Rails - 模型#new 动作中的未定义方法

Question

我的 routes.rb 看起来是这样的：

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 中没有方法错误#new

#

的未定义方法“build_order”

完整的堆栈跟踪是这样的：

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，但我运行遇到的问题是当用户登录时我可以进行预订并将其保存到数据库，但随后我在 Orders#new controller @order = @user.build_order 行中收到无方法错误。我尝试了很多变体，例如@user.order.new、@user.order.build

我也试过 @order = @user.reservations.order(params[:reservation_id]) 但这导致我遇到订单 _form 的 'to_key' 问题。

我提到的

None 个选项都行得通，也没有我尝试过的更多选项我不记得了。我将不胜感激帮助。

如果需要我提供更多信息，请告诉我，我会尽快post。

Answer 1

你的 User has_many :orders。 @user.build_order 仅当您的 User 中有 has_one :order 或 belongs_to :order 时才有效。

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

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

Answer 2

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

前者用于 belongs_to 指向拥有对象的关联。

后者用于指向集合的 has_many 样式关联，即。 "build onto this user's orders."

您的用户有一个订单集合（has_many 关联），因此您对用户的订单集合而不是用户本身调用 build。

Rails - 模型#new 动作中的未定义方法

Rails - UndefinedMethod in model#new action

ruby-on-rails

rails-routing

ruby-on-rails-4