Always extract original URL from next_url (#318)

Author: FiloSottile

youtube-dl

@@ -1171,12 +1171,11 @@ class InfoExtractor(object):
 class YoutubeIE(InfoExtractor):
 	"""Information extractor for youtube.com."""
 
-	_PREFIX = r'(?:https?://)?(?:youtu\.be/|(?:\w+\.)?youtube(?:-nocookie)?\.com/)'
-	_VALID_URL = r'^('+_PREFIX+r'(?!view_play_list|my_playlists|artist|playlist)(?:(?:(?:v|embed|e)/)|(?:(?:watch(?:_popup)?(?:\.php)?)?(?:\?|#!?)(?:.+&)?v=))?)?([0-9A-Za-z_-]+)(?(1).+)?$'
-	_VALID_URL_WITH_AGE = r'^('+_PREFIX+')verify_age\?next_url=([^&]+)(?:.+)?$'
+	_VALID_URL = r'^((?:https?://)?(?:youtu\.be/|(?:\w+\.)?youtube(?:-nocookie)?\.com/)(?!view_play_list|my_playlists|artist|playlist)(?:(?:(?:v|embed|e)/)|(?:(?:watch(?:_popup)?(?:\.php)?)?(?:\?|#!?)(?:.+&)?v=))?)?([0-9A-Za-z_-]+)(?(1).+)?$'
 	_LANG_URL = r'http://www.youtube.com/?hl=en&persist_hl=1&gl=US&persist_gl=1&opt_out_ackd=1'
 	_LOGIN_URL = 'https://www.youtube.com/signup?next=/&gl=US&hl=en'
 	_AGE_URL = 'http://www.youtube.com/verify_age?next_url=/&gl=US&hl=en'
+	_NEXT_URL_RE = r'[\?&]next_url=([^&]+)'
 	_NETRC_MACHINE = 'youtube'
 	# Listed in order of quality
 	_available_formats = ['38', '37', '22', '45', '35', '44', '34', '18', '43', '6', '5', '17', '13']
@@ -1337,13 +1336,10 @@ class YoutubeIE(InfoExtractor):
 			return
 
 	def _real_extract(self, url):
-		# Extract original video URL from URL with age verification, using next_url parameter
-		mobj = re.match(self._VALID_URL_WITH_AGE, url)
+		# Extract original video URL from URL with redirection, like age verification, using next_url parameter
+		mobj = re.search(self._NEXT_URL_RE, url)
 		if mobj:
-			urldecode = lambda x: re.sub(r'%([0-9a-hA-H][0-9a-hA-H])', lambda m: chr(int(m.group(1), 16)), x)
-			# Keep original domain. We can probably change to www.youtube.com, but it should not hurt so keep it.
-			# We just make sure we do not have double //, in URL, so we strip starting slash in next_url.
-			url = mobj.group(1) + re.sub(r'^/', '', urldecode(mobj.group(2)))
+			url = 'http://www.youtube.com/' + urllib.unquote(mobj.group(1)).lstrip('/')
 
 		# Extract video id from URL
 		mobj = re.match(self._VALID_URL, url)