Nested Set Error未定义方法`self_and_descendants'for＃< ActiveRecord :: Relation：0x52c4a30> [英] Nested Set Error undefined method `self_and_descendants' for #<ActiveRecord::Relation:0x52c4a30>

问题描述

我在我的代码中使用了Nested_Set gem来排序类别，子类别和产品。我试图限制我的嵌套集的深度/级别不会更深，然后2.目前我得到错误

 嵌套设置错误未定义的方法`self_and_descendants'为＃< ActiveRecord :: Relation：0x52c4a30> 
  

我正在尝试创建一个克制菜单式样式，并试图使其拖动

这是我的代码：
有人可以浏览它并帮助我理解这个错误吗？感谢
Category.rb

  class Category< ActiveRecord :: Base 
 acts_as_nested_set 
 acts_as_list：scope => ：parent_id 
 has_many：products 
 scope：category，其中（parent_id IS NULL）
 scope：子类别，其中（parent_id IS NOT NULL）
 scope：with_depth_below， lambda {| level | （self.arel_table [：depth] .lt（level））} 
 end 
  

categories_controller

  class CategoriesController< ApplicationController 
 def new 
 @category = params [：id]？ Category.find（params [：id]）。children.new：Category.new 
 @count = Category.count 
 end 
 $ b $ def new_subcategory 
 @category = params [：id]？ Category.find（params [：id]）。children.new：Category.new 
 @ category_2_deep = Category.with_depth_below（2）
 end 
 
 def create 
 @category = params [：id]？ Category.find（params [：id]）。children.new（params [：category]）：Category.new（params [：category]）
 if @ category.save 
 redirect_to products_path，：notice => 创建的类别！Woo Hoo！ 
 else 
渲染新
结束
结束
 
 def编辑
 @category = Category.find（params [：id]） 
 end 
 $ b def edit_subcategory 
 @category = Category.find（params [：id]）
 @ category_2deep = Category.with_depth_below（2）.arrange 
结束
 
 def破坏
 @category = Category.find（params [：id]）
 @ category.destroy 
 flash [：notice] =类别有被抹杀了！ 
 redirect_to products_path 
 end 
 $ b def update 
 @category = Category.find（params [：id]）
 if @ category.update_attributes（params [ ：category]）
 flash [：notice] =将它改为ya！ 
 redirect_to products_path 
 else 
 flash [：alert] =类别尚未更新。 
 render：action => edit
 end 
 end 
 
 def show 
 @category = Category.find（params [：id]）
 end 
 
 def index 
 end 
 
 def sort 
 params [：category] ​​.each_with_index do | id，index | 
 Category.update_all（{position：index + 1}，{id：id}）
 end 
 end 
 end 
  

Routes.rb

  Jensenlocksmithing :: Application.routes。 draw do 
 getlog_out=> sessions＃destroy，如：log_out
 getlog_in=> session＃new，如：log_in
获得site / home
获得site / about_us
获得site / faq
获得site / discounts 
获得site / services
获得site / contact_us
获得site / admin
获得site / posts
获得categories / new_subcategory 
 getcategories / edit_subcategory
 
资源：用户
资源：会话
资源：优惠券
资源：monthly_posts 
资源：类别do 
 collection {post：sort} 
 resources：children，：controller => ：类别，：仅限=> [：index，：new，：create，：new_subcategory] ​​
结束
资源：子类别
资源：产品
资源：评论
资源：faqs do 
 collection {post：sort} 
 end 
 
 root to：'site＃home'
 end 
  

categories / form.html.erb

 <％= form_for（@类别）do | f | ％GT; 
 
< p> 
<％= f.label（：name）％> 
<％= f.text_field：name％> 
< / p> 
< p> 
<％= f.label（：parent_id）％> 
 <％= f.select：parent_id，nested_set_options（@ category_2_deep，@category）{| i，level | ＃{' - '* level if level< 1}＃{i.name if level <1}}％> 
 
< / p> 
< p> 
<％= f.label（：position）％> 
<％= f.select：position，1..category_count％> 
< / p> 
< p> 
<％= f.submit（提交）％> 
< / p> 
<％end％> 
  

解决方案

看起来像nested_set正在寻找一个Array类似数组的集合 - 请参阅源代码的第32行： https://github.com/skyeagle/nested_set/blob/21a009aec86911f5581147dd22de3c5d086355bb/lib/nested_set/helper.rb#L32

...因此它越来越ActiveRecord :: Relation将其封装在[数组]（第35行）中，然后尝试迭代并炸毁。

轻松修复 ：首先在集合上调用 to_a - 在您的控制器中：

  @ category_2_deep = Category.with_depth_below（2）.to_a 
  

更好的解决方法：submit给维护者一个补丁，它更像Ruby，并且它看起来像一个Array，但不一定是一个。

I am using the Nested_Set gem in my code to sort Categories, Subcategories, and Products. I am trying to limit the depth/level of my nested set to no deeper then 2. Currently I am getting the error

Nested Set Error undefined method `self_and_descendants' for #<ActiveRecord::Relation:0x52c4a30> 

I am trying to create a restraunt menu type style, and am going to attempt to make it drag and drop sortable.

Here is my code: Can someone browse it and help me understand this error? Thanks Category.rb

class Category < ActiveRecord::Base
  acts_as_nested_set
  acts_as_list :scope => :parent_id
  has_many :products
  scope :category, where("parent_id IS NULL")
  scope :subcategories, where("parent_id IS NOT NULL")
  scope :with_depth_below, lambda { |level| where(self.arel_table[:depth].lt(level)) }
end

categories_controller

class CategoriesController < ApplicationController
  def new
    @category = params[:id] ? Category.find(params[:id]).children.new : Category.new
    @count = Category.count
  end

  def new_subcategory
    @category = params[:id] ? Category.find(params[:id]).children.new : Category.new
    @category_2_deep = Category.with_depth_below(2)
  end

  def create
    @category = params[:id] ? Category.find(params[:id]).children.new(params[:category]) : Category.new(params[:category])
    if @category.save
      redirect_to products_path, :notice => "Category created! Woo Hoo!"
    else
      render "new"
    end
  end

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

  def edit_subcategory
    @category = Category.find(params[:id]) 
    @category_2deep = Category.with_depth_below(2).arrange
  end

  def destroy
    @category = Category.find(params[:id])
    @category.destroy
    flash[:notice] = "Category has been obliterated!"
    redirect_to products_path
  end

  def update
    @category = Category.find(params[:id])
    if @category.update_attributes(params[:category])
      flash[:notice] = "Changed it for ya!"
      redirect_to products_path
    else 
      flash[:alert] = "Category has not been updated."
      render :action => "edit"
    end
  end

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

  def index
  end

  def sort
    params[:category].each_with_index do |id, index|
      Category.update_all({position: index+1}, {id: id})
    end
  end
end

Routes.rb

Jensenlocksmithing::Application.routes.draw do
  get "log_out" => "sessions#destroy", as: "log_out"
  get "log_in" => "sessions#new", as: "log_in"
  get "site/home"
  get "site/about_us"
  get "site/faq"
  get "site/discounts"
  get "site/services"
  get "site/contact_us"
  get "site/admin"
  get "site/posts"
  get "categories/new_subcategory"
  get "categories/edit_subcategory"

  resources :users
  resources :sessions
  resources :coupons
  resources :monthly_posts
  resources :categories do
    collection { post :sort }
    resources :children, :controller => :categories, :only => [:index, :new, :create, :new_subcategory]
  end
  resources :subcategories
  resources :products
  resources :reviews
  resources :faqs do
    collection { post :sort }
  end 

  root to: 'site#home'
end

categories/form.html.erb

<%= form_for(@category) do |f| %>

<p>
<%= f.label(:name) %>
<%= f.text_field :name %>
</p>
<p>
<%= f.label(:parent_id) %>
<%= f.select :parent_id, nested_set_options(@category_2_deep, @category) {|i, level| "# {'-' * level if level < 1 } #{i.name if level < 1 }" } %>

</p>
<p>
<%= f.label(:position) %>
<%= f.select :position, 1..category_count %>
</p>
<p>
  <%= f.submit("Submit") %>
</p>
<% end %>

解决方案

It looks like nested_set is looking for an Array not just an array-like collection - see line 32 of the source: https://github.com/skyeagle/nested_set/blob/21a009aec86911f5581147dd22de3c5d086355bb/lib/nested_set/helper.rb#L32

...hence it's getting that ActiveRecord::Relation, wrapping it in an [array] (line 35) and then trying to iterate and blowing up.

Easy fix: call to_a on the collection first - in your controller:

@category_2_deep = Category.with_depth_below(2).to_a

Better fix: submit a patch to the maintainer that's a bit more Ruby-like and looks for it to behave like an Array, but not necessarily be one.

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