ruby-on-rails - ArticlesController 中的 NoMethodError#create

Question

所以我正在尝试按照此处的教程进行操作:http://guides.rubyonrails.org/getting_started.html

我对正在发生的事情有一些想法，但在这一点上，我变得越来越沮丧，并且没有准备好以一种有意义的方式来看待这个问题。这是我目前的 Controller 。这很简单，我想我知道发生了什么:

articles_controller.rb
class ArticlesController < ApplicationController
def new
end

def create
  @article = Article.new(article_params)

  @article.save
  redirect_to @article
end

private
  def article_params
    params.require(:article).permit(:title, :text)
  end
end

路线.rb

Rails.application.routes.draw do
  get 'welcome/index'
Rails.application.routes.draw do
    resource :articles
root 'welcome#index'
    end
end

但我现在力不从心，无法继续。如果它有所作为，我正在运行 Windows 8 专业版。任何帮助，将不胜感激。我可以看出错误与“redirect_to”有关，但除此之外我什么都不知道!我的错误现在看起来像:

NoMethodError in ArticlesController#create
undefined method `article_url' for #<ArticlesController:0x979bfc0>
Extracted source (around line #0):

app/controllers/articles_controller.rb:9:in `create'

堆栈跟踪看起来像这样:

actionpack (4.2.0) lib/action_dispatch/routing/polymorphic_routes.rb:268:in `handle_model_call'
actionpack (4.2.0) lib/action_dispatch/routing/url_for.rb:167:in `url_for'
actionpack (4.2.0) lib/action_controller/metal/redirecting.rb:95:in `_compute_redirect_to_location'
turbolinks (2.5.3) lib/turbolinks/xhr_headers.rb:21:in `_compute_redirect_to_location'
actionpack (4.2.0) lib/action_controller/metal/redirecting.rb:75:in `redirect_to'
actionpack (4.2.0) lib/action_controller/metal/flash.rb:57:in `redirect_to'
actionpack (4.2.0) lib/action_controller/metal/instrumentation.rb:61:in `block in redirect_to'
activesupport (4.2.0) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.0) lib/action_controller/metal/instrumentation.rb:60:in `redirect_to'
app/controllers/articles_controller.rb:9:in `create'
actionpack (4.2.0) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.2.0) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.0) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.0) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:234:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:234:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:92:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:92:in `_run_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:734:in `_run_process_action_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.2.0) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.0) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.0) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.0) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.0) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.0) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.2.0) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.0) lib/action_controller/metal.rb:236:in `block in action'
actionpack (4.2.0) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (4.2.0) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (4.2.0) lib/action_dispatch/routing/route_set.rb:42:in `serve'
actionpack (4.2.0) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.0) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.0) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.0) lib/action_dispatch/routing/route_set.rb:802:in `call'
rack (1.6.0) lib/rack/etag.rb:24:in `call'
rack (1.6.0) lib/rack/conditionalget.rb:38:in `call'
rack (1.6.0) lib/rack/head.rb:13:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.0) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.0) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.0) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:647:in `call'
activerecord (4.2.0) lib/active_record/migration.rb:378:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.0) lib/active_support/callbacks.rb:88:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:88:in `_run_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:734:in `_run_call_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
web-console (2.0.0) lib/action_dispatch/debug_exceptions.rb:18:in `middleware_call'
web-console (2.0.0) lib/action_dispatch/debug_exceptions.rb:13:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.0) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.0) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.0) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.0) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.0) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.0) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.0) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.0) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.0) lib/rack/lock.rb:17:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/static.rb:113:in `call'

Answer 1

基本上，“undefined method `article_url' for ”意味着 rails 无法为 @article 记录找到合适的路径。定义路由时，rails 会生成两个以 _url 和 _path 结尾的方法。您可以在您的应用程序中使用它们来访问相应的 url，而无需对它们进行硬编码。查看您的 routes.rb 文件中的代码，我发现了三件事:

1. 您只需要调用一次 Rails.application.routes.draw
2. 为模型生成 CRUD 路由的关键字是“resources”(复数)，而不是“resource”(单数)
3. (与错误无关)您的“get 'welcome/index'”看起来还没有完成。也许你的意思是“get '/index', to: 'welcome#index'”。第一个字符串指定 url 路径，to 指定 controller#action。

尝试使用以下 routes.rb:

Rails.application.routes.draw do
  resources :articles
  root 'welcome#index'
end

我建议您也查看 routing guide当你在做的时候。祝你好运!