[nebula] Add basic support for Nebula (refs ytdl-org#21258)

AUTHORS

@@ -246,3 +246,4 @@ Enes Solak
 Nathan Rossi
 Thomas van der Berg
 Luca Cherubin
+Henrik Heimbuerger

docs/supportedsites.md

@@ -548,6 +548,7 @@
  - **ndr:embed**
  - **ndr:embed:base**
  - **NDTV**
+ - **Nebula**
  - **NerdCubedFeed**
  - **netease:album**: 网易云音乐 - 专辑
  - **netease:djradio**: 网易云音乐 - 电台

youtube_dl/extractor/extractors.py

@@ -696,8 +696,9 @@
     NJoyEmbedIE,
 )
 from .ndtv import NDTVIE
-from .netzkino import NetzkinoIE
+from .nebula import NebulaIE
 from .nerdcubed import NerdCubedFeedIE
+from .netzkino import NetzkinoIE
 from .neteasemusic import (
     NetEaseMusicIE,
     NetEaseMusicAlbumIE,

youtube_dl/extractor/nebula.py

@@ -0,0 +1,132 @@
+# coding: utf-8
+from __future__ import unicode_literals
+
+import os
+
+from .common import InfoExtractor
+from ..utils import parse_iso8601
+
+COOKIE_NEBULA_AUTH = os.environ.get('COOKIE_NEBULA_AUTH')   # FIXME: a workaround for testing, because I couldn't figure out how to supply a cookiejar when running the unit tests
+
+
+class NebulaIE(InfoExtractor):
+    """
+    Nebula (https://watchnebula.com/) is a video platform created by the streamer community Standard. It hosts videos
+    off-YouTube from a small hand-picked group of creators.
+
+    All videos require a subscription to watch. There are no known freely available videos. So the test case is
+    disabled (but should pass when supplying a 'nebula-auth' cookie for an account with a valid subscription).
+
+    Nebula uses the Zype video infrastructure and this extractor is using the 'url_transparent' mode to hand off
+    video extraction to the Zype extractor.
+
+    This description has been last updated on 2020-04-07.
+    """
+
+    _VALID_URL = r'https?://(?:www\.)?watchnebula\.com/videos/(?P<id>[-\w]+)'   # the 'id' group is actually the slug, but we misname it 'id' to be able to use _match_id()
+    _TEST = {
+        'url': 'https://watchnebula.com/videos/that-time-disney-remade-beauty-and-the-beast',
+        'md5': 'fe79c4df8b3aa2fea98a93d027465c7e',
+        'info_dict': {
+            'id': '5c271b40b13fd613090034fd',
+            'ext': 'mp4',
+            'title': 'That Time Disney Remade Beauty and the Beast',
+            'description': 'Note: this video was originally posted on YouTube with the sponsor read included. We weren’t able to remove it without reducing video quality, so it’s presented here in its original context.',
+            'upload_date': '20180731',
+            'timestamp': 1533009600,
+            #'uploader': 'Lindsay Ellis',   # TODO: removed because unreliable/sometimes incorrect
+        }
+    }
+    _WORKING = False   # this is set to False because the test won't pass without an auth cookie for a (paid) subscription
+
+    def _extract_state_object(self, webpage, display_id):
+        """
+        As of 2020-04-07, every Nebula video page is a React base page, containing an initial state JSON in a script
+        tag. This function is extracting this script tag, parsing it as JSON.
+        """
+        initial_state_object = self._search_regex(r'<script id="initial-app-state" type="application/json">(.+?)</script>', webpage, 'initial_state')
+        metadata = self._parse_json(initial_state_object, video_id=display_id)   # TODO: we don't have the real video ID yet, is it okay to pass the display_id instead?
+
+        return metadata
+
+    def _extract_video_metadata(self, state_object, display_id):
+        """
+        The state object contains a videos.byURL dictionary, which maps URL display IDs to video IDs. Using the
+        video ID, we can then extract a dictionary with various meta data about the video itself.
+        """
+        video_id = state_object['videos']['byURL'][display_id]
+        video_meta = state_object['videos']['byID'][video_id]
+
+        return video_id, video_meta
+
+    def _extract_video_url(self, webpage, state_object, video_id):
+        """
+        To get the embed URL of the actual video stream, we could reconstruct it from the video ID, but it seems a
+        bit more stable to extract the iframe source that links to the video.
+        """
+        iframe = self._search_regex(r'<iframe(.+?)</iframe>', webpage, 'iframe', fatal=False)
+        video_url = self._search_regex(r'src="(.+?)"', iframe, 'iframe-src', fatal=False) if iframe else None
+
+        # fallback: reconstruct using video ID and access token from state object
+        if not video_url:
+            access_token = state_object['account']['userInfo']['zypeAuthInfo']['accessToken']
+            video_url = 'https://player.zype.com/embed/{video_id}.html?access_token={access_token}'.format(video_id=video_id, access_token=access_token)
+
+        return video_url
+
+    def _extract_uploader(self, video_meta):
+        """
+        Nebula doesn't really seem to have the concept of an uploader internally, videos are often organized
+        more like a (TV) series than by uploader. But in the example case, Lindsay Ellis is the creator, so
+        I'll go with this for now.
+        """
+        return video_meta['categories'][0]['value'][0]
+
+    def _real_extract(self, url):
+        # FIXME: a workaround for testing, because I couldn't figure out how to supply a cookiejar when running the unit tests
+        if COOKIE_NEBULA_AUTH:
+            self._set_cookie('watchnebula.com', 'nebula-auth', COOKIE_NEBULA_AUTH)
+
+        # extract the video's display ID from the URL (we'll retrieve the video ID later)
+        display_id = self._match_id(url)
+
+        # download the page
+        webpage = self._download_webpage(url, video_id=display_id)    # TODO: what video ID do I supply, as I don't know it yet? _download_webpage doesn't accept a display_id instead...
+
+        # extract the state object from the webpage, and then retrieve video meta data from it
+        state_object = self._extract_state_object(webpage, display_id)
+        video_id, video_meta = self._extract_video_metadata(state_object, display_id)
+
+        # extract the video URL from the webpage
+        video_url = self._extract_video_url(webpage, state_object, video_id)
+
+        return {
+            'id': video_id,
+            'display_id': display_id,
+
+            # we're passing this video URL on to the 'Zype' extractor (that's the video infrastructure that Nebula is
+            # built on top of) and use the 'url_transparent' type to indicate that our meta data should be better than
+            # whatever the Zype extractor is able to identify
+            '_type': 'url_transparent',
+            'ie_key': 'Zype',
+            'url': video_url,
+
+            # the meta data we were able to extract from Nebula
+            'title': video_meta['title'],
+            'description': video_meta['description'],
+            'timestamp': parse_iso8601(video_meta['published_at']),
+            #'uploader': self._extract_uploader(video_meta),   # TODO: removed because unreliable/sometimes incorrect
+            'thumbnails': [
+                {
+                    'id': tn['name'],   # this appears to be null in all cases I've seen
+                    'url': tn['url'],
+                    'width': tn['width'],
+                    'height': tn['height'],
+                } for tn in video_meta['thumbnails']
+            ],
+            'duration': video_meta['duration'],
+            # TODO: uploader_url: the video page clearly links to this (in the example case: /lindsayellis), but I cannot figure out where it gets it from!
+            # TODO: channel
+            # TODO: channel_id
+            # TODO: channel_url
+        }