title: How to detect file size or video size when downloading with python if there no content length provided?
body: <p>I want to detect download link of video of file on google drive and get the size of these files before downloading but actually  content length is not provided. I've tried urllib and requests but the result is the same. By chance when the video page was open, IDM (internet download manager) detect the link and also the size.I want to know the idea or a solution to :</p>
  <ol>
  <li>file size before download</li>
  <li>detect link of download like IDM</li>
  </ol>