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我在学习 Michael Hartl 的Rails 教程时遇到了意外错误。一帆风顺。

在完成Hartl 的清单 7.3后，我第一次看到与教程不同的“动作控制器：异常捕获”错误。

具体来说，当尝试访问 /users/1 时，我得到：

用户控制器中的 NoMethodError#show

未定义的方法“键？” 对于零：NilClass

我继续执行清单 7.5——为用户的显示操作添加一个视图，然后将显示操作添加到用户控制器——这解决了 Hartl 遇到的错误，但这些步骤并没有解决我的错误。

基于这个问题，我已经验证了我的 app/models/user.rb 没有拼写错误：在检查了拼写错误之后，我将 Hartl 的代码复制并粘贴到了我的文件中，以防万一。

任何关于在哪里寻找错别字/问题的指导将不胜感激。

编辑 1：根据要求， UsersController#show 方法：

def show
  @user = User.find(params[:id])
end

编辑 2：完整跟踪：

actionpack (3.2.8) lib/action_controller/metal/hide_actions.rb:36:in `visible_action?'

actionpack (3.2.8) lib/action_controller/metal/hide_actions.rb:18:in `method_for_action'

actionpack (3.2.8) lib/action_controller/metal/implicit_render.rb:14:in `method_for_action'

actionpack (3.2.8) lib/action_controller/metal/compatibility.rb:61:in `method_for_action'

actionpack (3.2.8) lib/abstract_controller/base.rb:115:in `process'

actionpack (3.2.8) lib/abstract_controller/rendering.rb:45:in `process'

actionpack (3.2.8) lib/action_controller/metal.rb:203:in `dispatch'

actionpack (3.2.8) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'

actionpack (3.2.8) lib/action_controller/metal.rb:246:in `block in action'

actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `call'

actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'

actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:36:in `call'

旅程 (1.0.4) lib/journey/router.rb:68:in `block in call'

旅程 (1.0.4) lib/journey/router.rb:56:in `each'

旅程 (1.0.4) lib/journey/router.rb:56:in `call'

actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:600:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'

rack (1.4.1) lib/rack/etag.rb:23:in `call'

rack (1.4.1) lib/rack/conditionalget.rb:25:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/head.rb:14:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/params_parser.rb:21:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/flash.rb:242:in `call'

rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context'

rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/cookies.rb:339:in `call'

activerecord (3.2.8) lib/active_record/query_cache.rb:64:in `call'

activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_pool.rb:473:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'

activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `_run__35606540​​18285941260__call__3098371293035639072__callbacks'

activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'

activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'

activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'

actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:27:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/reloader.rb:65:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'

railties (3.2.8) lib/rails/rack/logger.rb:26:in `call_app'

railties (3.2.8) lib/rails/rack/logger.rb:16:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/request_id.rb:22:in `call'

rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'

rack (1.4.1) lib/rack/runtime.rb:17:in `call'

activesupport (3.2.8) lib/active_support/cache/strategy/local_cache.rb:72:in `call'

rack (1.4.1) lib/rack/lock.rb:15:in `call'

actionpack (3.2.8) lib/action_dispatch/middleware/static.rb:62:in `call'

railties (3.2.8) lib/rails/engine.rb:479:in `call'

railties (3.2.8) lib/rails/application.rb:223:in `call'

rack (1.4.1) lib/rack/content_length.rb:14:in `call'

railties (3.2.8) lib/rails/rack/log_tailer.rb:17:in `call'

机架 (1.4.1) lib/rack/handler/webrick.rb:59:in `service'

/Users/aaronmacy/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `服务'

/Users/aaronmacy/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:94:在“运行”中

/Users/aaronmacy/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

编辑 3： users_controller.rb：

class UsersController < ApplicationController

  def show
    @user = User.find(params[:id])
  end

  def new
  end
end

用户.rb：

class User < ActiveRecord::Base
  attr_accessible :name, :email, :password, :password_confirmation
  has_secure_password

  before_save { self.email.downcase! }

  validates :name, presence: true, length: { maximum: 50 }
  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
  validates :email, presence:   true,
                    format:     { with: VALID_EMAIL_REGEX },
                    uniqueness: { case_sensitive: false }
  validates :password, presence: true, length: { minimum: 6 }
  validates :password_confirmation, presence: true
end

路线.rb：

SampleApp::Application.routes.draw do
  resources :users

  root to: 'static_pages#home'

  match '/signup',  to: 'users#new'

  match '/help',    to: 'static_pages#help'
  match '/about',   to: 'static_pages#about'
  match '/contact', to: 'static_pages#contact'
end
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1 回答 1

1

这是一个 bcrypt 问题。确认您在 Gemfile 中取消了 bcrypt 的注释，运行bundle install，然后重新启动服务器。

请参阅： 未定义的方法“键？” 对于 nil:NilClass 与 bcrypt-ruby 和 has_secure_password

于 2012-10-09T02:56:36.237 回答