app/frontend.py

   1 import re
   2 import time
   3 import hmac
   4 import hashlib
   5 import sqlite3
   6 import secrets
   7 import requests
   8 from urllib.parse import parse_qs
   9 from flask import Flask, render_template, request, redirect, flash, url_for, jsonify, g
  10
  11 from common import *
  12
  13 app = Flask(__name__)
  14 app.secret_key = secrets.token_bytes(16) # XXX: generate and hard-code, or cookies and csrf-validation will fail!
  15
  16 @app.route('/')
  17 def index():
  18     return redirect(url_for('feed'), code=302)
  19
  20 @app.route('/feed/subscriptions')
  21 def feed():
  22     token = request.args.get('token', 'guest')
  23     page = int(request.args.get('page', 0))
  24     with sqlite3.connect(cf['global']['database']) as conn:
  25         c = conn.cursor()
  26         c.execute("""
  27            SELECT videos.id, channel_id, name, title, published, flags.display
  28              FROM videos
  29              JOIN channels ON videos.channel_id = channels.id
  30         LEFT JOIN flags ON (videos.id = flags.video_id) AND (flags.user = ?)
  31             WHERE channel_id IN
  32                   (SELECT channel_id FROM subscriptions WHERE user = ?)
  33                   AND flags.display IS NOT 'hidden'
  34          ORDER BY (display = 'pinned') DESC, crawled DESC
  35             LIMIT 36
  36            OFFSET 36*?""", (token, token, page))
  37         rows = [{
  38             'video_id': video_id,
  39             'channel_id': channel_id,
  40             'author': author,
  41             'title': title,
  42             'published': published,
  43             'pinned': display == 'pinned',
  44         } for (video_id, channel_id, author, title, published, display) in c.fetchall()]
  45     return render_template('index.html.j2', rows=rows, page=page)
  46
  47 @app.route('/watch')
  48 def watch():
  49     if not 'v' in request.args:
  50         return "missing video id", 400
  51
  52     plaintextheaders = {
  53         'content-type': 'text/plain',
  54         'Link': "<data:text/css,body%7Bcolor:%23eee;background:%23333%7D>; rel=stylesheet;"
  55     }
  56
  57     video_id = request.args.get('v')
  58     sts, algo = get_cipher()
  59     video_url, metadata, error, errdetails = get_video_info(video_id, sts, algo)
  60
  61     extra = {'geolocked':'local=1', 'livestream':'raw=0'}.get(error,'')
  62     invidious_url = f"https://invidio.us/watch?v={video_id}&{extra}&raw=1"
  63     errdetails = {
  64         'malformed':  "Video ID is invalid.",
  65         'geolocked':  "This video is geolocked.",
  66         'livestream': "Livestreams not yet supported.",
  67         'exhausted':  errdetails or "Couldn't extract video URLs.",
  68         'player':     errdetails,
  69     }.get(error)
  70
  71     show = request.args.get("show")
  72     if show == "raw":
  73         if error:
  74             msg = errdetails if error=='player' else f"{error.upper()}: {errdetails}"
  75             return f"{msg}\n\nRedirecting to Invidious.", 502, {
  76                 'Refresh': f'2; URL={invidious_url}',
  77                 **plaintextheaders}
  78         return redirect(video_url, code=307)
  79     elif show == "json":
  80         if error and not metadata:
  81             return {'error': True, error: errdetails}, 400 # TODO: better (test _CpR4o81XQc)
  82         return jsonify(metadata)
  83     else:
  84         if error and not metadata: # e.g. malformed, private/deleted video, ...
  85             return errdetails,400 # TODO: nicer
  86         return render_template('watch.html.j2',
  87             video_id=video_id, video_url=video_url,
  88             video_error=error, errdetails=errdetails, invidious_url=invidious_url,
  89             **prepare_metadata(metadata))
  90
  91 @app.route('/channel/<channel_id>')
  92 def channel(channel_id):
  93     if not re.match(r"(UC[A-Za-z0-9_-]{22})", channel_id):
  94         return "bad channel id", 400 # todo
  95
  96     xmlfeed = fetch_xml("channel_id", channel_id)
  97     if not xmlfeed:
  98         return "not found or something", 404 # XXX
  99     title, author, videos = parse_xml(xmlfeed)
 100     return render_template('xmlfeed.html.j2', title=author, rows=videos)
 101
 102 @app.route('/playlist')
 103 def playlist():
 104     playlist_id = request.args.get('list')
 105     if not playlist_id:
 106         return "bad list id", 400 # todo
 107
 108     xmlfeed = fetch_xml("playlist_id", playlist_id)
 109     if not xmlfeed:
 110         return "not found or something", 404 # XXX
 111     title, author, videos = parse_xml(xmlfeed)
 112     return render_template('xmlfeed.html.j2', title=f"{title} by {author}", rows=videos)
 113
 114 @app.route('/subscription_manager')
 115 def subscription_manager():
 116     token = request.args.get('token', 'guest')
 117     with sqlite3.connect(cf['global']['database']) as conn:
 118         #with conn.cursor() as c:
 119             c = conn.cursor()
 120             c.execute("""
 121                   SELECT subscriptions.channel_id, name,
 122                          (subscribed_until < datetime('now')) AS obsolete
 123                     FROM subscriptions
 124                     left JOIN channels ON channels.id = subscriptions.channel_id
 125                     left JOIN websub ON channels.id = websub.channel_id
 126                    WHERE user = ?
 127                 ORDER BY obsolete=0, name COLLATE NOCASE ASC""", (token,))
 128             rows = [{
 129                 'channel_id': channel_id,
 130                 'author': author or channel_id,
 131                 'subscribed_until': subscribed_until
 132             } for (channel_id, author, subscribed_until) in c.fetchall()]
 133     return render_template('subscription_manager.html.j2', rows=rows)
 134
 135 @app.route('/feed/subscriptions', methods=['POST'])
 136 def feed_post():
 137     token = request.args.get('token', 'guest')
 138     if token == 'guest': return "guest user is read-only", 403
 139     action = next(request.form.keys(), None)
 140     if action in ['pin', 'unpin', 'hide']:
 141         video_id = request.form.get(action)
 142         display = {
 143             'pin': 'pinned',
 144             'unpin': None,
 145             'hide': 'hidden',
 146         }[action]
 147         with sqlite3.connect(cf['global']['database']) as conn:
 148             #with conn.cursor() as c:
 149                 c = conn.cursor()
 150                 c.execute("""
 151                         INSERT OR REPLACE INTO flags (user, video_id, display)
 152                         VALUES (?, ?, ?)
 153                 """, (token, video_id, display))
 154     else:
 155         flash(("error","unsupported action"))
 156     return redirect(request.url, code=303)
 157
 158 @app.route('/subscription_manager', methods=['POST'])
 159 def manage_subscriptions():
 160     token = request.args.get('token', 'guest')
 161     if token == 'guest': return "guest user is read-only", 403
 162     if 'subscribe' in request.form:
 163         channel_id = request.form.get("subscribe")
 164         match = re.match(r"(UC[A-Za-z0-9_-]{22})", channel_id)
 165         if match:
 166             channel_id = match.group(1)
 167         else:
 168             match = re.match(r"((?:PL|LL|EC|UU|FL|UL|OL)[A-Za-z0-9_-]{10,})", channel_id)
 169             if match:  # NOTE: PL-playlists are 32chars, others differ in length.
 170                 flash(("error","playlists not (yet?) supported."))
 171                 return redirect(request.url, code=303) # TODO: dedup redirection
 172             else:
 173                 flash(("error","not a valid/subscribable URI"))
 174                 return redirect(request.url, code=303) # TODO: dedup redirection
 175         with sqlite3.connect(cf['global']['database']) as conn:
 176             #with conn.cursor() as c:
 177                 c = conn.cursor()
 178                 c.execute("""
 179                         INSERT OR IGNORE INTO subscriptions (user, channel_id)
 180                         VALUES (?, ?)
 181                 """, (token, channel_id))
 182                 # TODO: sql-error-handling, asynchronically calling update-subs.pl
 183
 184     elif 'unsubscribe' in request.form:
 185         with sqlite3.connect(cf['global']['database']) as conn:
 186             #with conn.cursor() as c:
 187                 c = conn.cursor()
 188                 c.execute("""
 189                         DELETE FROM subscriptions
 190                         WHERE user = ? AND channel_id = ?
 191                 """, (token, channel_id))
 192                 # TODO: sql-error-handling, report success
 193
 194     else:
 195         flash(("error","unsupported action"))
 196
 197     return redirect(request.url, code=303)
 198
 199 @app.route('/r/')
 200 def reddit_index():
 201     return ""
 202 @app.route('/r/<subreddit>')
 203 def reddit(subreddit="videos"):
 204     count = int(request.args.get('count', 0))
 205     before = request.args.get('before')
 206     after = request.args.get('after')
 207     query = '&'.join([f"{k}={v}" for k,v in [('count',count), ('before',before), ('after',after)] if v])
 208     r = requests.get(f"https://old.reddit.com/r/{subreddit}.json?{query}", headers={'User-Agent':'Mozilla/5.0'})
 209     if not r.ok or not 'data' in r.json():
 210         return r.text+"error retrieving reddit data", 502
 211
 212     good = [e for e in r.json()['data']['children'] if e['data']['score'] > 1]
 213     bad  = [e for e in r.json()['data']['children'] if e['data']['score'] <=1]
 214     videos = []
 215     for entry in (good+bad):
 216         e = entry['data']
 217         if e['domain'] not in ['youtube.com', 'youtu.be', 'invidio.us']:
 218             continue
 219         video_id = re.match(r'^https?://(?:www.|m.)?(?:youtube.com/watch\?(?:.*&amp;)?v=|youtu.be/|youtube.com/embed/)([-_0-9A-Za-z]+)', e['url']).group(1)
 220         if not video_id: continue
 221         videos.append({
 222             'video_id': video_id,
 223             'title': e['title'],
 224             'url': e['permalink'],
 225             'n_comments': e['num_comments'],
 226             'n_karma': e['score'],
 227         })
 228     before = r.json()['data']['before']
 229     after = r.json()['data']['after']
 230     return render_template('reddit.html.j2', subreddit=subreddit, rows=videos, before=before, after=after, count=count)
 231
 232 def get_cipher():
 233     # reload cipher from database every 1 hour
 234     if 'cipher' not in g or time.time() - g.get('cipher_updated', 0) > 1 * 60 * 60:
 235         with sqlite3.connect(cf['global']['database']) as conn:
 236             c = conn.cursor()
 237             c.execute("SELECT sts, algorithm FROM cipher")
 238             g.cipher = c.fetchone()
 239             g.cipher_updated = time.time()
 240
 241     return g.cipher
 242
 243 #@app.teardown_appcontext
 244 #def teardown_db():
 245 #    db = g.pop('db', None)
 246 #
 247 #    if db is not None:
 248 #        db.close()
 249
 250 # Magic CSRF protection: This modifies outgoing HTML responses and injects a csrf token into all forms.
 251 # All post requests are then checked if they contain the valid token.
 252 # TODO:
 253 # - don't use regex for injecting
 254 # - inject a http header into all responses (that could be used by apis)
 255 # - allow csrf token to be passed in http header, json, ...
 256 # - a decorator on routes to opt out of verification or output munging
 257 @app.after_request
 258 def add_csrf_protection(response):
 259     if response.mimetype == "text/html":
 260         token = hmac.new(app.secret_key, request.remote_addr.encode('ascii'), hashlib.sha256).hexdigest()  # TODO: will fail behind reverse proxy (remote_addr always localhost)
 261         response.set_data( re.sub(
 262             rb'''(<[Ff][Oo][Rr][Mm](\s+[a-zA-Z0-9-]+(=(\w*|'[^']*'|"[^"]*"))?)*>)''', # match form tags with any number of attributes and any type of quotes
 263             rb'\1<input type="hidden" name="csrf" value="'+token.encode('ascii')+rb'">', # hackily append a hidden input with our csrf protection value
 264             response.get_data()))
 265     return response
 266 @app.before_request
 267 def verify_csrf_protection():
 268     token = hmac.new(app.secret_key, request.remote_addr.encode('ascii'), hashlib.sha256).hexdigest()  # TODO: will fail behind reverse proxy (remote_addr always localhost)
 269     if request.method == "POST" and request.form.get('csrf') != token:
 270         return "CSRF validation failed!", 400
 271     request.form = request.form.copy() # make it mutable
 272     request.form.poplist('csrf')  # remove our csrf again
 273
 274 @app.template_filter('format_date')
 275 def format_date(s):
 276     (y,m,d) = (int(n) for n in s.split('T')[0].split(' ')[0].split('-'))  # iso-dates can seperate date from time with space or 'T'
 277     M = '_ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec'.split()
 278     return f"{d} {M[m]}"
 279
 280 if __name__ == '__main__':
 281     app.run(debug=True)