我的圖片正在上傳，但似乎無處可見（它根本沒有顯示） - 不知道我哪里出錯了

Question

目前使用PaperClip上傳圖像文件。 在我的表單中，我可以輕松更新/編輯或創建新的列表。 當我上傳圖片時，它只會顯示為斷開的鏈接，當我點擊“在新標簽中打開圖片”時，我會收到一條消息：

沒有路線匹配[GET]“/assets/images/missing.png

我完全陷入困境，不知道接下來該做什么。 如果有人能提出一些關於該怎么做的建議或提示，真的很感激嗎？

編輯：

這是我的控制器：

class ListingsController < ApplicationController
  before_action :set_listing, only: [:show, :edit, :update, :destroy]

  # GET /listings
  # GET /listings.json
  def index
    @listing = Listing.all
  end

  # GET /listings/1
  # GET /listings/1.json
  def show
  end

  # GET /listings/new
  def new
    @listing = Listing.new
  end

  # GET /listings/1/edit
  def edit
  end

  # POST /listings
  # POST /listings.json
  def create
    @listing = Listing.create( listing_params )
    respond_to do |format|
      if @listing.save
        format.html { redirect_to @listing, notice: 'Listing was successfully created.' }
        format.json { render action: 'show', status: :created, location: @listing }
      else
        format.html { render action: 'new' }
        format.json { render json: @listing.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /listings/1
  # PATCH/PUT /listings/1.json
def update
    @listing = Listing.find(params[:id]) #find item you want to update
    respond_to do |format|
      if @listing.update_attributes(listing_params[:id]) # the refer to it and update it
        format.html { redirect_to @listing, notice: 'Listing was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @listing.errors, status: :unprocessable_entity }
    end
  end
end 



  # DELETE /listings/1
  # DELETE /listings/1.json
  def destroy
    @listing.destroy
    respond_to do |format|
      format.html { redirect_to listings_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_listing
      @listing = Listing.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def listing_params
      params.require(:listing).permit(:name, :description, :price, :image)
    end
end

這是我的模型 - 我只是想首先上傳文件，無論大小。

class Listing < ActiveRecord::Base
  has_attached_file :image, 
                    :styles => { :medium => "200x200", :thumb => "100x100>" }
end

這是我的開發日志：

Started GET "/assets/turbolinks.js?body=1" for 127.0.0.1 at 2014-06-09 00:23:48 +0100


Started GET "/assets/listings.js?body=1" for 127.0.0.1 at 2014-06-09 00:23:48 +0100


Started GET "/assets/pages.js?body=1" for 127.0.0.1 at 2014-06-09 00:23:48 +0100


Started GET "/assets/application.js?body=1" for 127.0.0.1 at 2014-06-09 00:23:48 +0100


Started GET "/images/original/missing.png" for 127.0.0.1 at 2014-06-09 00:23:48 +0100

ActionController::RoutingError (No route matches [GET] "/images/original/missing.png"):
  actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
  railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
  railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
  activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged'
  activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged'
  activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged'
  railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
  rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
  rack (1.5.2) lib/rack/runtime.rb:17:in `call'
  activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
  rack (1.5.2) lib/rack/lock.rb:17:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
  railties (4.0.0) lib/rails/engine.rb:511:in `call'
  railties (4.0.0) lib/rails/application.rb:97:in `call'
  rack (1.5.2) lib/rack/lock.rb:17:in `call'
  rack (1.5.2) lib/rack/content_length.rb:14:in `call'
  rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
  C:/Ruby200/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
  C:/Ruby200/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
  C:/Ruby200/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'


  Rendered C:/Ruby200/lib/ruby/gems/2.0.0/gems/actionpack-     4.0.0/lib/action_dispatch/middleware/templates/rescues/_trace.erb (2.0ms)
  Rendered C:/Ruby200/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/routes/_route.html.erb (2.0ms)
  Rendered C:/Ruby200/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/routes/_table.html.erb (1.0ms)
  Rendered C:/Ruby200/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/routing_error.erb within rescues/layout   (116.0ms)

Answer 1

HI @USERsomenumbers ...

在Parperclip的Documetation中 。 他們展示了一個如何看待你的模型的例子（listing.rb）

class Listing < ActiveRecord::Base
  has_attached_file :image, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "http://i.kinja-img.com/gawker-media/image/upload/s--iEV2_cUo--/c_fill,fl_progressive,g_north,h_77,q_80,w_137/akjmndys0n7jgpfmf41d.jpg"
end

:default_url選項代表替換，以防用戶沒有上傳圖像，如果你沒有在你的模型中寫它，它將有一個默認的網址（ '/images/thumb/missing.png' ...或類似的東西）但你會有一個錯誤，因為你的應用程序中沒有路由（鏈接）有該文件。 因此，您應始終編寫默認URL或添加驗證（：presence true）以強制用戶上載圖像

另外......要驗證您的應用是否確實保存了您的上傳內容，您應該登錄控制台（ rails c -s ）和Listing.last

2.1.0 :001 > Listing.last
  Listing Load (0.3ms)  SELECT "listings".* FROM "listings" ORDER BY "listings"."id" DESC LIMIT 1
 => #<Listing id: 3, name: "34", description: "54", price: #<BigDecimal:93f0120,'0.77E2',9(27)>, created_at: "2014-06-09 06:02:20", updated_at: "2014-06-09 06:02:20", image_file_name: nil, image_content_type: nil, image_file_size: nil, image_updated_at: nil> 

正如您所看到的所有開頭的符號:image該值為nil ，這意味着用戶沒有上傳圖像，並且rails將查找在以下設置中設置的圖像:default_url

你也應該在_form.html.erb上有這一行

<%= form_for @listing,  :url => listings_path, :html => { :multipart => true } do |f| %>

Answer 2

我不確定rails是否保存了圖像路徑

Rails / Paperclip不會保存圖像路徑 - Paperclip將有一個文件夾/文件結構，它將保存您需要的文件（默認為public/system ）

Paperclip通過獲取您的文件，將其轉換為對象並將以下信息保存到您的數據庫來工作：

• attachment_file_name
• attachment_content_type
• attachment_file_size
• attachment_updated_at

這意味着您的問題不太可能是Paperclip缺少image path 。 Paperclip實際上只是一種將圖像對象附加到記錄中的方法，允許您執行以下操作：

@post = Post.find 1
@post.image.url

---

驗證

我認為您的問題與您的驗證有關

Paperclip 4引入了一種新類型的驗證，它在上傳之前檢查文件欺騙（基本上檢查文件類型）。 解決此問題的方法是使用以下驗證：

#app/models/listing.rb
class Listing < ActiveRecord::Base
  has_attached_file :image, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/:style/missing.png"
  validates_attachment_content_type :image, :content_type => /\Aimage\/.*\Z/
end

你的其他代碼看起來不錯 - 我建議問題是你的文件沒有被正確驗證，導致它沒有得到保存。 要么是這樣，要么是你錯誤地調用了文件