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,), allowable_methods=('GET', 'HEAD', 'POST'))
  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, metadata = None, 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             "html5": "1",
 222         }, cookies=cookies)
 223
 224         if r.status_code == 429:
 225             return None, None, None, 'banned', 'possible IP ban'
 226
 227         params = parse_qs(r.text)
 228         if 'errorcode' in params: # status=fail
 229             return None, None, None, 'malformed', params['reason'][0]
 230
 231         try:
 232             metadata = json.loads(params.get('player_response')[0])
 233         except:
 234             # XXX(HOTFIX): some requests are missing the player_response; don't
 235             # crash, but either try again or fail gracefully and the user shoud
 236             # retry.
 237             continue
 238         playabilityStatus = metadata['playabilityStatus']['status']
 239         if playabilityStatus != "OK":
 240             playabilityReason = metadata['playabilityStatus'].get('reason',
 241                     '//'.join(metadata['playabilityStatus'].get('messages',[])))
 242             player_error = f"{playabilityStatus}: {playabilityReason}"
 243             if playabilityStatus == "UNPLAYABLE":
 244                 continue  # try again with next el value (or fail as exhausted)
 245             # without videoDetails, there's only the error message
 246             maybe_metadata = metadata if 'videoDetails' in metadata else None
 247             return None, None, maybe_metadata, 'player', player_error
 248
 249         # livestreams have no adaptive/muxed formats:
 250         is_live = metadata['videoDetails'].get('isLive', False)
 251
 252         if not 'formats' in metadata['streamingData'] and not is_live:
 253             continue # no urls
 254
 255         formats = metadata['streamingData'].get('formats',[])
 256         for (i,v) in enumerate(formats):
 257             if not ('cipher' in v or 'signatureCipher' in v): continue
 258             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 259             formats[i]['url'] = unscramble(cipher, algo)
 260
 261         adaptive = metadata['streamingData'].get('adaptiveFormats',[])
 262         for (i,v) in enumerate(adaptive):
 263             if not ('cipher' in v or 'signatureCipher' in v): continue
 264             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 265             adaptive[i]['url'] = unscramble(cipher, algo)
 266
 267         stream_map = {
 268             'adaptive': adaptive, 'muxed': formats,
 269             'hlsManifestUrl': metadata['streamingData'].get('hlsManifestUrl'),
 270         }
 271
 272         url = sorted(formats, key=lambda k: k['height'], reverse=True)[0]['url'] \
 273             if not is_live else None
 274
 275         # ip-locked videos can be recovered if the proxy module is loaded:
 276         is_geolocked = 'gcr' in parse_qs(urlparse(url).query)
 277
 278         nonfatal = 'livestream' if is_live \
 279             else 'geolocked' if is_geolocked \
 280             else None
 281
 282         return url, stream_map, metadata, nonfatal, None
 283     else:
 284         return None, None, metadata, 'exhausted', player_error
 285
 286 def unscramble(cipher, algo):
 287     signature = list(cipher['s'][0])
 288     for c in algo.split():
 289         op, ix = re.match(r"([rsw])(\d+)?", c).groups()
 290         ix = int(ix) % len(signature) if ix else 0
 291         if op == 'r': signature = list(reversed(signature))
 292         if op == 's': signature = signature[ix:]
 293         if op == 'w': signature[0], signature[ix] = signature[ix], signature[0]
 294     sp = cipher.get('sp', ['signature'])[0]
 295     sig = cipher.get('sig', [''.join(signature)])[0]
 296     return f"{cipher['url'][0]}&{sp}={sig}"
 297
 298 def video_metadata(metadata):
 299     if not metadata:
 300         return {}
 301
 302     meta1 = metadata['videoDetails']
 303     meta2 = metadata['microformat']['playerMicroformatRenderer']
 304
 305     # sometimes, we receive the notification so early that the length is not
 306     # yet populated. Nothing we can do about it.
 307     length = int(meta2['lengthSeconds']) or int(meta1['lengthSeconds']) or None
 308
 309     published_at = meta2.get('liveBroadcastDetails',{}) \
 310         .get('startTimestamp', f"{meta2['publishDate']}T00:00:00Z")
 311
 312     # Note: 'premiere' videos have livestream=False and published= will be the
 313     # start of the premiere.
 314     return {
 315         'title': meta1['title'],
 316         'author': meta1['author'],
 317         'channel_id': meta1['channelId'],
 318         'published': published_at,
 319         'views': int(meta1['viewCount']),
 320         'length': length,
 321         'livestream': meta1['isLiveContent'],
 322     }
 323
 324 def store_video_metadata(video_id):
 325     # check if we know about it, and if not, fetch and store video metadata
 326     with sqlite3.connect(cf['global']['database']) as conn:
 327         c = conn.cursor()
 328         c.execute("SELECT 1 from videos where id = ?", (video_id,))
 329         new_video = len(c.fetchall()) < 1
 330         if new_video:
 331             _, _, meta, _, _ = get_video_info(video_id)
 332             if meta:
 333                 meta = video_metadata(meta)
 334                 c.execute("""
 335                     INSERT OR IGNORE INTO videos (id, channel_id, title, length, published, crawled)
 336                                    VALUES (?, ?, ?, ?, datetime(?), datetime(?))
 337                 """, (
 338                     video_id,
 339                     meta['channel_id'],
 340                     meta['title'],
 341                     meta['length'],
 342                     meta['published'],
 343                     meta['published'],
 344                 ))
 345                 c.execute("""
 346                     INSERT OR REPLACE INTO channels (id, name)
 347                                     VALUES (?, ?)
 348                 """, (meta['channel_id'], meta['author']))
 349
 350 def fetch_video_flags(token, video_ids):
 351     with sqlite3.connect(cf['global']['database']) as conn:
 352         c = conn.cursor()
 353         c.execute("""
 354             SELECT video_id,display
 355               FROM flags
 356              WHERE user = ?
 357                AND display IS NOT NULL
 358                AND video_id IN ({})
 359                -- AND display = 'pinned'
 360         """.format(",".join(["?"]*len(video_ids))), (token,*video_ids))
 361         flags = c.fetchall()
 362         pinned = [video for video,disp in flags if disp == 'pinned']
 363         hidden = [video for video,disp in flags if disp == 'hidden']
 364
 365         return pinned, hidden
 366
 367 from werkzeug.exceptions import NotFound
 368 class NoFallbackException(NotFound): pass
 369 def fallback_route(*args, **kwargs): # TODO: worthy as a flask-extension?
 370     """
 371     finds the next route that matches the current url rule, and executes it.
 372     args, kwargs: pass all arguments of the current route
 373     """
 374     from flask import current_app, request, g
 375
 376     # build a list of endpoints that match the current request's url rule:
 377     matching = [
 378         rule.endpoint
 379         for rule in current_app.url_map.iter_rules()
 380         if rule.rule == request.url_rule.rule
 381     ]
 382     current = matching.index(request.endpoint)
 383
 384     # since we can't change request.endpoint, we always get the original
 385     # endpoint back. so for repeated fall throughs, we use the g object to
 386     # increment how often we want to fall through.
 387     if not '_fallback_next' in g:
 388         g._fallback_next = 0
 389     g._fallback_next += 1
 390
 391     next_ep = current + g._fallback_next
 392
 393     if next_ep < len(matching):
 394         return current_app.view_functions[matching[next_ep]](*args, **kwargs)
 395     else:
 396         raise NoFallbackException
 397
 398 def websub_url_hmac(key, feed_id, timestamp, nonce):
 399     """ generate sha1 hmac, as required by websub/pubsubhubbub """
 400     sig_input = f"{feed_id}:{timestamp}:{nonce}".encode('ascii')
 401     return hmac.new(key.encode('ascii'), sig_input, hashlib.sha1).hexdigest()
 402
 403 def websub_body_hmac(key, body):
 404     return hmac.new(key.encode('ascii'), body, hashlib.sha1).hexdigest()
 405
 406 def flask_logger(msg, level="warning"):
 407     level = dict(
 408         CRITICAL=50,
 409         ERROR=40,
 410         WARNING=30,
 411         INFO=20,
 412         DEBUG=10,
 413         NOTSET=0,
 414     ).get(level.upper(), 0)
 415     try:
 416         from flask import current_app
 417         current_app.logger.log(level, msg)
 418     except:
 419         pass
 420
 421 def pp(*args):
 422     from pprint import pprint
 423     import sys, codecs
 424     pprint(args, stream=codecs.getwriter("utf-8")(sys.stderr.buffer))