[downloader/dash] Add fragment retry capability

YouTube may often return 404 HTTP error for a fragment causing the
whole download to fail. However if the same fragment is immediately
retried with the same request data this usually succeeds (1-2 attemps
is usually enough) thus allowing to download the whole file successfully.
So, we will retry all fragments that fail with 404 HTTP error for now.
This commit is contained in:
Sergey M․ 2016-03-19 20:42:23 +06:00
parent 721f26b821
commit e33baba0dd

View file

@ -4,6 +4,7 @@ import os
import re
from .fragment import FragmentFD
from ..compat import compat_urllib_error
from ..utils import (
sanitize_open,
encodeFilename,
@ -36,20 +37,41 @@ class DashSegmentsFD(FragmentFD):
segments_filenames = []
def append_url_to_file(target_url, target_filename):
success = ctx['dl'].download(target_filename, {'url': combine_url(base_url, target_url)})
if not success:
fragment_retries = self.params.get('fragment_retries', 0)
def append_url_to_file(target_url, tmp_filename, segment_name):
target_filename = '%s-%s' % (tmp_filename, segment_name)
count = 0
while count <= fragment_retries:
try:
success = ctx['dl'].download(target_filename, {'url': combine_url(base_url, target_url)})
if not success:
return False
down, target_sanitized = sanitize_open(target_filename, 'rb')
ctx['dest_stream'].write(down.read())
down.close()
segments_filenames.append(target_sanitized)
break
except (compat_urllib_error.HTTPError, ) as err:
# YouTube may often return 404 HTTP error for a fragment causing the
# whole download to fail. However if the same fragment is immediately
# retried with the same request data this usually succeeds (1-2 attemps
# is usually enough) thus allowing to download the whole file successfully.
# So, we will retry all fragments that fail with 404 HTTP error for now.
if err.code != 404:
raise
# Retry fragment
count += 1
if count <= fragment_retries:
self.report_retry_fragment(segment_name, count, fragment_retries)
if count > fragment_retries:
self.report_error('giving up after %s fragment retries' % fragment_retries)
return False
down, target_sanitized = sanitize_open(target_filename, 'rb')
ctx['dest_stream'].write(down.read())
down.close()
segments_filenames.append(target_sanitized)
if initialization_url:
append_url_to_file(initialization_url, ctx['tmpfilename'] + '-Init')
append_url_to_file(initialization_url, ctx['tmpfilename'], 'Init')
for i, segment_url in enumerate(segment_urls):
segment_filename = '%s-Seg%d' % (ctx['tmpfilename'], i)
append_url_to_file(segment_url, segment_filename)
append_url_to_file(segment_url, ctx['tmpfilename'], 'Seg%d' % i)
self._finish_frag_download(ctx)