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