title: Handling large file uploads with Flask
body: <p>What would be the best way to handle very large file uploads (1 GB +) with Flask?</p>
  
  <p>My application essentially takes multiple files assigns them one unique file number and then saves it on the server depending on where the user selected.</p>
  
  <p><strong>How can we run file uploads as a background task so the user does not have the browser spin for 1hour and can instead proceed to the next page right away?</strong></p>
  
  <ul>
  <li>Flask development server is able to take massive files (50gb took 1.5 hours, upload was quick but writing the file into a blank file was painfully slow)</li>
  <li>If I wrap the app with Twisted, the app crashes on large files</li>
  <li>I've tried using Celery with Redis but this doesn't seem to be an option with posted uploads</li>
  <li>I'm on Windows and have fewer options for webservers </li>
  </ul>