如何将文件从 HTML5 拖放到 Rails 3 应用程序和回形针?

Right now the only way I can get this working is by sending an XMLHttpRequest with the File data and having my Rails action read the request.raw_post ... this isn't a workable solution because I need to send along additional POST params and the authenticity token.

这是我目前所拥有的:

<!-- IN MY VIEW -->
<h2>Drag and drop upload</h2>

<div id="drop">
  <h2>Drop Files Here</h2>
</div>

<script type="text/javascript" charset="utf-8">
  var dropbox = document.getElementById("drop");  
  drop = function(evt) {   
    evt.stopPropagation();
    evt.preventDefault();
    var files = evt.dataTransfer.files;
    var count = files.length;
    if (count > 0) {
        // handleFiles(files);
      var url = '/images/raw';
      var request = new XMLHttpRequest();
      request.open("POST",  url, true); // open asynchronous post request
      request.send(files[0]);
    }
  }
  dragEnter = function(evt) {
    evt.stopPropagation();
    evt.preventDefault();
  }
  dragExit = function(evt) {
    evt.stopPropagation();
    evt.preventDefault();
  }
  dragOver = function(evt) {
    evt.stopPropagation();
    evt.preventDefault();
  }
  // init event handlers
  dropbox.addEventListener("dragenter", dragEnter, false);
  dropbox.addEventListener("dragexit", dragExit, false);
  dropbox.addEventListener("dragover", dragOver, false);
  dropbox.addEventListener("drop", drop, false);
</script>

还有我的控制器操作:

class ImagesController < ApplicationController

  # ... Normal REST actions 

  def raw
    name = "tmp_image.png"
    data = request.raw_post
    @file_content = File.open("#{Rails.root.to_s}/tmp/#{name}", "wb") do |f| 
      f.write(data)
    end
    @image = Image.new(:attachment => File.new("#{Rails.root.to_s}/tmp/#{name}"))
    @image.save
    File.unlink("#{Rails.root.to_s}/tmp/#{name}")
    render :text => 'success'    
  end
end

那么，使用附加参数将拖放文件发布到我的应用程序的正确方法是什么?