodoverride.rb:22:in `call' rack (1.6.4) lib/rack/runtime.rb:18:in `call' activesupport (4.2.4) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call' rack (1.6.4) lib/rack/lock.rb:17:in `call' actionpack (4.2.4) lib/action_dispatch/middleware/static.rb:116:in `call' rack (1.6.4) lib/rack/sendfile.rb:113:in `call' skylight (0.10.6) lib/skylight/middleware.rb:61:in `call' railties (4.2.4) lib/rails/engine.rb:518:in `call' railties (4.2.4) lib/rails/application.rb:165:in `call' rack (1.6.4) lib/rack/content_length.rb:15:in `call' puma (3.4.0) lib/puma/configuration.rb:224:in `call' puma (3.4.0) lib/puma/server.rb:569:in `handle_request' puma (3.4.0) lib/puma/server.rb:406:in `process_client' puma (3.4.0) lib/puma/server.rb:271:in `block in run' puma (3.4.0) lib/puma/thread_pool.rb:114:in `block in spawn_thread'
在2016-09-08 13:23:01 +1000开始发布“/ __ better_errors / 123578515c1e4e10 / variables”for :: 1
堆积痕迹分析
我自己编写的唯一一行是eois控制器中的授权@eoi行（在show动作中）。 这是使用专家的关键部分。 堆栈跟踪的其余部分来自我没写的东西，不知道如何改变。
app/controllers/eois_controller.rb:20:in `show'
对可能的重复标记的响应
另一个问题也是我发布的问题。 他们会有不同的观点。 在这篇文章中，我想也许我写的范围是错误的（我可能已经）。 在另一篇文章中，我试图阐述整个过程，看看是否有人能够帮助我理解我哪里出错了。
问题是您实际上没有为作用域提供用户ID。 在这一个： User.id这将永远不会工作… User类代表所有用户…询问它的id是没有任何意义的（你只需要取回ruby的id-存储类方法的对象）。
在另一个…你使用user.id但实际上并没有设置user变量的值（所以它总是会失败）。
也许尝试将相关的用户ID作为参数传递给方法，例如：
# define the `user` parameter as an argument to this scope-method scope :projects_for_user, -> (user){ joins(:user_id).where('project.profile.user_id = ?', user.id) } def resolve if user.has_role?(:admin) scope.all elsif user.id == @project.profile.user_id scope.projects_for_user(user) # pass the user into the method elsif user.present? scope.in_state(:publish) else Project.none end end
注意：我没有（也不会）测试这段代码，它可能有拼写错误或错误…给它一个去修复bug。