[roosterteeth.com] Add subtitle support (https://github.com/ytdl-org/youtube-dl/pull/23985)

Closes #15

Authored by samiksome

youtube_dlc/extractor/roosterteeth.py

@@ -86,9 +86,11 @@ class RoosterTeethIE(InfoExtractor):
         api_episode_url = self._EPISODE_BASE_URL + display_id
 
         try:
-            m3u8_url = self._download_json(
+            video_data = self._download_json(
                 api_episode_url + '/videos', display_id,
-                'Downloading video JSON metadata')['data'][0]['attributes']['url']
+                'Downloading video JSON metadata')['data'][0]
+            m3u8_url = video_data['attributes']['url']
+            subtitle_m3u8_url = video_data['links']['download']
         except ExtractorError as e:
             if isinstance(e.cause, compat_HTTPError) and e.cause.code == 403:
                 if self._parse_json(e.cause.read().decode(), display_id).get('access') is False:
@@ -119,6 +121,33 @@ class RoosterTeethIE(InfoExtractor):
                             'url': img_url,
                         })
 
+        subtitles = {}
+        res = self._download_webpage_handle(
+            subtitle_m3u8_url, display_id,
+            'Downloading m3u8 information',
+            'Failed to download m3u8 information',
+            fatal=True, data=None, headers={}, query={})
+        if res is not False:
+            subtitle_m3u8_doc, _ = res
+            for line in subtitle_m3u8_doc.split('\n'):
+                if 'EXT-X-MEDIA:TYPE=SUBTITLES' in line:
+                    parts = line.split(',')
+                    for part in parts:
+                        if 'LANGUAGE' in part:
+                            lang = part[part.index('=') + 2:-1]
+                        elif 'URI' in part:
+                            uri = part[part.index('=') + 2:-1]
+                    res = self._download_webpage_handle(
+                        uri, display_id,
+                        'Downloading m3u8 information',
+                        'Failed to download m3u8 information',
+                        fatal=True, data=None, headers={}, query={})
+                    doc, _ = res
+                    for l in doc.split('\n'):
+                        if not l.startswith('#'):
+                            subtitles[lang] = [{'url': uri[:-uri[::-1].index('/')] + l}]
+                            break
+
         return {
             'id': video_id,
             'display_id': display_id,
@@ -134,4 +163,5 @@ class RoosterTeethIE(InfoExtractor):
             'formats': formats,
             'channel_id': attributes.get('channel_id'),
             'duration': int_or_none(attributes.get('length')),
+            'subtitles': subtitles
         }