无法批量分配受保护的属性：_destroy

Question

当我提交嵌套表单时，我遇到了这个非常奇怪的错误。

Can't mass-assign protected attributes: _destroy

知道为什么会这样吗？这有点令人担忧，因为我必须暂时删除 javascript 的"销毁"hidden_field，直到我弄清楚它是什么，这意味着我无法删除任何内容！

_form.html.erb

<%= nested_form_for(@post, :html=> {:multipart => true, :class=> "new_blog_post", :id=> "new_blog_post"}) do |f| %>
 <%= field do %>
    <%= f.text_field :title, placeholder: "Give your post a title", :class=>"span12" %>
 <% end %>
 <%= field do %>
    <%= f.text_area :body, placeholder: "Write something here...", :id=>"blog-text", :class=>"span12" %>
 <% end %>
 <%= f.label :search_locations, "Add locations to your post" %>
    <%= text_field_tag :name,"",:class=>"localename", :id=>"appendedInput", :placeholder=> "Name of the location", :autocomplete => "off" %>
    <%= f.link_to_add "Add a location", :locations %>
 <%= actions do %>
   <%= f.submit "Submit", :class=>"btn", :disable_with => 'Uploading Image...' %>
<% end end%>

_posts_controller.rb_

class PostsController < ::Blogit::ApplicationController   
...   
def new
  @post = current_blogger.blog_posts.new(params[:post])
  @location = @post.locations.build
end

def edit
  @post = Post.find(params[:id])
  #@post = current_blogger.blog_posts.find(params[:id]) removed so any use can edit any post
  @location = @post.locations.build
end

def create
   location_set = params[:post].delete(:locations_attributes) unless params[:post][:locations_attributes].blank?
   @post = current_blogger.blog_posts.new(params[:post])
   @post.locations = Location.find_or_initialize_location_set(location_set) unless location_set.nil?

 if @post.save
    redirect_to @post, notice: 'Blog post was successfully created.'
  else
    render action: "new"
  end
end

def update
  @post = current_blogger.blog_posts.find(params[:id])
  if @post.update_attributes(params[:post])
    redirect_to @post, notice: 'Blog post was successfully updated.'
  else
    render action: "edit"
  end
end
def destroy
  @post = current_blogger.blog_posts.find(params[:id])
  @post.destroy
  redirect_to posts_url, notice: "Blog post was successfully destroyed."
end

位置.rb

class Location < ActiveRecord::Base
  after_save { |location| location.destroy if location.name.blank? }
  has_many :location_post
  has_many :posts, :through => :location_post
  has_many :assets
   attr_accessible :latitude, :longitude, :name, :post_id, :notes, :asset, :assets_attributes
    accepts_nested_attributes_for :assets, :allow_destroy => true
    include Rails.application.routes.url_helpers

  def self.find_or_initialize_location_set(location_set)
   locations = []
   locations = locations.delete_if { |elem| elem.flatten.empty? }
   location_set.each do |key, location|
    locations << find_or_initialize_by_name(location)
  end
     locations
  end
 end

编辑：

新.html.erb 中呈现的表单片段

    <div class="row span locsearch">      
       <div class="input-append span3">
        <input autocomplete="off" class="localename" id="appendedInput" name="name" placeholder="Name of the location" type="text" value="">

        <span class="add-on"><input id="post_locations_attributes_0__destroy" name="post[locations_attributes][0][_destroy]" type="hidden" value="false"><a href="javascript:void(0)" class="remove_nested_fields" data-association="locations"><i class="icon-trash"></i></a></span>  </div>
<div class="latlong offset3 span4"> <p class="help-block">Enter the name of the town or city visited in this blog entry.</p>
        </div>
        <input class="LegNm" id="post_locations_attributes_0_name" name="post[locations_attributes][0][name]" type="hidden" value="Dresden">
        <input class="long" id="post_locations_attributes_0_longitude" name="post[locations_attributes][0][longitude]" type="hidden" value="13.7372621">
        <input class="lat" id="post_locations_attributes_0_latitude" name="post[locations_attributes][0][latitude]" type="hidden" value="51.0504088">
    </div>  
</div>

编辑2：

后.rb

class Post < ActiveRecord::Base
require "acts-as-taggable-on"
require "kaminari"
acts_as_taggable    
self.table_name = "blog_posts"
self.paginates_per Blogit.configuration.posts_per_page
# ==============
# = Attributes =
# ==============
attr_accessible :title, :body, :tag_list, :blogger_id, :coverphoto, :locations_attributes

# ===============
# = Photo Model =
# ===============

    has_attached_file :coverphoto,
                :styles => {
                  :coverbar => "600x300>", :medium => "250x250^" , :thumb => "100x100^"},
                  #:source_file_options =>  {:all => '-rotate "-90>"'},
                  :storage => :s3,
                  :s3_credentials => "#{Rails.root}/config/s3.yml",
                  :bucket => "backpackbug",
                  :path => "/:style/:id/:filename"                

# ===============
# = Validations =
# ===============
validates :title, presence: true, length: { minimum: 6, maximum: 66 }
validates :body,  presence: true, length: { minimum: 10 }
validates :blogger_id, presence: true

# =================
# = Associations =
# =================    
belongs_to :blogger, :polymorphic => true
has_many :location_post
has_many :locations, :through => :location_post
belongs_to :profile
accepts_nested_attributes_for :locations, :allow_destroy => true, :reject_if => proc { |attributes| attributes['name'].blank? }
end end

Answer 1

这是通过这个和另一个答案的组合来解决的，在这里找到：

如何修复此创建函数？

短期修复是添加 attr_accessible ：_destroy 和 attr_accessor ：_destroy。

谢谢两位！

Answer 2

将:_destroy添加到attr_accessible列表中

attr_accessible ...., :_destroy

Answer 3

你应该写信给post.rb，

 attr_accessible: locations_atributes

和

accepts_nested_attributes_for :locations, :allow_destroy => true

当您通过 POST 对象更新位置对象时。

Answer 4

替换f.hidden_field它必须保持这样（第 2 行）

 module ApplicationHelper
  def link_to_remove_fields(name, f)
    text_field_tag(:_destroy) + link_to_function(name, "remove_fields(this)")
  end