title: Flask video proxy-streaming doesn't let navigate through time bar
body: <p>I'm working on a <a href="https://github.com/pluja/Parasitter" rel="nofollow noreferrer">personal project</a> and I want to stream a video hosted on a platform (like Youtube) through the app server and to the client (VideoServer --&gt; MyApp --&gt; Client). The following function is the one I am using to do so, and it's working OK. I get the video streamed through my server to the client, but on the client I'm not able to navigate through the time bar of the video. I can't go forward and backwards on it. When I try to do so, the video jumps to the very beggining of it.</p>
  <p>I have made some research and I can't seem to find anything useful for this. I found <a href="https://stackoverflow.com/questions/57314357/streaming-video-files-using-flask">this other question</a> but it is using a local file instead of a file hosted on a remote server. I tried to set up something similar on my code but I can't get it to work. I think that the way of doing it should be similar to the solution of that question but I'm not really sure as I never worked with video streams before.</p>
  <pre><code>@app.route('/stream', methods=['GET'])
  @login_required
  def stream():
      id = request.args.get('v', None) # Get the video ID.
      url = getVideoUrl(id) # Get the video stream url.
      req = requests.get(url, stream = True)
      return Response(req.iter_content(chunk_size=10*1024), mimetype=req.headers['Content-Type'], content_type=req.headers['Content-Type'], direct_passthrough=True)
  </code></pre>