[youtube:tab] Fallback to API when webpage fails to download (#1122)

and add some extractor_args to force this mode
Authored by: coletdjnz

README.md

@@ -1483,6 +1483,9 @@ # EXTRACTOR ARGUMENTS
     * `comment_sort`: `top` or `new` (default) - choose comment sorting mode (on YouTube's side).
     * `max_comments`: Maximum amount of comments to download (default all).
     * `max_comment_depth`: Maximum depth for nested comments. YouTube supports depths 1 or 2 (default).
+* **youtubetab**
+  (YouTube playlists, channels, feeds, etc.)
+   * `skip`: One or more of `webpage` (skip initial webpage download), `authcheck` (allow the download of playlists requiring authentication when no initial webpage is downloaded. This may cause unwanted behavior, see [#1122](https://github.com/yt-dlp/yt-dlp/pull/1122) for more details)
 
 * **funimation**
     * `language`: Languages to extract. Eg: `funimation:language=english,japanese`

yt_dlp/extractor/youtube.py

@@ -579,12 +579,12 @@ def _call_api(self, ep, query, video_id, fatal=True, headers=None,
             data=json.dumps(data).encode('utf8'), headers=real_headers,
             query={'key': api_key or self._extract_api_key()})
 
-    def extract_yt_initial_data(self, video_id, webpage):
+    def extract_yt_initial_data(self, item_id, webpage, fatal=True):
-        return self._parse_json(
+        data = self._search_regex(
-            self._search_regex(
             (r'%s\s*%s' % (self._YT_INITIAL_DATA_RE, self._YT_INITIAL_BOUNDARY_RE),
-                 self._YT_INITIAL_DATA_RE), webpage, 'yt initial data'),
+             self._YT_INITIAL_DATA_RE), webpage, 'yt initial data', fatal=fatal)
-            video_id)
+        if data:
+            return self._parse_json(data, item_id, fatal=fatal)
 
     @staticmethod
     def _extract_session_index(*data):
@@ -627,6 +627,16 @@ def _extract_account_syncid(*args):
                 # and just "user_syncid||" for primary channel. We only want the channel_syncid
                 return sync_ids[0]
 
+    @staticmethod
+    def _extract_visitor_data(*args):
+        """
+        Extracts visitorData from an API response or ytcfg
+        Appears to be used to track session state
+        """
+        return traverse_obj(
+            args, (..., ('VISITOR_DATA', ('INNERTUBE_CONTEXT', 'client', 'visitorData'), ('responseContext', 'visitorData'))),
+            expected_type=compat_str, get_all=False)
+
     @property
     def is_authenticated(self):
         return bool(self._generate_sapisidhash_header())
@@ -651,8 +661,7 @@ def generate_api_headers(
             'Origin': origin,
             'X-Youtube-Identity-Token': identity_token or self._extract_identity_token(ytcfg),
             'X-Goog-PageId': account_syncid or self._extract_account_syncid(ytcfg),
-            'X-Goog-Visitor-Id': visitor_data or try_get(
+            'X-Goog-Visitor-Id': visitor_data or self._extract_visitor_data(ytcfg)
-                self._extract_context(ytcfg, default_client), lambda x: x['client']['visitorData'], compat_str)
         }
         if session_index is None:
             session_index = self._extract_session_index(ytcfg)
@@ -826,9 +835,8 @@ def _extract_response(self, item_id, query, note='Downloading API JSON', headers
                     return
 
             else:
-                # Youtube may send alerts if there was an issue with the continuation page
                 try:
-                    self._extract_and_report_alerts(response, expected=False, only_once=True)
+                    self._extract_and_report_alerts(response, only_once=True)
                 except ExtractorError as e:
                     # YouTube servers may return errors we want to retry on in a 200 OK response
                     # See: https://github.com/yt-dlp/yt-dlp/issues/839
@@ -3549,7 +3557,7 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
         'url': 'https://www.youtube.com/feed/watch_later',
         'only_matching': True,
     }, {
-        'note': 'Recommended - redirects to home page',
+        'note': 'Recommended - redirects to home page.',
         'url': 'https://www.youtube.com/feed/recommended',
         'only_matching': True,
     }, {
@@ -3646,6 +3654,51 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
             'availability': 'unlisted'
         },
         'playlist_count': 1,
+    }, {
+        'note': 'API Fallback: Recommended - redirects to home page. Requires visitorData',
+        'url': 'https://www.youtube.com/feed/recommended',
+        'info_dict': {
+            'id': 'recommended',
+            'title': 'recommended',
+        },
+        'playlist_mincount': 50,
+        'params': {
+            'skip_download': True,
+            'extractor_args': {'youtubetab': {'skip': ['webpage']}}
+        },
+    }, {
+        'note': 'API Fallback: /videos tab, sorted by oldest first',
+        'url': 'https://www.youtube.com/user/theCodyReeder/videos?view=0&sort=da&flow=grid',
+        'info_dict': {
+            'id': 'UCu6mSoMNzHQiBIOCkHUa2Aw',
+            'title': 'Cody\'sLab - Videos',
+            'description': 'md5:d083b7c2f0c67ee7a6c74c3e9b4243fa',
+            'uploader': 'Cody\'sLab',
+            'uploader_id': 'UCu6mSoMNzHQiBIOCkHUa2Aw',
+        },
+        'playlist_mincount': 650,
+        'params': {
+            'skip_download': True,
+            'extractor_args': {'youtubetab': {'skip': ['webpage']}}
+        },
+    }, {
+        'note': 'API Fallback: Topic, should redirect to playlist?list=UU...',
+        'url': 'https://music.youtube.com/browse/UC9ALqqC4aIeG5iDs7i90Bfw',
+        'info_dict': {
+            'id': 'UU9ALqqC4aIeG5iDs7i90Bfw',
+            'uploader_id': 'UC9ALqqC4aIeG5iDs7i90Bfw',
+            'title': 'Uploads from Royalty Free Music - Topic',
+            'uploader': 'Royalty Free Music - Topic',
+        },
+        'expected_warnings': [
+            'A channel/user page was given',
+            'The URL does not have a videos tab',
+        ],
+        'playlist_mincount': 101,
+        'params': {
+            'skip_download': True,
+            'extractor_args': {'youtubetab': {'skip': ['webpage']}}
+        },
     }]
 
     @classmethod
@@ -3834,7 +3887,7 @@ def _rich_grid_entries(self, contents):
                 if entry:
                     yield entry
     '''
-    def _entries(self, tab, item_id, account_syncid, ytcfg):
+    def _entries(self, tab, item_id, ytcfg, account_syncid, visitor_data):
 
         def extract_entries(parent_renderer):  # this needs to called again for continuation to work with feeds
             contents = try_get(parent_renderer, lambda x: x['contents'], list) or []
@@ -3886,7 +3939,6 @@ def extract_entries(parent_renderer):  # this needs to called again for continua
         for entry in extract_entries(parent_renderer):
             yield entry
         continuation = continuation_list[0]
-        visitor_data = None
 
         for page_num in itertools.count(1):
             if not continuation:
@@ -3900,8 +3952,9 @@ def extract_entries(parent_renderer):  # this needs to called again for continua
 
             if not response:
                 break
-            visitor_data = try_get(
+            # Extracting updated visitor data is required to prevent an infinite extraction loop in some cases
-                response, lambda x: x['responseContext']['visitorData'], compat_str) or visitor_data
+            # See: https://github.com/ytdl-org/youtube-dl/issues/28702
+            visitor_data = self._extract_visitor_data(response) or visitor_data
 
             known_continuation_renderers = {
                 'playlistVideoListContinuation': self._playlist_entries,
@@ -3975,9 +4028,10 @@ def _extract_uploader(cls, data):
                 try_get(owner, lambda x: x['navigationEndpoint']['browseEndpoint']['canonicalBaseUrl'], compat_str))
         return {k: v for k, v in uploader.items() if v is not None}
 
-    def _extract_from_tabs(self, item_id, webpage, data, tabs):
+    def _extract_from_tabs(self, item_id, ytcfg, data, tabs):
         playlist_id = title = description = channel_url = channel_name = channel_id = None
-        thumbnails_list = tags = []
+        thumbnails_list = []
+        tags = []
 
         selected_tab = self._extract_selected_tab(tabs)
         renderer = try_get(
@@ -4042,18 +4096,15 @@ def _extract_from_tabs(self, item_id, webpage, data, tabs):
             'channel': metadata['uploader'],
             'channel_id': metadata['uploader_id'],
             'channel_url': metadata['uploader_url']})
-        ytcfg = self.extract_ytcfg(item_id, webpage)
         return self.playlist_result(
             self._entries(
-                selected_tab, playlist_id,
+                selected_tab, playlist_id, ytcfg,
-                self._extract_account_syncid(ytcfg, data), ytcfg),
+                self._extract_account_syncid(ytcfg, data),
+                self._extract_visitor_data(data, ytcfg)),
             **metadata)
 
-    def _extract_mix_playlist(self, playlist, playlist_id, data, webpage):
+    def _extract_mix_playlist(self, playlist, playlist_id, data, ytcfg):
-        first_id = last_id = None
+        first_id = last_id = response = None
-        ytcfg = self.extract_ytcfg(playlist_id, webpage)
-        headers = self.generate_api_headers(
-            ytcfg=ytcfg, account_syncid=self._extract_account_syncid(ytcfg, data))
         for page_num in itertools.count(1):
             videos = list(self._playlist_entries(playlist))
             if not videos:
@@ -4070,6 +4121,9 @@ def _extract_mix_playlist(self, playlist, playlist_id, data, webpage):
             last_id = videos[-1]['id']
             watch_endpoint = try_get(
                 playlist, lambda x: x['contents'][-1]['playlistPanelVideoRenderer']['navigationEndpoint']['watchEndpoint'])
+            headers = self.generate_api_headers(
+                ytcfg=ytcfg, account_syncid=self._extract_account_syncid(ytcfg, data),
+                visitor_data=self._extract_visitor_data(response, data, ytcfg))
             query = {
                 'playlistId': playlist_id,
                 'videoId': watch_endpoint.get('videoId') or last_id,
@@ -4084,7 +4138,7 @@ def _extract_mix_playlist(self, playlist, playlist_id, data, webpage):
             playlist = try_get(
                 response, lambda x: x['contents']['twoColumnWatchNextResults']['playlist']['playlist'], dict)
 
-    def _extract_from_playlist(self, item_id, url, data, playlist, webpage):
+    def _extract_from_playlist(self, item_id, url, data, playlist, ytcfg):
         title = playlist.get('title') or try_get(
             data, lambda x: x['titleText']['simpleText'], compat_str)
         playlist_id = playlist.get('playlistId') or item_id
@@ -4099,7 +4153,7 @@ def _extract_from_playlist(self, item_id, url, data, playlist, webpage):
                 video_title=title)
 
         return self.playlist_result(
-            self._extract_mix_playlist(playlist, playlist_id, data, webpage),
+            self._extract_mix_playlist(playlist, playlist_id, data, ytcfg),
             playlist_id=playlist_id, playlist_title=title)
 
     def _extract_availability(self, data):
@@ -4143,7 +4197,7 @@ def _extract_sidebar_info_renderer(data, info_renderer, expected_type=dict):
             if renderer:
                 return renderer
 
-    def _reload_with_unavailable_videos(self, item_id, data, webpage):
+    def _reload_with_unavailable_videos(self, item_id, data, ytcfg):
         """
         Get playlist with unavailable videos if the 'show unavailable videos' button exists.
         """
@@ -4167,10 +4221,9 @@ def _reload_with_unavailable_videos(self, item_id, data, webpage):
             params = browse_endpoint.get('params')
             break
 
-        ytcfg = self.extract_ytcfg(item_id, webpage)
         headers = self.generate_api_headers(
             ytcfg=ytcfg, account_syncid=self._extract_account_syncid(ytcfg, data),
-            visitor_data=try_get(self._extract_context(ytcfg), lambda x: x['client']['visitorData'], compat_str))
+            visitor_data=self._extract_visitor_data(data, ytcfg))
         query = {
             'params': params or 'wgYCCAA=',
             'browseId': browse_id or 'VL%s' % item_id
@@ -4180,28 +4233,87 @@ def _reload_with_unavailable_videos(self, item_id, data, webpage):
             check_get_keys='contents', fatal=False, ytcfg=ytcfg,
             note='Downloading API JSON with unavailable videos')
 
-    def _extract_webpage(self, url, item_id):
+    def _extract_webpage(self, url, item_id, fatal=True):
         retries = self.get_param('extractor_retries', 3)
         count = -1
-        last_error = 'Incomplete yt initial data recieved'
+        webpage = data = last_error = None
         while count < retries:
             count += 1
             # Sometimes youtube returns a webpage with incomplete ytInitialData
             # See: https://github.com/yt-dlp/yt-dlp/issues/116
-            if count:
+            if last_error:
                 self.report_warning('%s. Retrying ...' % last_error)
+            try:
                 webpage = self._download_webpage(
                     url, item_id,
-                'Downloading webpage%s' % (' (retry #%d)' % count if count else ''))
+                    note='Downloading webpage%s' % (' (retry #%d)' % count if count else '',))
-            data = self.extract_yt_initial_data(item_id, webpage)
+                data = self.extract_yt_initial_data(item_id, webpage or '', fatal=fatal) or {}
-            if data.get('contents') or data.get('currentVideoEndpoint'):
+            except ExtractorError as e:
+                if isinstance(e.cause, network_exceptions):
+                    if not isinstance(e.cause, compat_HTTPError) or e.cause.code not in (403, 429):
+                        last_error = error_to_compat_str(e.cause or e.msg)
+                        if count < retries:
+                            continue
+                if fatal:
+                    raise
+                self.report_warning(error_to_compat_str(e))
                 break
-            # Extract alerts here only when there is error
+            else:
+                try:
                     self._extract_and_report_alerts(data)
+                except ExtractorError as e:
+                    if fatal:
+                        raise
+                    self.report_warning(error_to_compat_str(e))
+                    break
+
+                if dict_get(data, ('contents', 'currentVideoEndpoint')):
+                    break
+
+                last_error = 'Incomplete yt initial data received'
                 if count >= retries:
+                    if fatal:
                         raise ExtractorError(last_error)
+                    self.report_warning(last_error)
+                    break
+
         return webpage, data
 
+    def _extract_data(self, url, item_id, ytcfg=None, fatal=True, webpage_fatal=False, default_client='web'):
+        data = None
+        if 'webpage' not in self._configuration_arg('skip'):
+            webpage, data = self._extract_webpage(url, item_id, fatal=webpage_fatal)
+            ytcfg = ytcfg or self.extract_ytcfg(item_id, webpage)
+        if not data:
+            if not ytcfg and self.is_authenticated:
+                msg = 'Playlists that require authentication may not extract correctly without a successful webpage download.'
+                if 'authcheck' not in self._configuration_arg('skip') and fatal:
+                    raise ExtractorError(
+                        msg + ' If you are not downloading private content, or your cookies are only for the first account and channel,'
+                              ' pass "--extractor-args youtubetab:skip=authcheck" to skip this check',
+                        expected=True)
+                self.report_warning(msg, only_once=True)
+            data = self._extract_tab_endpoint(url, item_id, ytcfg, fatal=fatal, default_client=default_client)
+        return data, ytcfg
+
+    def _extract_tab_endpoint(self, url, item_id, ytcfg=None, fatal=True, default_client='web'):
+        headers = self.generate_api_headers(ytcfg=ytcfg, default_client=default_client)
+        resolve_response = self._extract_response(
+            item_id=item_id, query={'url': url}, check_get_keys='endpoint', headers=headers, ytcfg=ytcfg, fatal=fatal,
+            ep='navigation/resolve_url', note='Downloading API parameters API JSON', default_client=default_client)
+        endpoints = {'browseEndpoint': 'browse', 'watchEndpoint': 'next'}
+        for ep_key, ep in endpoints.items():
+            params = try_get(resolve_response, lambda x: x['endpoint'][ep_key], dict)
+            if params:
+                return self._extract_response(
+                    item_id=item_id, query=params, ep=ep, headers=headers,
+                    ytcfg=ytcfg, fatal=fatal, default_client=default_client,
+                    check_get_keys=('contents', 'currentVideoEndpoint'))
+        err_note = 'Failed to resolve url (does the playlist exist?)'
+        if fatal:
+            raise ExtractorError(err_note, expected=True)
+        self.report_warning(err_note, item_id)
+
     @staticmethod
     def _smuggle_data(entries, data):
         for entry in entries:
@@ -4234,7 +4346,6 @@ def get_mobj(url):
         mobj = get_mobj(url)
         # Youtube returns incomplete data if tabname is not lower case
         pre, tab, post, is_channel = mobj['pre'], mobj['tab'].lower(), mobj['post'], not mobj['not_channel']
-
         if is_channel:
             if smuggled_data.get('is_music_url'):
                 if item_id[:2] == 'VL':
@@ -4242,12 +4353,14 @@ def get_mobj(url):
                     item_id = item_id[2:]
                     pre, tab, post, is_channel = 'https://www.youtube.com/playlist?list=%s' % item_id, '', '', False
                 elif item_id[:2] == 'MP':
-                    # Youtube music albums (/channel/MP...) have a OLAK playlist that can be extracted from the webpage
+                    # Resolve albums (/[channel/browse]/MP...) to their equivalent playlist
-                    item_id = self._search_regex(
+                    mdata = self._extract_tab_endpoint(
-                        r'\\x22audioPlaylistId\\x22:\\x22([0-9A-Za-z_-]+)\\x22',
+                        'https://music.youtube.com/channel/%s' % item_id, item_id, default_client='web_music')
-                        self._download_webpage('https://music.youtube.com/channel/%s' % item_id, item_id),
+                    murl = traverse_obj(
-                        'playlist id')
+                        mdata, ('microformat', 'microformatDataRenderer', 'urlCanonical'), get_all=False, expected_type=compat_str)
-                    pre, tab, post, is_channel = 'https://www.youtube.com/playlist?list=%s' % item_id, '', '', False
+                    if not murl:
+                        raise ExtractorError('Failed to resolve album to playlist.')
+                    return self.url_result(murl, ie=YoutubeTabIE.ie_key())
                 elif mobj['channel_type'] == 'browse':
                     # Youtube music /browse/ should be changed to /channel/
                     pre = 'https://www.youtube.com/channel/%s' % item_id
@@ -4281,7 +4394,7 @@ def get_mobj(url):
                 return self.url_result(f'https://www.youtube.com/watch?v={video_id}', ie=YoutubeIE.ie_key(), video_id=video_id)
             self.to_screen('Downloading playlist %s; add --no-playlist to just download video %s' % (playlist_id, video_id))
 
-        webpage, data = self._extract_webpage(url, item_id)
+        data, ytcfg = self._extract_data(url, item_id)
 
         tabs = try_get(
             data, lambda x: x['contents']['twoColumnBrowseResultsRenderer']['tabs'], list)
@@ -4299,11 +4412,7 @@ def get_mobj(url):
                         pl_id = 'UU%s' % item_id[2:]
                         pl_url = 'https://www.youtube.com/playlist?list=%s%s' % (pl_id, mobj['post'])
                         try:
-                            pl_webpage, pl_data = self._extract_webpage(pl_url, pl_id)
+                            data, ytcfg, item_id, url = *self._extract_data(pl_url, pl_id, ytcfg=ytcfg, fatal=True), pl_id, pl_url
-                            for alert_type, alert_message in self._extract_alerts(pl_data):
-                                if alert_type == 'error':
-                                    raise ExtractorError('Youtube said: %s' % alert_message)
-                            item_id, url, webpage, data = pl_id, pl_url, pl_webpage, pl_data
                         except ExtractorError:
                             self.report_warning('The playlist gave error. Falling back to channel URL')
                     else:
@@ -4313,17 +4422,17 @@ def get_mobj(url):
 
         # YouTube sometimes provides a button to reload playlist with unavailable videos.
         if 'no-youtube-unavailable-videos' not in compat_opts:
-            data = self._reload_with_unavailable_videos(item_id, data, webpage) or data
+            data = self._reload_with_unavailable_videos(item_id, data, ytcfg) or data
         self._extract_and_report_alerts(data, only_once=True)
         tabs = try_get(
             data, lambda x: x['contents']['twoColumnBrowseResultsRenderer']['tabs'], list)
         if tabs:
-            return self._extract_from_tabs(item_id, webpage, data, tabs)
+            return self._extract_from_tabs(item_id, ytcfg, data, tabs)
 
         playlist = try_get(
             data, lambda x: x['contents']['twoColumnWatchNextResults']['playlist']['playlist'], dict)
         if playlist:
-            return self._extract_from_playlist(item_id, url, data, playlist, webpage)
+            return self._extract_from_playlist(item_id, url, data, playlist, ytcfg)
 
         video_id = try_get(
             data, lambda x: x['currentVideoEndpoint']['watchEndpoint']['videoId'],