youtube_dl/downloader/dash.py

   1 from __future__ import unicode_literals
   2
   3 import os
   4
   5 from .fragment import FragmentFD
   6 from ..compat import compat_urllib_error
   7 from ..utils import (
   8     sanitize_open,
   9     encodeFilename,
  10 )
  11
  12
  13 class DashSegmentsFD(FragmentFD):
  14     """
  15     Download segments in a DASH manifest
  16     """
  17
  18     FD_NAME = 'dashsegments'
  19
  20     def real_download(self, filename, info_dict):
  21         segments = info_dict['fragments'][:1] if self.params.get(
  22             'test', False) else info_dict['fragments']
  23
  24         ctx = {
  25             'filename': filename,
  26             'total_frags': len(segments),
  27         }
  28
  29         self._prepare_and_start_frag_download(ctx)
  30
  31         segments_filenames = []
  32
  33         fragment_retries = self.params.get('fragment_retries', 0)
  34         skip_unavailable_fragments = self.params.get('skip_unavailable_fragments', True)
  35
  36         def process_segment(segment, tmp_filename, num):
  37             segment_url = segment['url']
  38             segment_name = 'Frag%d' % num
  39             target_filename = '%s-%s' % (tmp_filename, segment_name)
  40             # In DASH, the first segment contains necessary headers to
  41             # generate a valid MP4 file, so always abort for the first segment
  42             fatal = num == 0 or not skip_unavailable_fragments
  43             count = 0
  44             while count <= fragment_retries:
  45                 try:
  46                     success = ctx['dl'].download(target_filename, {
  47                         'url': segment_url,
  48                         'http_headers': info_dict.get('http_headers'),
  49                     })
  50                     if not success:
  51                         return False
  52                     down, target_sanitized = sanitize_open(target_filename, 'rb')
  53                     ctx['dest_stream'].write(down.read())
  54                     down.close()
  55                     segments_filenames.append(target_sanitized)
  56                     break
  57                 except compat_urllib_error.HTTPError as err:
  58                     # YouTube may often return 404 HTTP error for a fragment causing the
  59                     # whole download to fail. However if the same fragment is immediately
  60                     # retried with the same request data this usually succeeds (1-2 attemps
  61                     # is usually enough) thus allowing to download the whole file successfully.
  62                     # To be future-proof we will retry all fragments that fail with any
  63                     # HTTP error.
  64                     count += 1
  65                     if count <= fragment_retries:
  66                         self.report_retry_fragment(err, segment_name, count, fragment_retries)
  67             if count > fragment_retries:
  68                 if not fatal:
  69                     self.report_skip_fragment(segment_name)
  70                     return True
  71                 self.report_error('giving up after %s fragment retries' % fragment_retries)
  72                 return False
  73             return True
  74
  75         for i, segment in enumerate(segments):
  76             if not process_segment(segment, ctx['tmpfilename'], i):
  77                 return False
  78
  79         self._finish_frag_download(ctx)
  80
  81         for segment_file in segments_filenames:
  82             os.remove(encodeFilename(segment_file))
  83
  84         return True