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[teamcoco] Rewrite preload data extraction

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Idea: "puncture" some consecutive fragments and check whether the
b64decode result of a punctured string is a valid JSON or not.

It's a O(N^3) algorithm, but should be fast for a small N (less than 30
fragments in all test cases)
This commit is contained in:
Yen Chi Hsuan 2015-05-15 02:17:22 +08:00
parent 1ae72fb23d
commit 3a105f7b20
1 changed files with 26 additions and 27 deletions
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45
youtube_dl/extractor/teamcoco.py
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@ -4,6 +4,7 @@
import base64
import binascii
import re
import json
from .common import InfoExtractor
from ..utils import (
@ -68,41 +69,39 @@ def _real_extract(self, url):
video_id = self._html_search_regex(
self._VIDEO_ID_REGEXES, webpage, 'video id')
data = preload = None
preloads = re.findall(r'"preload":\s*"([^"]+)"', webpage)
if preloads:
preload = max([(len(p), p) for p in preloads])[1]
data = None
if not preload:
preload = ''.join(re.findall(r'this\.push\("([^"]+)"\);', webpage))
if not preload:
preload = self._html_search_regex([
r'player,\[?"([^"]+)"\]?', r'player.init\(\[?"([^"]+)"\]?\)'
], webpage.replace('","', ''), 'preload data', default=None)
if not preload:
preload_codes = self._html_search_regex(
r'(function.+)setTimeout\(function\(\)\{playlist',
webpage, 'preload codes')
base64_fragments = re.findall(r'"([a-zA-z0-9+/=]+)"', preload_codes)
base64_fragments.remove('init')
for i in range(len(base64_fragments)):
cur_sequence = (''.join(base64_fragments[i:] + base64_fragments[:i])).encode('ascii')
def _check_sequence(cur_fragments):
if not cur_fragments:
return
for i in range(len(cur_fragments)):
cur_sequence = (''.join(cur_fragments[i:] + cur_fragments[:i])).encode('ascii')
try:
raw_data = base64.b64decode(cur_sequence)
except (TypeError, binascii.Error):
continue
if compat_ord(raw_data[0]) == compat_ord('{'):
data = self._parse_json(raw_data.decode('utf-8'), video_id, fatal=False)
return json.loads(raw_data.decode('utf-8'))
except (TypeError, binascii.Error, UnicodeDecodeError, ValueError):
continue
if not preload and not data:
raise ExtractorError(
'Preload information could not be extracted', expected=True)
def _check_data():
for i in range(len(base64_fragments) + 1):
for j in range(i, len(base64_fragments) + 1):
data = _check_sequence(base64_fragments[:i] + base64_fragments[j:])
if data:
return data
self.to_screen('Try to compute possible data sequence. This may take some time.')
data = _check_data()
if not data:
data = self._parse_json(
base64.b64decode(preload.encode('ascii')).decode('utf-8'), video_id)
raise ExtractorError(
'Preload information could not be extracted', expected=True)
formats = []
get_quality = qualities(['500k', '480p', '1000k', '720p', '1080p'])