[twitcasting] Add fallback for finding running live (#2803)

Authored by: Lesmiscore

yt_dlp/extractor/twitcasting.py

@@ -220,6 +220,17 @@ class TwitCastingLiveIE(InfoExtractor):
             (r'data-type="movie" data-id="(\d+)">',
              r'tw-sound-flag-open-link" data-id="(\d+)" style=',),
             webpage, 'current live ID', default=None)
+        if not current_live:
+            # fetch unfiltered /show to find running livestreams; we can't get ID of the password-protected livestream above
+            webpage = self._download_webpage(
+                f'https://twitcasting.tv/{uploader_id}/show/', uploader_id,
+                note='Downloading live history')
+            is_live = self._search_regex(r'(?s)(<span\s*class="tw-movie-thumbnail-badge"\s*data-status="live">\s*LIVE)', webpage, 'is live?', default=None)
+            if is_live:
+                # get the first live; running live is always at the first
+                current_live = self._search_regex(
+                    r'(?s)<a\s+class="tw-movie-thumbnail"\s*href="/[^/]+/movie/(?P<video_id>\d+)"\s*>.+?</a>',
+                    webpage, 'current live ID 2', default=None, group='video_id')
         if not current_live:
             raise ExtractorError('The user is not currently live')
         return self.url_result('https://twitcasting.tv/%s/movie/%s' % (uploader_id, current_live))