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
 242         # livestreams have no adaptive/muxed formats:
 243         is_live = metadata['videoDetails'].get('isLive', False)
 244
 245         if not 'formats' in metadata['streamingData'] and not is_live:
 246             continue # no urls
 247
 248         formats = metadata['streamingData'].get('formats',[])
 249         for (i,v) in enumerate(formats):
 250             if not ('cipher' in v or 'signatureCipher' in v): continue
 251             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 252             formats[i]['url'] = unscramble(cipher, algo)
 253
 254         adaptive = metadata['streamingData'].get('adaptiveFormats',[])
 255         for (i,v) in enumerate(adaptive):
 256             if not ('cipher' in v or 'signatureCipher' in v): continue
 257             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 258             adaptive[i]['url'] = unscramble(cipher, algo)
 259
 260         stream_map = {
 261             'adaptive': adaptive, 'muxed': formats,
 262             'hlsManifestUrl': metadata['streamingData'].get('hlsManifestUrl'),
 263         }
 264
 265         url = sorted(formats, key=lambda k: k['height'], reverse=True)[0]['url'] \
 266             if not is_live else None
 267
 268         # ip-locked videos can be recovered if the proxy module is loaded:
 269         is_geolocked = 'gcr' in parse_qs(urlparse(url).query)
 270
 271         nonfatal = 'livestream' if is_live \
 272             else 'geolocked' if is_geolocked \
 273             else None
 274
 275         return url, stream_map, metadata, nonfatal, None
 276     else:
 277         return None, None, metadata, 'exhausted', player_error
 278
 279 def unscramble(cipher, algo):
 280     signature = list(cipher['s'][0])
 281     for c in algo.split():
 282         op, ix = re.match(r"([rsw])(\d+)?", c).groups()
 283         ix = int(ix) % len(signature) if ix else 0
 284         if op == 'r': signature = list(reversed(signature))
 285         if op == 's': signature = signature[ix:]
 286         if op == 'w': signature[0], signature[ix] = signature[ix], signature[0]
 287     sp = cipher.get('sp', ['signature'])[0]
 288     sig = cipher.get('sig', [''.join(signature)])[0]
 289     return f"{cipher['url'][0]}&{sp}={sig}"
 290
 291 def video_metadata(metadata):
 292     if not metadata:
 293         return {}
 294
 295     meta1 = metadata['videoDetails']
 296     meta2 = metadata['microformat']['playerMicroformatRenderer']
 297
 298     # sometimes, we receive the notification so early that the length is not
 299     # yet populated. Nothing we can do about it.
 300     length = int(meta2['lengthSeconds']) or int(meta1['lengthSeconds']) or None
 301
 302     published_at = meta2.get('liveBroadcastDetails',{}) \
 303         .get('startTimestamp', f"{meta2['publishDate']}T00:00:00Z")
 304
 305     # Note: 'premiere' videos have livestream=False and published= will be the
 306     # start of the premiere.
 307     return {
 308         'title': meta1['title'],
 309         'author': meta1['author'],
 310         'channel_id': meta1['channelId'],
 311         'published': published_at,
 312         'views': int(meta1['viewCount']),
 313         'length': length,
 314         'livestream': meta1['isLiveContent'],
 315     }
 316
 317 def store_video_metadata(video_id):
 318     # check if we know about it, and if not, fetch and store video metadata
 319     with sqlite3.connect(cf['global']['database']) as conn:
 320         c = conn.cursor()
 321         c.execute("SELECT 1 from videos where id = ?", (video_id,))
 322         new_video = len(c.fetchall()) < 1
 323         if new_video:
 324             _, _, meta, _, _ = get_video_info(video_id)
 325             if meta:
 326                 meta = video_metadata(meta)
 327                 c.execute("""
 328                     INSERT OR IGNORE INTO videos (id, channel_id, title, length, published, crawled)
 329                                    VALUES (?, ?, ?, ?, datetime(?), datetime(?))
 330                 """, (
 331                     video_id,
 332                     meta['channel_id'],
 333                     meta['title'],
 334                     meta['length'],
 335                     meta['published'],
 336                     meta['published'],
 337                 ))
 338                 c.execute("""
 339                     INSERT OR REPLACE INTO channels (id, name)
 340                                     VALUES (?, ?)
 341                 """, (meta['channel_id'], meta['author']))
 342
 343 def fetch_video_flags(token, video_ids):
 344     with sqlite3.connect(cf['global']['database']) as conn:
 345         c = conn.cursor()
 346         c.execute("""
 347             SELECT video_id,display
 348               FROM flags
 349              WHERE user = ?
 350                AND display IS NOT NULL
 351                AND video_id IN ({})
 352                -- AND display = 'pinned'
 353         """.format(",".join(["?"]*len(video_ids))), (token,*video_ids))
 354         flags = c.fetchall()
 355         pinned = [video for video,disp in flags if disp == 'pinned']
 356         hidden = [video for video,disp in flags if disp == 'hidden']
 357
 358         return pinned, hidden
 359
 360 from werkzeug.exceptions import NotFound
 361 class NoFallbackException(NotFound): pass
 362 def fallback_route(*args, **kwargs): # TODO: worthy as a flask-extension?
 363     """
 364     finds the next route that matches the current url rule, and executes it.
 365     args, kwargs: pass all arguments of the current route
 366     """
 367     from flask import current_app, request, g
 368
 369     # build a list of endpoints that match the current request's url rule:
 370     matching = [
 371         rule.endpoint
 372         for rule in current_app.url_map.iter_rules()
 373         if rule.rule == request.url_rule.rule
 374     ]
 375     current = matching.index(request.endpoint)
 376
 377     # since we can't change request.endpoint, we always get the original
 378     # endpoint back. so for repeated fall throughs, we use the g object to
 379     # increment how often we want to fall through.
 380     if not '_fallback_next' in g:
 381         g._fallback_next = 0
 382     g._fallback_next += 1
 383
 384     next_ep = current + g._fallback_next
 385
 386     if next_ep < len(matching):
 387         return current_app.view_functions[matching[next_ep]](*args, **kwargs)
 388     else:
 389         raise NoFallbackException
 390
 391 def websub_url_hmac(key, feed_id, timestamp, nonce):
 392     """ generate sha1 hmac, as required by websub/pubsubhubbub """
 393     sig_input = f"{feed_id}:{timestamp}:{nonce}".encode('ascii')
 394     return hmac.new(key.encode('ascii'), sig_input, hashlib.sha1).hexdigest()
 395
 396 def websub_body_hmac(key, body):
 397     return hmac.new(key.encode('ascii'), body, hashlib.sha1).hexdigest()
 398
 399 def flask_logger(msg, level="warning"):
 400     level = dict(
 401         CRITICAL=50,
 402         ERROR=40,
 403         WARNING=30,
 404         INFO=20,
 405         DEBUG=10,
 406         NOTSET=0,
 407     ).get(level.upper(), 0)
 408     try:
 409         from flask import current_app
 410         current_app.logger.log(level, msg)
 411     except:
 412         pass
 413
 414 def pp(*args):
 415     from pprint import pprint
 416     import sys, codecs
 417     pprint(args, stream=codecs.getwriter("utf-8")(sys.stderr.buffer))