使用CarrierWave上传RESTful文件 [英] RESTful file uploads with CarrierWave

问题描述

我试图建立一个API后端文件上传。我希望能够上传具有该文件的Base64编码字符串的POST请求的文件。服务器应解码字符串，并使用CarrierWave保存文件。这是我到目前为止：

photo.rb：

 类Photo 
包含Mongoid :: Document 
包含Mongoid :: Timestamps 
 mount_uploader：image_file，ImageUploader 
 end 
   
 
 
 image_uploader.rb： 
 
 
  class ImageUploader< CarrierWave :: Uploader :: Base 
 storage：file 
 
 def store_dir 
uploads /＃{model.class.to_s.underscore} /＃{mounted_as} /＃{model .id}
 end 
 end 
  
 Rails控制台：
 （summary） 
 
 
  ruby​​-1.8.7-p334：001> img = File.open（../ image.png）{| i | i.read} 
 => \377   JFIF\000\001\002\001\000H\000H\000\000\377 Photoshop3.0\0008BIM\003 ... 
 ruby​​-1.8.7-p334：003> encoded_img = Base64.encode64 img 
 => 3af8A \\\
mLpplt5U8q + a7G2 ... 
 ruby​​-1.8.7-p334：005> p = Photo.new 
 =>＃< Photo_id：4e21b9a31d41c817b9000001，created_at：nil，updated_at：nil，_type：nil，user_id：nil，image_file_filename：nil> 
 ruby​​-1.8.7-p334 ：006> p.user_id = 1 
 => 1 
 ruby​​-1.8.7-p334：007> p.image_file = Base64.decode64 encoded_img 
\255  = \254\2007u\226\230-zhwT\253％\036ʉs\232IsM\215˿6\247\ 256 \177 ... 
 ruby​​-1.8.7-p334：008> p.save 
 => true 
 ruby​​-1.8.7-p334：009> p。 image_file.url 
 => nil 
  
  full   
 
 
这个问题似乎与将Base64解码的字符串转换为文件的过程有关。CarrierWave似乎期望File对象，而是给它一个String。那么如何将该字符串转换为File对象。我希望这种转换不会将任何内容保存到文件系统中，只需创建该对象，然后让CarrierWave完成剩下的工作。
 > CarrierWave也接受一个StringIO，但是它需要一个 original_filename 方法，因为它需要它来计算文件名并进行扩展检查。如何在Rails 2和3之间进行更改，这里有两种方法：
 $ b $ Rails 2 
 
 $ $ $ $ $ $  io = StringIO.new（Base64.decode64（encoded_img））
 io.original_filename =foobar.png
 
 p.image_file = io 
 p .save 
  

在Rails 3中，您需要创建一个新类，然后手动添加 original_filename 返回

  class FilelessIO< StringIO 
 attr_accessor：original_filename 
 end 
 $ b $ i = FilelessIO.new（Base64.decode64（encoded_img））
 io.original_filename =foobar.png
 
 p.image_file = io 
 p.save 
  

I'm trying to build an API backend for file uploads. I want to be able to upload files with a POST request that has a Base64-encoded string of the file. The server should decode the string, and save the file using CarrierWave. Here's what I have so far:

photo.rb:

class Photo
  include Mongoid::Document
  include Mongoid::Timestamps
  mount_uploader :image_file, ImageUploader
end

image_uploader.rb:

class ImageUploader < CarrierWave::Uploader::Base
  storage :file

  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end
end

Rails console: (summary)

ruby-1.8.7-p334 :001 > img = File.open("../image.png") {|i| i.read}
 => "\377���JFIF\000\001\002\001\000H\000H\000\000\377�Photoshop 3.0\0008BIM\003...
ruby-1.8.7-p334 :003 >   encoded_img = Base64.encode64 img
=> 3af8A\nmLpplt5U8q+a7G2...
ruby-1.8.7-p334 :005 >   p = Photo.new
 => #<Photo _id: 4e21b9a31d41c817b9000001, created_at: nil, updated_at: nil, _type: nil, user_id: nil, image_file_filename: nil> 
ruby-1.8.7-p334 :006 > p.user_id = 1
 => 1 
ruby-1.8.7-p334 :007 > p.image_file = Base64.decode64 encoded_img
\255��=\254\200�7u\226���\230�-zh�wT\253%����\036ʉs\232Is�M\215��˿6\247\256\177...
ruby-1.8.7-p334 :008 > p.save
 => true 
ruby-1.8.7-p334 :009 > p.image_file.url
 => nil 

full

The problem appears to be related to the process of converting a Base64-decoded string to a file. CarrierWave seems to expect a File object, and instead I'm giving it a String. So how do I convert that String to a File object. I'd like this conversion not to save anything to the file system, simply create the object and let CarrierWave do the rest.

解决方案

CarrierWave also accepts a StringIO, but it expects a original_filename method, since it needs it for figuring out the file name and doing the extension check. How you do it changed between Rails 2 and 3, here's both methods:

Rails 2

io = StringIO.new(Base64.decode64(encoded_img))
io.original_filename = "foobar.png"

p.image_file = io
p.save

In Rails 3, you need to make a new class and then manually add original_filename back

class FilelessIO < StringIO
    attr_accessor :original_filename
end

io = FilelessIO.new(Base64.decode64(encoded_img))
io.original_filename = "foobar.png"

p.image_file = io
p.save

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