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