ruby-on-rails - friendly_id slugs 不断返回 nil 导致 ActiveRecord 错误

Question

我刚刚在我的博客中引入了类别，并且我已经对帖子进行了友好的处理。所以我决定也将它整合到类别中。问题是我不断收到错误 Couldn't find Category with 'id'=test-2 以及 ActiveRecord::RecordNotFound in CategoriesController#show 请理解我有尝试实现我在这里找到的许多解决方案，但我无法让它工作

class CategoriesController < ApplicationController

  before_action :find_category, only: [:show, :update, :edit, :destroy]

   def index
    @categories = Category.all
   end

  def new 
    @category = Category.new
  end

  def create
    @category = Category.new(category_params)
    if @category.save
      flash[:success] = "Category created"
      redirect_to categories_path

    else
      render 'new'
    end
  end

  def edit

  end

  def update
    if @category.update(category_params)
      flash[:success]="name was successfully updated"
      redirect_to category_path(@category)
    else
      render 'edit'
    end
  end

  def show

  end

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

  def find_category
    @category = Category.friendly.find(params[:id])
  end

end

现在奇怪的是，当我进入 Rails 控制台并尝试更新 slug 时，它显示如下:

Category.find_each(&:save)
  Category Load (0.3ms)  SELECT  "categories".* FROM "categories"  ORDER BY "categories"."id" ASC LIMIT 1000
   (0.1ms)  begin transaction
  Category Exists (0.1ms)  SELECT  1 AS one FROM "categories" WHERE ("categories"."id" != 1) AND "categories"."slug" = ? LIMIT 1  [["slug", "sports"]]

上面我们可以看到它说 slug, sports.. 这很好，但是当我找到时... slug 似乎是 nil，如下所示:

2.3.0 :058 > c = Category.find(1)
  Category Load (0.8ms)  SELECT  "categories".* FROM "categories" WHERE "categories"."id" = ? LIMIT 1  [["id", 1]]
 => #<Category id: 1, name: "sports", created_at: "2016-07-28 15:12:13", updated_at: "2016-07-28 15:12:13", slug: nil> 

我还试图通过尝试找到真正的 slug 来证实这一点:

2.3.0 :051 > Category.find(1).slug
  Category Load (0.2ms)  SELECT  "categories".* FROM "categories" WHERE "categories"."id" = ? LIMIT 1  [["id", 1]]
 => nil 

slug 似乎为零。

最后，以防万一它是相关的...这是我的 show.html.erb

<h1 align="center"><%= "Category: " + @category.name %></h1>
<div align = "center">
  <% if user_signed_in? %>
     <div id="admin_links">
       <%= link_to "Edit", edit_category_path(@category) %>
       <%= link_to "Delete", category_path(@category), method: :delete, data: {confirm: "Are you sure you want to delete?"} %>
     </div>
   <% end %>

   <%= link_to "Edit Category name", edit_category_path(@category) %>

</div>

这是category.rb

class Category < ActiveRecord::Base
  extend FriendlyId
  friendly_id :name, use: :slugged
  has_many :category_posts
  has_many :posts, through: :category_posts


  def should_generate_new_friendly_id?
    slug.blank? || name_changed?
  end
end

当我在控制台中执行 Category.first(5) 时，这就是结果

Category Load (0.3ms)  SELECT  "categories".* FROM "categories"  ORDER BY "categories"."id" ASC LIMIT 5
 => [#<Category id: 1, name: "sports", created_at: "2016-07-28 15:12:13", updated_at: "2016-07-28 15:12:13", slug: nil>,
    #<Category id: 2, name: "Nerd", created_at: "2016-07-28 17:33:35", updated_at: "2016-07-28 17:33:35", slug: nil>,
    #<Category id: 3, name: "testing", created_at: "2016-07-28 17:38:22", updated_at: "2016-07-28 17:39:23", slug: nil>,
    #<Category id: 4, name: "test 2", created_at: "2016-07-28 19:10:18", updated_at: "2016-07-28 19:10:18", slug: nil>,
    #<Category id: 5, name: "books", created_at: "2016-07-28 19:29:18", updated_at: "2016-07-28 19:29:18", slug: nil>

Answer 1

在您的 Category 模型中，您有 attr_accessor :slug，它将覆盖数据库中用于该字段的 setter 方法。这意味着 slug 字段将不会被保存。

从您的模型中删除 attr_accessor :slug + 再次重新创建实例以重新生成 slug。