+ data = self.ydl.urlopen(request)
+ # When trying to resume, Content-Range HTTP header of response has to be checked
+ # to match the value of requested Range HTTP header. This is due to a webservers
+ # that don't support resuming and serve a whole file with no Content-Range
+ # set in response despite of requested Range (see
+ # https://github.com/rg3/youtube-dl/issues/6057#issuecomment-126129799)
+ if resume_len > 0:
+ content_range = data.headers.get('Content-Range')
+ if content_range:
+ content_range_m = re.search(r'bytes (\d+)-', content_range)
+ # Content-Range is present and matches requested Range, resume is possible
+ if content_range_m and resume_len == int(content_range_m.group(1)):
+ break
+ # Content-Range is either not present or invalid. Assuming remote webserver is
+ # trying to send the whole file, resume is not possible, so wiping the local file
+ # and performing entire redownload
+ self.report_unable_to_resume()
+ resume_len = 0
+ open_mode = 'wb'