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

Code before:
class XiaoHongShuIE(InfoExtractor):
    _VALID_URL = r'https?://www\.xiaohongshu.com/explore/(?P<id>[a-f0-9]+)'
    IE_DESC = '小红书'
    _TESTS = [{
        'url': 'https://www.xiaohongshu.com/explore/6411cf99000000001300b6d9',
        'md5': '2a87a77ddbedcaeeda8d7eae61b61228',
        'info_dict': {
            'id': '6411cf99000000001300b6d9',
            'ext': 'mp4',
            'uploader_id': '5c31698d0000000007018a31',
            'description': '#今日快乐今日发[话题]# #吃货薯看这里[话题]# #香妃蛋糕[话题]# #小五卷蛋糕[话题]# #新手蛋糕卷[话题]#',
            'title': '香妃蛋糕也太香了吧🔥不需要卷❗️绝对的友好',
            'tags': ['今日快乐今日发', '吃货薯看这里', '香妃蛋糕', '小五卷蛋糕', '新手蛋糕卷'],
            'duration': 101.726,
            'thumbnail': r're:https?://sns-webpic-qc\.xhscdn\.com/\d+/[a-z0-9]+/[\w]+',
        }
    }]

    def _real_extract(self, url):
        display_id = self._match_id(url)
        webpage = self._download_webpage(url, display_id)
        initial_state = self._search_json(
            r'window\.__INITIAL_STATE__\s*=', webpage, 'initial state', display_id, transform_source=js_to_json)

        note_info = traverse_obj(initial_state, ('note', 'noteDetailMap', display_id, 'note'))
        video_info = traverse_obj(note_info, ('video', 'media', 'stream', ('h264', 'av1', 'h265'), ...))

        formats = []
        for info in video_info:
            format_info = traverse_obj(info, {
                'fps': 'fps',
                'width': 'width',
                'height': 'height',
                'vcodec': 'videoCodec',
                'acodec': 'audioCodec',
                'abr': 'audioBitrate',
                'vbr': 'videoBitrate',
                'audio_channels': 'audioChannels',
                'tbr': 'avgBitrate',
                'format': 'qualityType',
                'filesize': 'size',
                'duration': ('duration', {lambda x: float_or_none(x, scale=1000)})
            })

            formats.extend(traverse_obj(info, (('mediaUrl', ('backupUrls', ...)), {
                lambda url: url_or_none(url) and {'url': url, 'ext': 'mp4', **format_info}})))

        thumbnails = []
        for image_info in traverse_obj(note_info, ('imageList', ...)):
            thumbnail_info = traverse_obj(image_info, {
                'height': 'height',

Review comment (bug):
This fails regularly for me with a captcha being served. 

While using their API at `https://edith.xiaohongshu.com/api/sns/web/v1/feed` would be nice, it seems like we need to calculate some signature parameters for that. Doesn't look too complicated, but I don't think it needs to be done as part of this PR.

Code after:
from ..utils.traversal import traverse_obj


class XiaoHongShuIE(InfoExtractor):
    _VALID_URL = r'https?://www\.xiaohongshu\.com/explore/(?P<id>[\da-f]+)'
    IE_DESC = '小红书'
    _TESTS = [{
        'url': 'https://www.xiaohongshu.com/explore/6411cf99000000001300b6d9',
        'md5': '2a87a77ddbedcaeeda8d7eae61b61228',
        'info_dict': {
            'id': '6411cf99000000001300b6d9',
            'ext': 'mp4',
            'uploader_id': '5c31698d0000000007018a31',
            'description': '#今日快乐今日发[话题]# #吃货薯看这里[话题]# #香妃蛋糕[话题]# #小五卷蛋糕[话题]# #新手蛋糕卷[话题]#',
            'title': '香妃蛋糕也太香了吧🔥不需要卷❗️绝对的友好',
            'tags': ['今日快乐今日发', '吃货薯看这里', '香妃蛋糕', '小五卷蛋糕', '新手蛋糕卷'],
            'duration': 101.726,
            'thumbnail': r're:https?://sns-webpic-qc\.xhscdn\.com/\d+/[a-z0-9]+/[\w]+',
        }
    }]

    def _real_extract(self, url):
        display_id = self._match_id(url)
        webpage = self._download_webpage(url, display_id)
        initial_state = self._search_json(
            r'window\.__INITIAL_STATE__\s*=', webpage, 'initial state', display_id, transform_source=js_to_json)

        note_info = traverse_obj(initial_state, ('note', 'noteDetailMap', display_id, 'note'))
        video_info = traverse_obj(note_info, ('video', 'media', 'stream', ('h264', 'av1', 'h265'), ...))

        formats = []
        for info in video_info:
            format_info = traverse_obj(info, {
                'fps': ('fps', {int_or_none}),
                'width': ('width', {int_or_none}),
                'height': ('height', {int_or_none}),
                'vcodec': ('videoCodec', {str}),
                'acodec': ('audioCodec', {str}),
                'abr': ('audioBitrate', {int_or_none}),
                'vbr': ('videoBitrate', {int_or_none}),
                'audio_channels': ('audioChannels', {int_or_none}),
                'tbr': ('avgBitrate', {int_or_none}),
                'format': ('qualityType', {str}),
                'filesize': ('size', {int_or_none}),
                'duration': ('duration', {functools.partial(float_or_none, scale=1000)})
            })

            formats.extend(traverse_obj(info, (('mediaUrl', ('backupUrls', ...)), {
                lambda u: url_or_none(u) and {'url': u, **format_info}})))

        thumbnails = []