Repository: yt-dlp/yt-dlp
File: yt_dlp/extractor/saitosan.py (Python)

Code before:
        'params': {
            # m3u8 download
            'skip_download': True,
        },
        'skip': 'Broadcasts are ephemeral',
    }]

    def _real_extract(self, url):
        b_id = self._match_id(url)

        def format_socket_response_as_json(data):
            return self._parse_json(data[data.find('{'):data.rfind('}') + 1], b_id)

        base = 'http://hankachi.saitosan-api.net:8002/socket.io/?transport=polling&EIO=3'
        sid = format_socket_response_as_json(self._download_webpage(base, b_id, note='Opening socket')).get('sid')
        base += "&sid=" + sid

        self._download_webpage(base, b_id, note="Polling socket")
        payload = '420["room_start_join",{"room_id":"' + str(b_id) + '"}]'
        payload = str(len(payload)) + ":" + payload

        self._download_webpage(base, b_id, data=payload, note="Polling socket")
        should_continue = format_socket_response_as_json(self._download_webpage(base, b_id, note="Polling socket")).get('ok')
        if not should_continue:
            # The socket does not give any specific error messages.
            self.raise_no_formats("The socket reported that the broadcast could not be joined. Maybe it's offline or the URL is incorrect", expected=True)

        self._download_webpage(base, b_id, data='26:421["room_finish_join",{}]', note="Polling socket")
        b_data = format_socket_response_as_json(self._download_webpage(base, b_id, note='Getting broadcast metadata from socket'))

        self._download_webpage(base, b_id, data="1:1", note="Closing socket")

        title = b_data.get('name')
        uploader = b_data.get('broadcast_user')
        uploader_name = uploader.get('name')  # same as title

        m3u8_url = b_data.get('url')
        thumbnail = m3u8_url.replace('av.m3u8', 'thumb')
        formats = self._extract_m3u8_formats(m3u8_url, b_id, 'mp4', live=True)

        return {
            'id': b_id,
            'title': title,
            'formats': formats,
            'thumbnail': thumbnail,
            'uploader': uploader_name,
            'is_live': True
        }


Review comment (bug):
```suggestion
            raise ExtractorError(
                'The socket reported that the broadcast could not be joined. Maybe it's offline or the URL is incorrect',
                expected=True, video_id=b_id)
```
`raise_no_formats` is for when metadata is available, but download links are not

Code after:
            'is_live': True,
        },
        'params': {
            # m3u8 download
            'skip_download': True,
        },
        'skip': 'Broadcasts are ephemeral',
    }]

    def _real_extract(self, url):
        b_id = self._match_id(url)

        base = 'http://hankachi.saitosan-api.net:8002/socket.io/?transport=polling&EIO=3'
        sid = self._download_socket_json(base, b_id, note='Opening socket').get('sid')
        base += '&sid=' + sid

        self._download_webpage(base, b_id, note='Polling socket')
        payload = '420["room_start_join",{"room_id":"%s"}]' % b_id
        payload = '%s:%s' % (len(payload), payload)

        self._download_webpage(base, b_id, data=payload, note='Polling socket with payload')
        response = self._download_socket_json(base, b_id, note='Polling socket')
        if not response.get('ok'):
            err = response.get('error') or {}
            raise ExtractorError(
                '%s said: %s - %s' % (self.IE_NAME, err.get('code', '?'), err.get('msg', 'Unknown')) if err
                else 'The socket reported that the broadcast could not be joined. Maybe it\'s offline or the URL is incorrect',
                expected=True, video_id=b_id)

        self._download_webpage(base, b_id, data='26:421["room_finish_join",{}]', note='Polling socket')
        b_data = self._download_socket_json(base, b_id, note='Getting broadcast metadata from socket')
        m3u8_url = b_data.get('url')

        self._download_webpage(base, b_id, data='1:1', note='Closing socket', fatal=False)

        return {
            'id': b_id,
            'title': b_data.get('name'),
            'formats': self._extract_m3u8_formats(m3u8_url, b_id, 'mp4', live=True),
            'thumbnail': m3u8_url.replace('av.m3u8', 'thumb'),
            'uploader': try_get(b_data, lambda x: x['broadcast_user']['name']),  # same as title
            'is_live': True
        }