youtube_dl/downloader/fragment.py

   1 from __future__ import division, unicode_literals
   2
   3 import os
   4 import time
   5 import json
   6
   7 from .common import FileDownloader
   8 from .http import HttpFD
   9 from ..utils import (
  10     error_to_compat_str,
  11     encodeFilename,
  12     sanitize_open,
  13     sanitized_Request,
  14 )
  15
  16
  17 class HttpQuietDownloader(HttpFD):
  18     def to_screen(self, *args, **kargs):
  19         pass
  20
  21
  22 class FragmentFD(FileDownloader):
  23     """
  24     A base file downloader class for fragmented media (e.g. f4m/m3u8 manifests).
  25
  26     Available options:
  27
  28     fragment_retries:   Number of times to retry a fragment for HTTP error (DASH
  29                         and hlsnative only)
  30     skip_unavailable_fragments:
  31                         Skip unavailable fragments (DASH and hlsnative only)
  32     keep_fragments:     Keep downloaded fragments on disk after downloading is
  33                         finished
  34
  35     For each incomplete fragment download youtube-dl keeps on disk a special
  36     bookkeeping file with download state and metadata (in future such files will
  37     be used for any incomplete download handled by youtube-dl). This file is
  38     used to properly handle resuming, check download file consistency and detect
  39     potential errors. The file has a .ytdl extension and represents a standard
  40     JSON file of the following format:
  41
  42     extractor:
  43         Dictionary of extractor related data. TBD.
  44
  45     downloader:
  46         Dictionary of downloader related data. May contain following data:
  47             current_fragment:
  48                 Dictionary with current (being downloaded) fragment data:
  49                 index:  0-based index of current fragment among all fragments
  50             fragment_count:
  51                 Total count of fragments
  52
  53     This feature is experimental and file format may change in future.
  54     """
  55
  56     def report_retry_fragment(self, err, frag_index, count, retries):
  57         self.to_screen(
  58             '[download] Got server HTTP error: %s. Retrying fragment %d (attempt %d of %s)...'
  59             % (error_to_compat_str(err), frag_index, count, self.format_retries(retries)))
  60
  61     def report_skip_fragment(self, frag_index):
  62         self.to_screen('[download] Skipping fragment %d...' % frag_index)
  63
  64     def _prepare_url(self, info_dict, url):
  65         headers = info_dict.get('http_headers')
  66         return sanitized_Request(url, None, headers) if headers else url
  67
  68     def _prepare_and_start_frag_download(self, ctx):
  69         self._prepare_frag_download(ctx)
  70         self._start_frag_download(ctx)
  71
  72     @staticmethod
  73     def __do_ytdl_file(ctx):
  74         return not ctx['live'] and not ctx['tmpfilename'] == '-'
  75
  76     def _read_ytdl_file(self, ctx):
  77         stream, _ = sanitize_open(self.ytdl_filename(ctx['filename']), 'r')
  78         ctx['fragment_index'] = json.loads(stream.read())['downloader']['current_fragment']['index']
  79         stream.close()
  80
  81     def _write_ytdl_file(self, ctx):
  82         frag_index_stream, _ = sanitize_open(self.ytdl_filename(ctx['filename']), 'w')
  83         downloader = {
  84             'current_fragment': {
  85                 'index': ctx['fragment_index'],
  86             },
  87         }
  88         if ctx.get('fragment_count') is not None:
  89             downloader['fragment_count'] = ctx['fragment_count']
  90         frag_index_stream.write(json.dumps({'downloader': downloader}))
  91         frag_index_stream.close()
  92
  93     def _download_fragment(self, ctx, frag_url, info_dict, headers=None):
  94         fragment_filename = '%s-Frag%d' % (ctx['tmpfilename'], ctx['fragment_index'])
  95         success = ctx['dl'].download(fragment_filename, {
  96             'url': frag_url,
  97             'http_headers': headers or info_dict.get('http_headers'),
  98         })
  99         if not success:
 100             return False, None
 101         down, frag_sanitized = sanitize_open(fragment_filename, 'rb')
 102         ctx['fragment_filename_sanitized'] = frag_sanitized
 103         frag_content = down.read()
 104         down.close()
 105         return True, frag_content
 106
 107     def _append_fragment(self, ctx, frag_content):
 108         try:
 109             ctx['dest_stream'].write(frag_content)
 110         finally:
 111             if self.__do_ytdl_file(ctx):
 112                 self._write_ytdl_file(ctx)
 113             if not self.params.get('keep_fragments', False):
 114                 os.remove(ctx['fragment_filename_sanitized'])
 115             del ctx['fragment_filename_sanitized']
 116
 117     def _prepare_frag_download(self, ctx):
 118         if 'live' not in ctx:
 119             ctx['live'] = False
 120         self.to_screen(
 121             '[%s] Total fragments: %s'
 122             % (self.FD_NAME, ctx['total_frags'] if not ctx['live'] else 'unknown (live)'))
 123         self.report_destination(ctx['filename'])
 124         dl = HttpQuietDownloader(
 125             self.ydl,
 126             {
 127                 'continuedl': True,
 128                 'quiet': True,
 129                 'noprogress': True,
 130                 'ratelimit': self.params.get('ratelimit'),
 131                 'retries': self.params.get('retries', 0),
 132                 'nopart': self.params.get('nopart', False),
 133                 'test': self.params.get('test', False),
 134             }
 135         )
 136         tmpfilename = self.temp_name(ctx['filename'])
 137         open_mode = 'wb'
 138         resume_len = 0
 139
 140         # Establish possible resume length
 141         if os.path.isfile(encodeFilename(tmpfilename)):
 142             open_mode = 'ab'
 143             resume_len = os.path.getsize(encodeFilename(tmpfilename))
 144
 145         # Should be initialized before ytdl file check
 146         ctx.update({
 147             'tmpfilename': tmpfilename,
 148             'fragment_index': 0,
 149         })
 150
 151         if self.__do_ytdl_file(ctx):
 152             if os.path.isfile(encodeFilename(self.ytdl_filename(ctx['filename']))):
 153                 self._read_ytdl_file(ctx)
 154             else:
 155                 self._write_ytdl_file(ctx)
 156             if ctx['fragment_index'] > 0:
 157                 assert resume_len > 0
 158             else:
 159                 assert resume_len == 0
 160
 161         dest_stream, tmpfilename = sanitize_open(tmpfilename, open_mode)
 162
 163         ctx.update({
 164             'dl': dl,
 165             'dest_stream': dest_stream,
 166             'tmpfilename': tmpfilename,
 167             # Total complete fragments downloaded so far in bytes
 168             'complete_frags_downloaded_bytes': resume_len,
 169         })
 170
 171     def _start_frag_download(self, ctx):
 172         total_frags = ctx['total_frags']
 173         # This dict stores the download progress, it's updated by the progress
 174         # hook
 175         state = {
 176             'status': 'downloading',
 177             'downloaded_bytes': ctx['complete_frags_downloaded_bytes'],
 178             'fragment_index': ctx['fragment_index'],
 179             'fragment_count': total_frags,
 180             'filename': ctx['filename'],
 181             'tmpfilename': ctx['tmpfilename'],
 182         }
 183
 184         start = time.time()
 185         ctx.update({
 186             'started': start,
 187             # Amount of fragment's bytes downloaded by the time of the previous
 188             # frag progress hook invocation
 189             'prev_frag_downloaded_bytes': 0,
 190         })
 191
 192         def frag_progress_hook(s):
 193             if s['status'] not in ('downloading', 'finished'):
 194                 return
 195
 196             time_now = time.time()
 197             state['elapsed'] = time_now - start
 198             frag_total_bytes = s.get('total_bytes') or 0
 199             if not ctx['live']:
 200                 estimated_size = (
 201                     (ctx['complete_frags_downloaded_bytes'] + frag_total_bytes) /
 202                     (state['fragment_index'] + 1) * total_frags)
 203                 state['total_bytes_estimate'] = estimated_size
 204
 205             if s['status'] == 'finished':
 206                 state['fragment_index'] += 1
 207                 ctx['fragment_index'] = state['fragment_index']
 208                 state['downloaded_bytes'] += frag_total_bytes - ctx['prev_frag_downloaded_bytes']
 209                 ctx['complete_frags_downloaded_bytes'] = state['downloaded_bytes']
 210                 ctx['prev_frag_downloaded_bytes'] = 0
 211             else:
 212                 frag_downloaded_bytes = s['downloaded_bytes']
 213                 state['downloaded_bytes'] += frag_downloaded_bytes - ctx['prev_frag_downloaded_bytes']
 214                 if not ctx['live']:
 215                     state['eta'] = self.calc_eta(
 216                         start, time_now, estimated_size,
 217                         state['downloaded_bytes'])
 218                 state['speed'] = s.get('speed') or ctx.get('speed')
 219                 ctx['speed'] = state['speed']
 220                 ctx['prev_frag_downloaded_bytes'] = frag_downloaded_bytes
 221             self._hook_progress(state)
 222
 223         ctx['dl'].add_progress_hook(frag_progress_hook)
 224
 225         return start
 226
 227     def _finish_frag_download(self, ctx):
 228         ctx['dest_stream'].close()
 229         if self.__do_ytdl_file(ctx):
 230             ytdl_filename = encodeFilename(self.ytdl_filename(ctx['filename']))
 231             if os.path.isfile(ytdl_filename):
 232                 os.remove(ytdl_filename)
 233         elapsed = time.time() - ctx['started']
 234         self.try_rename(ctx['tmpfilename'], ctx['filename'])
 235         fsize = os.path.getsize(encodeFilename(ctx['filename']))
 236
 237         self._hook_progress({
 238             'downloaded_bytes': fsize,
 239             'total_bytes': fsize,
 240             'filename': ctx['filename'],
 241             'status': 'finished',
 242             'elapsed': elapsed,
 243         })