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

Code before:
        'playlist_mincount': 10,  # as of 2021/03/17
    }, {
        'url': 'https://www.nicovideo.jp/series/12312/',
        'info_dict': {
            'id': '12312',
            'title': 'バトルスピリッツ　お勧めカード紹介(調整中)',
        },
        'playlist_mincount': 97,  # as of 2021/03/17
    }, {
        'url': 'https://nico.ms/series/203559',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        list_id = self._match_id(url)
        webpage = self._download_webpage('https://www.nicovideo.jp/series/%s' % list_id, list_id)

        title = self._search_regex(
            (r'<title>「(.+)（全',
             r'<div class="TwitterShareButton"\s+data-text="(.+)\s+https:'),
            webpage, 'title', fatal=False)
        if title:
            title = unescapeHTML(title)
        playlist = []
        for match in re.finditer(r'href="/watch/([a-z0-9]+)" data-href="/watch/\1', webpage):
            playlist.append(self.url_result('https://www.nicovideo.jp/watch/%s' % match.group(1), video_id=match.group(1)))
        return self.playlist_result(playlist, list_id, title)


class NiconicoHistoryIE(NiconicoPlaylistBaseIE):
    IE_NAME = 'niconico:history'
    IE_DESC = 'NicoNico user history. Requires cookies.'
    # actual url of history page is "https://www.nicovideo.jp/my/history/video", but /video is omitted to widen matches
    _VALID_URL = r'https?://(?:www\.|sp\.)?nicovideo\.jp/my/history'

    _TESTS = [{
        'note': 'PC page, with /video',
        'url': 'https://www.nicovideo.jp/my/history/video',
        'only_matching': True,
    }, {
        'note': 'PC page, without /video',
        'url': 'https://www.nicovideo.jp/my/history',
        'only_matching': True,
    }, {
        'note': 'mobile page, with /video',
        'url': 'https://sp.nicovideo.jp/my/history/video',
        'only_matching': True,
    }, {
        'note': 'mobile page, without /video',
        'url': 'https://sp.nicovideo.jp/my/history',
        'only_matching': True,

Review comment (suggestion):
```suggestion
        for match in re.finditer(r'href="/watch/([a-z0-9]+)" data-href="/watch/\1', webpage):
            v_id = match.group(1)
            if not v_id:
                continue
            playlist.append(self.url_result(f'https://www.nicovideo.jp/watch/{v_id}', video_id=v_id))
```

Code after:
            'title': 'バトルスピリッツ　お勧めカード紹介(調整中)',
        },
        'playlist_mincount': 97,  # as of 2021/03/17
    }, {
        'url': 'https://nico.ms/series/203559',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        list_id = self._match_id(url)
        webpage = self._download_webpage(f'https://www.nicovideo.jp/series/{list_id}', list_id)

        title = self._search_regex(
            (r'<title>「(.+)（全',
             r'<div class="TwitterShareButton"\s+data-text="(.+)\s+https:'),
            webpage, 'title', fatal=False)
        if title:
            title = unescapeHTML(title)
        playlist = [
            self.url_result(f'https://www.nicovideo.jp/watch/{v_id}', video_id=v_id)
            for v_id in re.findall(r'href="/watch/([a-z0-9]+)" data-href="/watch/\1', webpage)]
        return self.playlist_result(playlist, list_id, title)


class NiconicoHistoryIE(NiconicoPlaylistBaseIE):
    IE_NAME = 'niconico:history'
    IE_DESC = 'NicoNico user history. Requires cookies.'
    _VALID_URL = r'https?://(?:www\.|sp\.)?nicovideo\.jp/my/history'

    _TESTS = [{
        'note': 'PC page, with /video',
        'url': 'https://www.nicovideo.jp/my/history/video',
        'only_matching': True,
    }, {
        'note': 'PC page, without /video',
        'url': 'https://www.nicovideo.jp/my/history',
        'only_matching': True,
    }, {
        'note': 'mobile page, with /video',
        'url': 'https://sp.nicovideo.jp/my/history/video',
        'only_matching': True,
    }, {
        'note': 'mobile page, without /video',
        'url': 'https://sp.nicovideo.jp/my/history',
        'only_matching': True,
    }]

    def _call_api(self, list_id, resource, query):
        return self._download_json(
            'https://nvapi.nicovideo.jp/v1/users/me/watch/history', 'history',
            f'Downloading {resource}', query=query,