http.py 文件源码

def next_chunk(self):
    """Get the next chunk of the download.

    Returns:
      (status, done): (MediaDownloadStatus, boolean)
         The value of 'done' will be True when the media has been fully
         downloaded.

    Raises:
      apiclient.errors.HttpError if the response was not a 2xx.
      httplib2.HttpLib2Error if a transport error has occured.
    """
    headers = {
        'range': 'bytes=%d-%d' % (
            self._progress, self._progress + self._chunksize)
        }
    http = self._request.http
    http.follow_redirects = False

    resp, content = http.request(self._uri, headers=headers)
    if resp.status in [301, 302, 303, 307, 308] and 'location' in resp:
        self._uri = resp['location']
        resp, content = http.request(self._uri, headers=headers)
    if resp.status in [200, 206]:
      self._progress += len(content)
      self._fd.write(content)

      if 'content-range' in resp:
        content_range = resp['content-range']
        length = content_range.rsplit('/', 1)[1]
        self._total_size = int(length)

      if self._progress == self._total_size:
        self._done = True
      return MediaDownloadProgress(self._progress, self._total_size), self._done
    else:
      raise HttpError(resp, content, uri=self._uri)