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     for el in ['embedded', 'detailpage']:#sometimes, only one or the other works
 211         r = requests.get("https://www.youtube.com/get_video_info", {
 212             "video_id": video_id,
 213             "eurl": f"https://youtube.googleapis.com/v/{video_id}",
 214             "el": el,
 215             "sts": sts,
 216             "hl": "en_US",
 217         })
 218
 219         if r.status_code == 429:
 220             return None, None, None, 'banned', 'possible IP ban'
 221
 222         params = parse_qs(r.text)
 223         if 'errorcode' in params: # status=fail
 224             return None, None, None, 'malformed', params['reason'][0]
 225
 226         metadata = json.loads(params.get('player_response')[0])
 227         playabilityStatus = metadata['playabilityStatus']['status']
 228         if playabilityStatus != "OK":
 229             playabilityReason = metadata['playabilityStatus'].get('reason',
 230                     '//'.join(metadata['playabilityStatus'].get('messages',[])))
 231             player_error = f"{playabilityStatus}: {playabilityReason}"
 232             if playabilityStatus == "UNPLAYABLE":
 233                 continue  # try again with next el value (or fail as exhausted)
 234             # without videoDetails, there's only the error message
 235             maybe_metadata = metadata if 'videoDetails' in metadata else None
 236             return None, None, maybe_metadata, 'player', player_error
 237         if metadata['videoDetails'].get('isLive', False):
 238             return None, None, metadata, 'livestream', None
 239
 240         if not 'formats' in metadata['streamingData']:
 241             continue # no urls
 242
 243         formats = metadata['streamingData'].get('formats',[])
 244         for (i,v) in enumerate(formats):
 245             if not ('cipher' in v or 'signatureCipher' in v): continue
 246             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 247             formats[i]['url'] = unscramble(cipher, algo)
 248
 249         adaptive = metadata['streamingData'].get('adaptiveFormats',[])
 250         for (i,v) in enumerate(adaptive):
 251             if not ('cipher' in v or 'signatureCipher' in v): continue
 252             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 253             adaptive[i]['url'] = unscramble(cipher, algo)
 254
 255         stream_map = {'adaptive': adaptive, 'muxed': formats}
 256         stream_map.update({'hlsManifestUrl': metadata['streamingData'].get('hlsManifestUrl')})
 257         stream_map.update({'dashManifestUrl': metadata['streamingData'].get('dashManifestUrl')})
 258
 259         # todo: check if we have urls or try again
 260         url = sorted(formats, key=lambda k: k['height'], reverse=True)[0]['url']
 261
 262         # ip-locked videos can be recovered if the proxy module is loaded:
 263         is_geolocked = 'geolocked' if 'gcr' in parse_qs(urlparse(url).query) else None
 264
 265         return url, stream_map, metadata, is_geolocked, None
 266     else:
 267         return None, None, metadata, 'exhausted', player_error
 268
 269 def unscramble(cipher, algo):
 270     signature = list(cipher['s'][0])
 271     for c in algo.split():
 272         op, ix = re.match(r"([rsw])(\d+)?", c).groups()
 273         ix = int(ix) % len(signature) if ix else 0
 274         if op == 'r': signature = list(reversed(signature))
 275         if op == 's': signature = signature[ix:]
 276         if op == 'w': signature[0], signature[ix] = signature[ix], signature[0]
 277     sp = cipher.get('sp', ['signature'])[0]
 278     sig = cipher.get('sig', [''.join(signature)])[0]
 279     return f"{cipher['url'][0]}&{sp}={sig}"
 280
 281 def video_metadata(metadata):
 282     if not metadata:
 283         return {}
 284
 285     meta1 = metadata['videoDetails']
 286     meta2 = metadata['microformat']['playerMicroformatRenderer']
 287
 288     # sometimes, we receive the notification so early that the length is not
 289     # yet populated. Nothing we can do about it.
 290     length = int(meta2['lengthSeconds']) or int(meta1['lengthSeconds']) or None
 291
 292     published_at = meta2.get('liveBroadcastDetails',{}) \
 293         .get('startTimestamp', f"{meta2['publishDate']}T00:00:00Z")
 294
 295     # Note: 'premiere' videos have livestream=False and published= will be the
 296     # start of the premiere.
 297     return {
 298         'title': meta1['title'],
 299         'author': meta1['author'],
 300         'channel_id': meta1['channelId'],
 301         'published': published_at,
 302         'views': int(meta1['viewCount']),
 303         'length': length,
 304         'livestream': meta1['isLiveContent'],
 305     }
 306
 307 def store_video_metadata(video_id):
 308     # check if we know about it, and if not, fetch and store video metadata
 309     with sqlite3.connect(cf['global']['database']) as conn:
 310         c = conn.cursor()
 311         c.execute("SELECT 1 from videos where id = ?", (video_id,))
 312         new_video = len(c.fetchall()) < 1
 313         if new_video:
 314             _, _, meta, _, _ = get_video_info(video_id)
 315             if meta:
 316                 meta = video_metadata(meta)
 317                 c.execute("""
 318                     INSERT OR IGNORE INTO videos (id, channel_id, title, length, published, crawled)
 319                                    VALUES (?, ?, ?, ?, datetime(?), datetime(?))
 320                 """, (
 321                     video_id,
 322                     meta['channel_id'],
 323                     meta['title'],
 324                     meta['length'],
 325                     meta['published'],
 326                     meta['published'],
 327                 ))
 328                 c.execute("""
 329                     INSERT OR REPLACE INTO channels (id, name)
 330                                     VALUES (?, ?)
 331                 """, (meta['channel_id'], meta['author']))
 332
 333 def fetch_video_flags(token, video_ids):
 334     with sqlite3.connect(cf['global']['database']) as conn:
 335         c = conn.cursor()
 336         c.execute("""
 337             SELECT video_id,display
 338               FROM flags
 339              WHERE user = ?
 340                AND display IS NOT NULL
 341                AND video_id IN ({})
 342                -- AND display = 'pinned'
 343         """.format(",".join(["?"]*len(video_ids))), (token,*video_ids))
 344         flags = c.fetchall()
 345         pinned = [video for video,disp in flags if disp == 'pinned']
 346         hidden = [video for video,disp in flags if disp == 'hidden']
 347
 348         return pinned, hidden
 349
 350 from werkzeug.exceptions import NotFound
 351 class NoFallbackException(NotFound): pass
 352 def fallback_route(*args, **kwargs): # TODO: worthy as a flask-extension?
 353     """
 354     finds the next route that matches the current url rule, and executes it.
 355     args, kwargs: pass all arguments of the current route
 356     """
 357     from flask import current_app, request, g
 358
 359     # build a list of endpoints that match the current request's url rule:
 360     matching = [
 361         rule.endpoint
 362         for rule in current_app.url_map.iter_rules()
 363         if rule.rule == request.url_rule.rule
 364     ]
 365     current = matching.index(request.endpoint)
 366
 367     # since we can't change request.endpoint, we always get the original
 368     # endpoint back. so for repeated fall throughs, we use the g object to
 369     # increment how often we want to fall through.
 370     if not '_fallback_next' in g:
 371         g._fallback_next = 0
 372     g._fallback_next += 1
 373
 374     next_ep = current + g._fallback_next
 375
 376     if next_ep < len(matching):
 377         return current_app.view_functions[matching[next_ep]](*args, **kwargs)
 378     else:
 379         raise NoFallbackException
 380
 381 def websub_url_hmac(key, feed_id, timestamp, nonce):
 382     """ generate sha1 hmac, as required by websub/pubsubhubbub """
 383     sig_input = f"{feed_id}:{timestamp}:{nonce}".encode('ascii')
 384     return hmac.new(key.encode('ascii'), sig_input, hashlib.sha1).hexdigest()
 385
 386 def websub_body_hmac(key, body):
 387     return hmac.new(key.encode('ascii'), body, hashlib.sha1).hexdigest()
 388
 389 def flask_logger(msg, level="warning"):
 390     try:
 391         from flask import current_app
 392         current_app.logger.log(level, msg)
 393     except:
 394         pass
 395
 396 def pp(*args):
 397     from pprint import pprint
 398     import sys, codecs
 399     pprint(args, stream=codecs.getwriter("utf-8")(sys.stderr.buffer))