Rails - 模型中的UndefinedMethod＃new action

Question

我的routes.rb看起来像这样：

resources :users do
 resources :reservations do
  resources :orders
 end
end

resources :reservations do
 resources :orders 
end 

型号：

class User < ActiveRecord::Base
  has_many :reservations
  has_many :orders, :through => :reservations
end

class Reservation < ActiveRecord::Base
  has_one :order
  belongs_to :user
end

class Order < ActiveRecord::Base
  belongs_to :reservation
end

控制器：

class ReservationsController < ApplicationController

  def new
   if current_user
    @user         = User.find_by_id(current_user)
    @reservation  = @user.reservations.build
   else
    @reservation  = Reservation.new
   end
  end

  #leaving out the save portion to make question shorter. 
  def create
   if current_user
    @user         = User.find(current_user)
    @reservation  = @user.reservations.create(reservation_params)
   else
    @reservation  = Reservation.new(reservation_params)
   end
  end 
end

class OrdersController < ApplicationController

  def new
   if current_user
    @user         = User.find_by_id(current_user)
    @order        = @user.build_order
   else
    @reservation  = Reservation.find_by_id(params[:reservation_id])
    @order        = @reservation.build_order
   end
  end

  def create
   if current_user
    @user         = User.where(current_user)
    @order        = @user.orders.create(order_params)
   else
    @reservation  = Reservation.find(params[:reservation_id])
    @order        = @reservation.create_order(order_params)
   end
  end
end

错误

OrdersController中的NoMethodError #new

＃

的未定义方法`build_order'

完整堆栈跟踪是这样的：

activemodel (4.2.5) lib/active_model/attribute_methods.rb:433:in                     `method_missing'
app/controllers/orders_controller.rb:29:in `new'
actionpack (4.2.5)     lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.2.5) lib/abstract_controller/base.rb:198:in `    process_action'
actionpack (4.2.5) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.5) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.5) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.5) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.5) lib/active_support/callbacks.rb:555:in `block (2 levels) in compile'
activesupport (4.2.5) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.5) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.5) lib/active_support/callbacks.rb:92:in     `__run_callbacks__'
activesupport (4.2.5) lib/active_support/callbacks.rb:778:in     `_run_process_action_callbacks'
activesupport (4.2.5) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.5) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.5) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.5)     lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (4.2.5) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.5) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.5) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.5) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.5) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.5) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.5) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.5) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.5) lib/action_controller/metal.rb:196:in `dispatch'
actionpack (4.2.5) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.5) lib/action_controller/metal.rb:237:in `block in action'
actionpack (4.2.5) lib/action_dispatch/routing/route_set.rb:76:in `call'
actionpack (4.2.5) lib/action_dispatch/routing/route_set.rb:76:in `dispatch'
actionpack (4.2.5) lib/action_dispatch/routing/route_set.rb:45:in `serve'
actionpack (4.2.5) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.5) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.5) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.5) lib/action_dispatch/routing/route_set.rb:817: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 (4.2.5) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.5) 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 (4.2.5) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.5) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.5) lib/active_record/connection_adapters/abstract/connection_pool.rb:653:in `call'
activerecord (4.2.5) lib/active_record/migration.rb:377:in `call'
actionpack (4.2.5) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.5) lib/active_support/callbacks.rb:88:in     `__run_callbacks__'
activesupport (4.2.5) lib/active_support/callbacks.rb:778:in     `_run_call_callbacks'
activesupport (4.2.5) lib/active_support/callbacks.rb:81:in     `run_callbacks'
actionpack (4.2.5) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.5) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.5) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.5)             lib/action_dispatch/middleware/debug_exceptions.rb:17: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 `catch'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `call'
actionpack (4.2.5)     lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.5) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.5) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.5) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.5) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.5) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.5) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.5) 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 (4.2.5)     lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.5) lib/action_dispatch/middleware/static.rb:116:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
railties (4.2.5) lib/rails/engine.rb:518:in `call'
railties (4.2.5) lib/rails/application.rb:165:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
puma (3.1.0) lib/puma/configuration.rb:227:in `call'
puma (3.1.0) lib/puma/server.rb:561:in `handle_request'
puma (3.1.0) lib/puma/server.rb:406:in `process_client'
puma (3.1.0) lib/puma/server.rb:271:in `block in run'
puma (3.1.0) lib/puma/thread_pool.rb:111:in `call'
puma (3.1.0) lib/puma/thread_pool.rb:111:in `block in spawn_thread'

我可以在没有'current_user'的情况下进行预订和订购但我遇到的问题是当用户登录时我可以预订并保存到DB然后我在订单#new controller @order = @ user.build_order行中得到no方法错误。我尝试过很多变种，例如@ user.order.new，@ user.order.build

我也尝试过@order = @ user.reservations.order（params [：reservation_id]），但这会导致我发出订单_form的'to_key'问题。

我提到的所有选项都没有，也没有我尝试过的更多我不记得了的选项。我非常感谢帮助。

如果我需要更多信息，请告诉我，我会尽快发布。

Answer 1

将@user.build_order更改为@user.orders.build。

前者用于指向拥有对象的belongs_to关联。

后者用于has_many - 样式关联，指向集合，即。 “建立在这个用户的订单上。”

您的用户拥有一系列订单（has_many关联），因此您可以在用户的​​订单集合上调用build，而不是用户自己。

Answer 2

您的User has_many :orders。 @user.build_order只有在has_one :order中有belongs_to :order或User时才有效。

作为User has_many :orders，您应该在@user.orders.build中使用OrdersController#new。

有关如何建立关系的更多信息，请参阅ActiveRecord::Associations。