Rails 3.2.11 Paperclip 多态嵌套附件，上传的图片永远不会保存！也许我应该为每个需要图像的表添加一个资产 ID？
什么会阻止回形针上传和保存文件？
谢谢先进
错误信息：
Connecting to database specified by database.yml
Started GET "/videos/" for 31.54.205.49 at Wed May 15 06:51:33 -0500 2013
Processing by VideosController#index as HTML
Rendered videos/index.html.erb within layouts/application (111.6ms)
Completed 500 Internal Server Error in 227ms
ActionView::Template::Error (undefined method `attachment_file_name' for #<Video::Cover:0x6929d69365c0>):
3: <div class="video">
4:
5: <%- video.covers.each do |cover| %>
6: <div class="video_cover"><%=link_to image_tag (cover.url(:small)), video %></div>
7: <% end %>
8:
9:
app/models/assets.rb:4:in `__send__'
app/models/assets.rb:4:in `url'
app/views/videos/index.html.erb:6:in `_app_views_videos_index_html_erb__730847823_57814209936840'
app/views/videos/index.html.erb:5:in `_app_views_videos_index_html_erb__730847823_57814209936840'
app/views/videos/index.html.erb:1:in `each'
app/views/videos/index.html.erb:1:in `_app_views_videos_index_html_erb__730847823_57814209936840'
app/controllers/videos_controller.rb:10:in `index'
架构：
ActiveRecord::Schema.define(:version => 20130514180732) do
create_table "assets", :force => true do |t|
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.string "type"
t.integer "assetable_id"
t.string "assetable_type"
t.string "attachement_type"
t.string "attachement_file_name"
t.string "attachement_content_type"
t.integer "attachement_file_size"
t.datetime "attachement_updated_at"
end
create_table "photos", :force => true do |t|
t.string "title"
t.text "body"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "videos", :force => true do |t|
t.string "title"
t.text "body"
t.string "url"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
end
楷模：
class Assets < ActiveRecord::Base
belongs_to :assetable, :polymorphic => true delegate :url, :to => :attachment
end
class Video < ActiveRecord::Base
attr_accessible :body, :title, :url, :assets_attributes, :cover
#has_many :images, :as => :assetable, :class_name => "Video::Image", :dependent => :destroy
has_many :covers, :as => :assetable, :class_name => "Video::Cover", :dependent => :destroy
accepts_nested_attributes_for :covers, :allow_destroy => true
class Video::Cover < Assets
has_attached_file :attachment, :styles => { :small => "300x0>", :large => "800x0>" }
end
end
视频控制器：
class VideosController < ApplicationController
#load_and_authorize_resource
# GET /videos
# GET /videos.xml
def index
@videos = Video.all
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => @videos }
end
end
# GET /videos/1
# GET /videos/1.xml
def show
@video = Video.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => @video }
end
end
# GET videos/new
# GET /videos/new.xml
def new
@video = Video.new
1.times do @video.covers.build end
#40.times do @video.images.build end
respond_to do |format|
format.html # new.html.erb
format.xml { render :xml => @video }
end
end
# GET /collections/1/edit
def edit
@video = Video.find(params[:id])
1.times do@video.covers.build end
#1.times do @video.images.build end
end
# POST /videos
# POST /videos.xml
def create
@video = Video.new(params[:video])
respond_to do |format|
if @video.save
format.html { redirect_to(@video, :notice => 'Video was successfully created.') }
format.xml { render :xml => @video, :status => :created, :location => @video }
else
format.html { render :action => "new" }
format.xml { render :xml => @video.errors, :status => :unprocessable_entity }
end
end
end
# PUT /videos/1
# PUT /videos/1.xml
def update
@video = Video.find(params[:id])
respond_to do |format|
if @video.update_attributes(params[:video])
format.html { redirect_to(@video, :notice => 'Video was successfully updated.') }
format.xml { head :ok }
else
format.html { render :action => "edit" }
format.xml { render :xml => @video.errors, :status => :unprocessable_entity }
end
end
end
# DELETE /videos/1
# DELETE /videos/1.xml
def destroy
@video = Video.find(params[:id])
@video.destroy
respond_to do |format|
format.html { redirect_to(videos_url) }
format.xml { head :ok }
end
end
end
视频形式：
<div id="form_bk">
<div id="field_left">
<%= form_for @video, :html => {:multipart => true} do |f| %>
<% if @video.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(@video.errors.count, "error") %> prohibited this collection from being saved:</h2>
<ul>
<% @video.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div id="cover">
<br />
<h2>Cover Image</h2>
<%= f.fields_for :covers do |cover| %>
<% if cover.object.new_record? %>
<p><%= cover.file_field :attachment %></p>
<% end %>
<% end %>
<%= f.fields_for :covers do |cover| %>
<% unless cover.object.new_record? %>
<br />
<p>
<%=image_tag cover.object.url(:small) %><br />
<br /> Delete cover <%= cover.check_box :_destroy %><br /><br />
</p>
<% end %>
<% end %>
</div>
<div id="form_right">
<div class="field">
<%= f.label :title %>
<%= f.text_field :title %>
</div>
<div class="field">
<%= f.label :body %><br />
<%= f.text_area :body %>
</div></div>
<div class="field">
<%= f.label :url %><br />
<%= f.text_area :url %>
</div></div>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
<br />
</div>
索引视图：
<% @videos.each do |video| %>
<div class="video">
<%= video.covers.each do |cover| %>
<div class="video_cover"><%=link_to image_tag (cover.url(:small)), video %></div>
<% end %>
<div class="video_title">
<%=link_to video.title, video %>
<%= video.body %>
<%= link_to 'Show', video %>
<%= link_to 'Edit', edit_video_path(video) %>
<%= link_to 'Destroy', video, :confirm => 'Are you sure?', :method => :delete %>
</div>
</div>
<% end %>
<br /><br /><br />
<%= link_to 'New Video', new_video_path %>