ActionView :: Template :: Error（沒有路由匹配{：action =>「show」，：controller =>「categories」，：id => nil}缺少必需的鍵：[：id]）：

Question

我知道那裏這裏有很多關於類似問題的帖子，但是他們都沒有幫助我。

我在使用Capistrano/passenger到production mode在VPS上部署後，我的應用在localhost上運行很好我收到此錯誤。我沒有改變代碼，控制器或路由中的任何東西......所以我不知道爲什麼我得到這個錯誤。

任何人都可以幫助我嗎？

**編輯**

是否有可能，這個錯誤發生的事情，因爲我destroyed類別ID爲1-8的VPS。

如果我登錄到rails console這是在category

Category Load (0.6ms) SELECT "categories".* FROM "categories" 
=> #<ActiveRecord::Relation [#<Category id: 9, name: "Beauty & Fragrance", created_at: "2016-09-30 10:43:54", updated_at: "2016-10-04 16:35:41">, # <Category id: 10, name: "Jewellery", created_at: "2016-10-04 16:36:40", updated_at: "2016-10-04 16:36:40">, #<Category id: 11, name: "Home Decor", created_at: "2016-10-04 16:37:13", updated_at: "2016-10-04 16:37:13">, # <Category id: 12, name: "Giftwrap and Cards", created_at: "2016-10-04 16:37:42", updated_at: "2016-10-04 16:37:42">]> 

中的項目，是有可能的是，在指數的代碼與ID尋找類項目1至....？

** **更新

當我運行Product.where(category_id: [*1..8])我得到Product Load (0.9ms) SELECT "products".* FROM "products" WHERE "products"."category_id" IN (1, 2, 3, 4, 5, 6, 7, 8) => #<ActiveRecord::Relation []>

所以這是最有可能不是爲什麼這個錯誤是顯示

這是從production.log

ActionView::Template::Error (No route matches {:action=>"show", :controller=>"categories", :id=>nil} missing required keys: [:id]): 
23:           <% if index == 0 %> 
24:           <div class="col-lg-4 col-sm-6 col-xs-12 center-block " > 
25:         
26:             <%= link_to category_path (category) do %> 
27:               <%= image_tag product.image.url(:medium), class: "img-responsive" %> 
28:             <% end %> 
29:         <div class="caption"> 
app/views/pages/index.html.erb:26:in `block (3 levels) in _app_views_pages_index_html_erb___619502042981659248_47242510413860' 
app/views/pages/index.html.erb:22:in `each' 
app/views/pages/index.html.erb:22:in `each_with_index' 
app/views/pages/index.html.erb:22:in `block (2 levels) in _app_views_pages_index_html_erb___619502042981659248_47242510413860' 
app/views/pages/index.html.erb:20:in `each' 
app/views/pages/index.html.erb:20:in `block in _app_views_pages_index_html_erb___619502042981659248_47242510413860' 
app/views/pages/index.html.erb:18:in `each' 
app/views/pages/index.html.erb:18:in `each_slice' 
app/views/pages/index.html.erb:18:in `_app_views_pages_index_html_erb___619502042981659248_47242510413860' 

這裏是來自`pages_controller.rb的索引方法

def index 
    @products = Product.all.order(created_at: :desc).group_by(&:category_id) 
    @images = ["1.jpg", "2.jpg", "3.jpg", "4.jpg", "5.jpg", "6.jpg", "7.jpg", "8.jpg", "9.jpg", "10.jpg"] 
    @random_no = rand(10) 
    @random_image = @images[@random_no] 
end 

這裏是categories_controller.rb

class CategoriesController < ApplicationController 
    before_action :set_category, only: [:show, :edit, :update, :destroy] 
def index 
    @categories = Category.all 
end 

def show 
    @products = @category.products 
    @images = ["1.jpg", "2.jpg", "3.jpg", "4.jpg", "5.jpg"] 
    @random_no = rand(5) 
    @random_image = @images[@random_no] 
end 

private 
    def set_category 
    @category = Category.includes(:products).find(params[:id]) 
    end 

    def category_params 
    params.require(:category).permit(:name) 
    end 

end 

這裏是pages/index.html.erb

<div class="container-fluid"> 


    <% @products.each_slice(3) do |products_group| %> 
    <div class="row"> 
     <% products_group.each do |category, products| %> 

      <% products.each_with_index do |product, index| %> 
       <% if index == 0 %> 
        <div class="col-lg-4 col-sm-6 col-xs-12 center-block " > 

        <%= link_to category_path (category) do %> 
         <%= image_tag product.image.url(:medium), class: "img-responsive" %> 
        <% end %> 
      <div class="caption"> 
       <p class="category-name" ><%= product.category.name %></p> 
      </div> 
      <% end %> 
      <% end %> 
      </div> 
     <% end %> 
     </div> 
    <% end %> 

</div> 

這裏是config/routes.rb

Rails.application.routes.draw do 

get 'products/search' => 'products#search', as: 'search_products' 
post 'emaillist/subscribe' => 'emaillist#subscribe' 
resources :categories 
resources :labels 
resources :products do 
    resources :product_items 
end 

resources :carts 

resources :orders 

devise_for :admin_users, ActiveAdmin::Devise.config 
ActiveAdmin.routes(self) 

resources :contacts, only: [:new, :create] 

    root 'pages#index' 


get 'about' => 'pages#about' 

get 'location' => 'pages#location' 

get 'help' => 'pages#help' 

end 

這裏是耙潰敗的category部分ES

 categories GET  /categories(.:format)         categories#index 
          POST  /categories(.:format)         categories#create 
       new_category GET  /categories/new(.:format)        categories#new 
      edit_category GET  /categories/:id/edit(.:format)       categories#edit 
        category GET  /categories/:id(.:format)        categories#show 
          PATCH  /categories/:id(.:format)        categories#update 
          PUT  /categories/:id(.:format)        categories#update 
          DELETE  /categories/:id(.:format)        categories#destroy 

正如我說，這之前在本地主機的正常使用，我完全空白的，爲什麼它不工作相同的VPS

Answer 1

它仍然看起來像你有一個產品對象category_id，但也許那個Category對象不見了。

我想通過查找具有nil類別的產品來排除這一點。肯定是有寫這更優雅的方式，但它看起來像你沒有太多的對象在數據庫中，現在，所以這可能工作：

在您的VCS控制檯：

Product.all.map { |p| {p.id => p.category} } 

這會告訴你產品的ID，如果有的話，它是否指向一個類別或無。