无法通过回形针在Windows 8的导轨中保存图像

Question

我使用"paperclip","〜> 4.1"(在Windows 8上)将图片保存到我的产品中.我有下面的代码:

products_controller:

class ProductsController < ApplicationController
  before_action :set_product, only: [:show, :edit, :update, :destroy]
  def index
    @products = Product.all
  end

  def show
  end

  def new
    @product = Product.new
  end
  def edit
    @product = Product.all
  end
  def create
    @product = Product.new(product_params)  
    respond_to do |format|
      if @product.save
        format.html { redirect_to @product, notice: 'Product was successfully created.' }
        format.json { render action: 'show', status: :created, location: @product }
      else
        format.html {
          render action: 'new'
        }
        format.json { render json: @product.errors, status: :unprocessable_entity }
      end
    end
  end

  def update
    respond_to do |format|
      if @product.update(product_params)
        format.html { redirect_to @product, notice: 'Product was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @product.errors, status: :unprocessable_entity }
      end
    end
  end

  def destroy
    @product.destroy
    respond_to do |format|
      format.html { redirect_to products_url }
      format.json { head :no_content }
    end
  end

  private

    def set_product
      @product = Product.find(params[:id])
    end

    def product_params
      params.require(:product).permit(:name, :code,:picture)
    end
end

product.rb

class Product < ActiveRecord::Base
  has_attached_file :picture, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/missing.png"
  validates_attachment_content_type :picture, :content_type => [ 'image/gif', 'image/png', 'image/x-png', 'image/jpeg', 'image/pjpeg', 'image/jpg' ]

end

但是当我想要保存我上传的图片时,我得到以下错误:

1 error prohibited this product from being saved:
Picture has an extension that does not match its contents

系统日志:

Started POST "/products" for 127.0.0.1 at 2014-05-04 23:23:31 +0430
Processing by ProductsController#create as HTML
  Parameters: {"utf8"=>"?", "authenticity_token"=>"XVKgrUjhmB6auJXM5zTrDFrw7GLS0jdUPFelXt4se4Y=", "product"=>{"name"=>"Product 453", "code"=>"324324", "category_id"=>"10", "describe"=>"", "picture"=>#<ActionDispatch::Http::UploadedFile:0x00000004fdb750 @tempfile=#<Tempfile:C:/Users/MGH~1.119/AppData/Local/Temp/RackMultipart20140504-5856-p42svx>, @original_filename="pic.jpg", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"product[picture]\"; filename=\"pic.jpg\"\r\nContent-Type: image/jpeg\r\n">}, "commit"=>"Save change"}
  User Load (1.0ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 17 ORDER BY "users"."id" ASC LIMIT 1
Command :: file -b --mime-type "C:/Users/MGH~1.119/AppData/Local/Temp/be0933fb4765581454c720c6cac4755920140504-5856-15ak6qf"
[paperclip] Content Type Spoof: Filename pic.jpg (["image/jpeg"]), content type discovered from file command: . See documentation to allow this combination.
  Responsibility Load (0.0ms)  SELECT "responsibilities".* FROM "responsibilities" WHERE "responsibilities"."user_id" = ? ORDER BY "responsibilities"."id" ASC LIMIT 1  [["user_id", 17]]
   (1.0ms)  begin transaction
Command :: file -b --mime-type "C:/Users/MGH~1.119/AppData/Local/Temp/6db10b0624aa4c70237ca9e622c03f4620140504-5856-t1i2gw"
[paperclip] Content Type Spoof: Filename pic.jpg (["image/jpeg"]), content type discovered from file command: . See documentation to allow this combination.
   (0.0ms)  rollback transaction
  Category Load (0.0ms)  SELECT "categories".* FROM "categories"
  Rendered products/_form.html.erb (2.0ms)
  Rendered products/new.html.erb within layouts/product (3.0ms)
  Rendered layouts/_header.html.erb (0.0ms)
  Rendered layouts/_sidebar.erb (0.0ms)
Completed 200 OK in 159ms (Views: 16.0ms | ActiveRecord: 2.0ms)

问题出在哪儿？

如何将pdf文件保存到paperclip视图中并显示？

Answer 1

Paperclip在v4.0中引入了欺骗验证,以确保文件内容与扩展名匹配.

它使用该file命令来确定文件的MIME类型,如果你使用linux或OS X就可以了.不幸的是,Windows没有file命令所以它返回空白 - 因为这与预期的MIME类型不匹配根据其扩展名文件,您会收到欺骗错误.

你的日志中的这一点:

content type discovered from file command: .

冒号和句号之间的位是file命令的输出; 在Windows上总是空白.

我所知道的Windows最佳解决方法是禁用欺骗.为此你需要在初始化器中放置这样的东西:

module Paperclip
  class MediaTypeSpoofDetector
    def spoofed?
      false
    end
  end
end