title: File upload with Tornado
body: <p>How do I access the uploaded file in Tornado, when using a <code>put</code> request?</p>
  
  <pre><code>@require_basic_auth
  class UploadFile(tornado.web.RequestHandler):
      def put(self, params):
          path = calculate_path(params)
          # TODO: create an empty binary file at path and then copy 
          # the request input stream to it.
  </code></pre>