Question

我正在建立一个现有的Ruby on Rails＆＃39;在数据库设置终端命令＆＃39; rails server＆＃39;之后投影到我的本地机器成功执行，但当我在浏览器中点击localhost：3000时，我得到以下响应....

Started GET "/" for 127.0.0.1 at 2014-04-08 16:07:01 +0530
  Processing by ContentController#index as HTML
  RvClass Load (0.1ms)  SELECT "rv_classes".* FROM "rv_classes" 
  Testimonial Load (0.2ms)  SELECT "testimonials".* FROM "testimonials" WHERE "testimonials"."approved" = 't'
  Setting Load (0.2ms)  SELECT "settings".* FROM "settings" LIMIT 1
Completed 500 Internal Server Error in 1136ms

NoMethodError (undefined method `features' for nil:NilClass):
  app/controllers/content_controller.rb:18:in `index'

content_controller.rb：

class ContentController < ApplicationController
  layout "application"
  before_filter :check_for_mobile, :except => [:inventory, :disclaimer, :preowned, :sunridge_rv_video]
  before_filter :prepare_for_mobile, :only => [:inventory, :social_media ]

  def inventory
  end

 def social_media
 end

 def index
   @tweets =  begin
                Twitter.user_timeline("sunridgeRV").slice(0, 6)
              rescue Twitter::Error
                []
              end
   @feature_products = Setting.first.features.where("product_id is not null")
   @home_page_testimonials = Testimonial.where(:approved=>true).shuffle.take(3)
   @setting = Setting.first
   @products = Product.where(special_on_homepage: true)
 end

 def disclaimer
   render :partial => 'disclaimer'
 end

 def preowned
   render :partial => 'used_guarantee'
 end

 def sunridge_rv_video
   @rv_class_brands = RvClassBrand.has_video_link
 end

 def sunridge_team
   @team_members = TeamMember.order("department_id").order("id")
 end

 def sales_home
   @setting = Setting.first
 end
end

Answer 1

问题在于这一行：

@feature_products = Setting.first.features.where("product_id is not null")

在features上调用Setting.first方法，您会收到错误，因为Setting.first返回 nil （这意味着您的设置表现在是空的），在这种情况下，在Setting.first上调用功能方法就像调用：nil.features

有些人建议你填写你的数据库行，但我认为这不是解决这个问题的方法，任何应用程序应该在没有任何现有数据的情况下工作

要解决上述问题，您应该添加如下条件：

@feature_products = Setting.first.features.where("product_id is not null") unless Setting.first.nil?

或使用try方法：

@feature_products = Setting.first.try(:features).where("product_id is not null")

希望这个帮助

将现有Ruby On Rails项目设置为本地计算机时出错

1 个答案: