app/common/common.py

   1 import os
   2 import re
   3 import json
   4 import base64
   5 import sqlite3
   6 import requests
   7 import hmac, hashlib
   8 import requests_cache
   9 import dateutil.parser
  10 from xml.etree import ElementTree
  11 from configparser import ConfigParser
  12 from datetime import datetime, timezone
  13 from urllib.parse import parse_qs, urlparse
  14
  15 cf = ConfigParser()
  16 config_filename = os.environ.get('YT_CONFIG', '/etc/yt/config.ini')
  17 cf.read(config_filename)
  18 if not 'global' in cf: # todo: full config check
  19     raise Exception("Configuration file not found or empty")
  20
  21 # Note: currently expiring after 10 minutes. googlevideo-urls are valid for 5h59m, but this makes reddit very stale and premiere videos won't start.  TODO: exipre when video is livestream/premiere/etc
  22 requests_cache.install_cache(backend='memory', expire_after=10*60, allowable_codes=(200,))
  23
  24 # Note: requests-cache doesn't use redis expiry, so we need this in all backends:
  25 # https://github.com/reclosedev/requests-cache/issues/58#issuecomment-164537971
  26 # TODO: only run for long-running processes, i.e. the frontend
  27 from threading import Timer
  28 def purge_cache(sec):
  29     requests_cache.remove_expired_responses()
  30     t = Timer(sec, purge_cache, args=(sec,))
  31     t.setDaemon(True)
  32     t.start()
  33 purge_cache(10*60)
  34
  35 # for debugging purposes, monkey patch requests session to store each requests-request in a flask-request's g object (url and response). we can then use a flask error_handler to include the request data in the error log.
  36 # since we also call config from outside the flask appcontext, it is wrapped in a try-catch block.
  37 from flask import g
  38 import requests
  39 from requests import Session as OriginalSession
  40 class _NSASession(OriginalSession):
  41     def request(self, method, url, params=None, data=None, **kwargs):
  42         response = super(_NSASession, self).request(
  43             method, url, params, data, **kwargs
  44             )
  45         try:
  46             if 'api_requests' not in g:
  47                 g.api_requests = []
  48             g.api_requests.append((url, params, response.text))
  49         except RuntimeError: pass # not within flask (e.g. utils.py)
  50         return response
  51 requests.Session = requests.sessions.Session = _NSASession
  52
  53 def fetch_xml(feed_type, feed_id):
  54     # TODO: handle requests.exceptions.ConnectionError
  55     r = requests.get("https://www.youtube.com/feeds/videos.xml", {
  56         feed_type: feed_id,
  57     })
  58     if not r.ok:
  59         return None
  60
  61     return r.content
  62
  63 def parse_xml(xmldata):
  64     ns = {
  65         'atom':"http://www.w3.org/2005/Atom",
  66         'yt': "http://www.youtube.com/xml/schemas/2015",
  67         'media':"http://search.yahoo.com/mrss/",
  68         'at': "http://purl.org/atompub/tombstones/1.0",
  69     }
  70
  71     feed = ElementTree.fromstring(xmldata)
  72
  73     if feed.find('at:deleted-entry',ns):
  74         (_,_,vid) = feed.find('at:deleted-entry',ns).get('ref').rpartition(':')
  75         return None, None, [{'deleted': True, 'video_id': vid}], None, None
  76
  77     title = feed.find('atom:title',ns).text
  78     author = feed.find('atom:author/atom:name',ns).text \
  79         if feed.find('atom:author',ns) else None
  80     # for /user/<> endpoint: find out UC-id:
  81     # for playlists: this is who created the playlist:
  82     try:   channel_id = feed.find('yt:channelId',ns).text
  83     except:channel_id=None # XXX: why does ternary not work!?
  84     # for pullsub: if this exists, we're looking at a playlist:
  85     try:   playlist_id = feed.find('yt:playlistId',ns).text
  86     except:playlist_id=None # XXX: why does ternary not work!?
  87     videos = []
  88     for entry in feed.findall('atom:entry',ns):
  89         videos.append({
  90             'video_id': entry.find('yt:videoId',ns).text,
  91             'title': entry.find('atom:title',ns).text,
  92             'published': entry.find('atom:published',ns).text,
  93             'channel_id': entry.find('yt:channelId',ns).text,
  94             'author': entry.find('atom:author',ns).find('atom:name',ns).text,
  95             # extra fields for pull_subs/webhook:
  96             'updated': entry.find('atom:updated',ns).text,
  97         })
  98
  99     return title, author, videos, channel_id, playlist_id
 100
 101 def update_channel(db, xmldata, from_webhook=False):
 102     if not xmldata: return False
 103
 104     # Note: websub does not return global author, hence taking from first video
 105     title, author, videos, channel, playlist = parse_xml(xmldata)
 106
 107     c = db.cursor()
 108     for i, video in enumerate(videos):
 109         if video.get('deleted'):
 110             # Note: Deletion events are not just fired for actual deletions,
 111             # but also for unlisting videos and livestreams that just ended
 112             # (even postLiveDVR ones). Hence, we don't follow it.
 113             flask_logger(f"ignoring deleted/unlisted/ended video/stream {video['video_id']}")
 114             break
 115
 116         c.execute("SELECT 1 FROM videos WHERE id=?",(video['video_id'],))
 117         new_video = len(c.fetchall()) < 1
 118         if new_video:
 119             flask_logger(f"new video {video['video_id']}")
 120             _, _, meta, _, _ = get_video_info(video['video_id'])
 121             # The 'published' timestamp sent in websub POSTs are often wrong (e.g.:
 122             # video gets uploaded as unlisted on day A and set to public on day B;
 123             # the webhook is sent on day B, but 'published' says A. The video
 124             # therefore looks like it's just an update to an older video).
 125             # g_v_i gives is the date the video was published to viewers, so we
 126             # prefer that. But since g_v_i only returns the date without time,
 127             # we still use xmlfeed's date if it's the same date.
 128             published = dateutil.parser.parse(video['published'])
 129             length = None
 130             livestream = None
 131             if meta:
 132                 meta = video_metadata(meta)
 133                 published2 = dateutil.parser.parse(meta['published'])
 134                 flask_logger(f"published {published} / {published2}")
 135                 if published < published2: # g_v_i date is more accurate:
 136                     published = published2
 137                 length = meta['length']
 138                 livestream = meta['livestream']
 139
 140             now = datetime.now(timezone.utc)
 141
 142             # we pretend that all videos uploaded this week were uploaded just
 143             # now, so the user sees it at the top of the feed, and it doesn't
 144             # get inserted somewhere further down.
 145             if (now - published).days < 7:
 146                 timestamp = now
 147             else:#, it's just an update to an older video.
 148                 timestamp = published
 149
 150             c.execute("""
 151                 INSERT OR IGNORE INTO videos
 152                     (id, channel_id, title, length, livestream, published, crawled)
 153                 VALUES (?, ?, ?, ?, ?, datetime(?), datetime(?))
 154             """, (
 155                 video['video_id'],
 156                 video['channel_id'],
 157                 video['title'],
 158                 length,
 159                 livestream,
 160                 video['published'],
 161                 timestamp
 162             ))
 163         else:
 164             # update video title (everything else can't change)
 165             c.execute("""
 166                 UPDATE OR IGNORE videos
 167                     SET title = ?
 168                     WHERE id = ?
 169             """, (
 170                 video['title'],
 171                 video['video_id'],
 172             ))
 173
 174         # for channels, this is obviously always the same, but playlists can
 175         # consist of videos from different channels:
 176         if i == 0 or playlist:
 177             c.execute("""
 178                 INSERT OR REPLACE INTO channels (id, name)
 179                                 VALUES (?, ?)
 180             """, (video['channel_id'], video['author']))
 181
 182         # keep track of which videos are in a playlist, so we can show the user
 183         # why a video is in their feed:
 184         if playlist:
 185             c.execute("""
 186                 INSERT OR IGNORE INTO playlist_videos (video_id, playlist_id)
 187                                VALUES (?, ?)
 188             """, (video['video_id'], playlist))
 189
 190     if playlist and not from_webhook: # Note: playlists can't get updated via websub
 191         c.execute("""
 192             INSERT OR REPLACE INTO playlists (id, name, author)
 193                             VALUES (?, ?, ?)
 194             """, (playlist, title, channel))
 195         c.execute("""
 196             INSERT OR REPLACE INTO channels (id, name)
 197                             VALUES (?, ?)
 198         """, (channel, author))
 199
 200     db.commit()
 201
 202     return True
 203
 204 def get_video_info(video_id, sts=0, algo=""):
 205     """
 206     returns: best-quality muxed video stream, stream map, player_response, error-type/mesage
 207     error types: player, malformed, livestream, geolocked, exhausted
 208     """
 209     player_error = None # for 'exhausted'
 210     with sqlite3.connect(cf['global']['database']) as conn:
 211         c = conn.cursor()
 212         c.execute("SELECT * FROM captcha_cookies")
 213         cookies = dict(c.fetchall())
 214     for el in ['embedded', 'detailpage']:#sometimes, only one or the other works
 215         r = requests.get("https://www.youtube.com/get_video_info", {
 216             "video_id": video_id,
 217             "eurl": f"https://youtube.googleapis.com/v/{video_id}",
 218             "el": el,
 219             "sts": sts,
 220             "hl": "en_US",
 221         }, cookies=cookies)
 222
 223         if r.status_code == 429:
 224             return None, None, None, 'banned', 'possible IP ban'
 225
 226         params = parse_qs(r.text)
 227         if 'errorcode' in params: # status=fail
 228             return None, None, None, 'malformed', params['reason'][0]
 229
 230         metadata = json.loads(params.get('player_response')[0])
 231         playabilityStatus = metadata['playabilityStatus']['status']
 232         if playabilityStatus != "OK":
 233             playabilityReason = metadata['playabilityStatus'].get('reason',
 234                     '//'.join(metadata['playabilityStatus'].get('messages',[])))
 235             player_error = f"{playabilityStatus}: {playabilityReason}"
 236             if playabilityStatus == "UNPLAYABLE":
 237                 continue  # try again with next el value (or fail as exhausted)
 238             # without videoDetails, there's only the error message
 239             maybe_metadata = metadata if 'videoDetails' in metadata else None
 240             return None, None, maybe_metadata, 'player', player_error
 241         if metadata['videoDetails'].get('isLive', False):
 242             return None, None, metadata, 'livestream', None
 243
 244         if not 'formats' in metadata['streamingData']:
 245             continue # no urls
 246
 247         formats = metadata['streamingData'].get('formats',[])
 248         for (i,v) in enumerate(formats):
 249             if not ('cipher' in v or 'signatureCipher' in v): continue
 250             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 251             formats[i]['url'] = unscramble(cipher, algo)
 252
 253         adaptive = metadata['streamingData'].get('adaptiveFormats',[])
 254         for (i,v) in enumerate(adaptive):
 255             if not ('cipher' in v or 'signatureCipher' in v): continue
 256             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 257             adaptive[i]['url'] = unscramble(cipher, algo)
 258
 259         stream_map = {'adaptive': adaptive, 'muxed': formats}
 260         stream_map.update({'hlsManifestUrl': metadata['streamingData'].get('hlsManifestUrl')})
 261         stream_map.update({'dashManifestUrl': metadata['streamingData'].get('dashManifestUrl')})
 262
 263         # todo: check if we have urls or try again
 264         url = sorted(formats, key=lambda k: k['height'], reverse=True)[0]['url']
 265
 266         # ip-locked videos can be recovered if the proxy module is loaded:
 267         is_geolocked = 'geolocked' if 'gcr' in parse_qs(urlparse(url).query) else None
 268
 269         return url, stream_map, metadata, is_geolocked, None
 270     else:
 271         return None, None, metadata, 'exhausted', player_error
 272
 273 def unscramble(cipher, algo):
 274     signature = list(cipher['s'][0])
 275     for c in algo.split():
 276         op, ix = re.match(r"([rsw])(\d+)?", c).groups()
 277         ix = int(ix) % len(signature) if ix else 0
 278         if op == 'r': signature = list(reversed(signature))
 279         if op == 's': signature = signature[ix:]
 280         if op == 'w': signature[0], signature[ix] = signature[ix], signature[0]
 281     sp = cipher.get('sp', ['signature'])[0]
 282     sig = cipher.get('sig', [''.join(signature)])[0]
 283     return f"{cipher['url'][0]}&{sp}={sig}"
 284
 285 def video_metadata(metadata):
 286     if not metadata:
 287         return {}
 288
 289     meta1 = metadata['videoDetails']
 290     meta2 = metadata['microformat']['playerMicroformatRenderer']
 291
 292     # sometimes, we receive the notification so early that the length is not
 293     # yet populated. Nothing we can do about it.
 294     length = int(meta2['lengthSeconds']) or int(meta1['lengthSeconds']) or None
 295
 296     published_at = meta2.get('liveBroadcastDetails',{}) \
 297         .get('startTimestamp', f"{meta2['publishDate']}T00:00:00Z")
 298
 299     # Note: 'premiere' videos have livestream=False and published= will be the
 300     # start of the premiere.
 301     return {
 302         'title': meta1['title'],
 303         'author': meta1['author'],
 304         'channel_id': meta1['channelId'],
 305         'published': published_at,
 306         'views': int(meta1['viewCount']),
 307         'length': length,
 308         'livestream': meta1['isLiveContent'],
 309     }
 310
 311 def store_video_metadata(video_id):
 312     # check if we know about it, and if not, fetch and store video metadata
 313     with sqlite3.connect(cf['global']['database']) as conn:
 314         c = conn.cursor()
 315         c.execute("SELECT 1 from videos where id = ?", (video_id,))
 316         new_video = len(c.fetchall()) < 1
 317         if new_video:
 318             _, _, meta, _, _ = get_video_info(video_id)
 319             if meta:
 320                 meta = video_metadata(meta)
 321                 c.execute("""
 322                     INSERT OR IGNORE INTO videos (id, channel_id, title, length, published, crawled)
 323                                    VALUES (?, ?, ?, ?, datetime(?), datetime(?))
 324                 """, (
 325                     video_id,
 326                     meta['channel_id'],
 327                     meta['title'],
 328                     meta['length'],
 329                     meta['published'],
 330                     meta['published'],
 331                 ))
 332                 c.execute("""
 333                     INSERT OR REPLACE INTO channels (id, name)
 334                                     VALUES (?, ?)
 335                 """, (meta['channel_id'], meta['author']))
 336
 337 def fetch_video_flags(token, video_ids):
 338     with sqlite3.connect(cf['global']['database']) as conn:
 339         c = conn.cursor()
 340         c.execute("""
 341             SELECT video_id,display
 342               FROM flags
 343              WHERE user = ?
 344                AND display IS NOT NULL
 345                AND video_id IN ({})
 346                -- AND display = 'pinned'
 347         """.format(",".join(["?"]*len(video_ids))), (token,*video_ids))
 348         flags = c.fetchall()
 349         pinned = [video for video,disp in flags if disp == 'pinned']
 350         hidden = [video for video,disp in flags if disp == 'hidden']
 351
 352         return pinned, hidden
 353
 354 from werkzeug.exceptions import NotFound
 355 class NoFallbackException(NotFound): pass
 356 def fallback_route(*args, **kwargs): # TODO: worthy as a flask-extension?
 357     """
 358     finds the next route that matches the current url rule, and executes it.
 359     args, kwargs: pass all arguments of the current route
 360     """
 361     from flask import current_app, request, g
 362
 363     # build a list of endpoints that match the current request's url rule:
 364     matching = [
 365         rule.endpoint
 366         for rule in current_app.url_map.iter_rules()
 367         if rule.rule == request.url_rule.rule
 368     ]
 369     current = matching.index(request.endpoint)
 370
 371     # since we can't change request.endpoint, we always get the original
 372     # endpoint back. so for repeated fall throughs, we use the g object to
 373     # increment how often we want to fall through.
 374     if not '_fallback_next' in g:
 375         g._fallback_next = 0
 376     g._fallback_next += 1
 377
 378     next_ep = current + g._fallback_next
 379
 380     if next_ep < len(matching):
 381         return current_app.view_functions[matching[next_ep]](*args, **kwargs)
 382     else:
 383         raise NoFallbackException
 384
 385 def websub_url_hmac(key, feed_id, timestamp, nonce):
 386     """ generate sha1 hmac, as required by websub/pubsubhubbub """
 387     sig_input = f"{feed_id}:{timestamp}:{nonce}".encode('ascii')
 388     return hmac.new(key.encode('ascii'), sig_input, hashlib.sha1).hexdigest()
 389
 390 def websub_body_hmac(key, body):
 391     return hmac.new(key.encode('ascii'), body, hashlib.sha1).hexdigest()
 392
 393 def flask_logger(msg, level="warning"):
 394     level = dict(
 395         CRITICAL=50,
 396         ERROR=40,
 397         WARNING=30,
 398         INFO=20,
 399         DEBUG=10,
 400         NOTSET=0,
 401     ).get(level.upper(), 0)
 402     try:
 403         from flask import current_app
 404         current_app.logger.log(level, msg)
 405     except:
 406         pass
 407
 408 def pp(*args):
 409     from pprint import pprint
 410     import sys, codecs
 411     pprint(args, stream=codecs.getwriter("utf-8")(sys.stderr.buffer))