app/frontend.py

   1 import re
   2 import time
   3 import hmac
   4 import base64
   5 import hashlib
   6 import sqlite3
   7 import secrets
   8 import requests
   9 from urllib.parse import parse_qs
  10 from werkzeug.security import generate_password_hash, check_password_hash
  11 from flask import Flask, render_template, request, redirect, flash, url_for, jsonify, g
  12 from flask_login import LoginManager, UserMixin, current_user, login_user, logout_user, login_required
  13
  14 from common import *
  15
  16 app = Flask(__name__)
  17 if 'secret_key' in cf['frontend']:
  18     app.secret_key = base64.b64decode(cf['frontend']['secret_key'])
  19 else:
  20     app.secret_key = secrets.token_bytes(16)
  21 login = LoginManager(app)
  22 login.login_view = 'login_form'
  23
  24 @app.route('/')
  25 def index():
  26     return redirect(url_for('feed'), code=302)
  27
  28 @app.route('/feed/subscriptions')
  29 @login_required
  30 def feed():
  31     token = current_user.token # request.args.get('token', 'guest')
  32     page = int(request.args.get('page', 0))
  33     with sqlite3.connect(cf['global']['database']) as conn:
  34         c = conn.cursor()
  35         c.execute("""
  36            SELECT videos.id, channel_id, name, title, published, flags.display
  37              FROM videos
  38              JOIN channels ON videos.channel_id = channels.id
  39         LEFT JOIN flags ON (videos.id = flags.video_id) AND (flags.user = ?)
  40             WHERE channel_id IN
  41                   (SELECT channel_id FROM subscriptions WHERE user = ?)
  42                   AND flags.display IS NOT 'hidden'
  43          ORDER BY (display = 'pinned') DESC, crawled DESC
  44             LIMIT 36
  45            OFFSET 36*?""", (token, token, page))
  46         rows = [{
  47             'video_id': video_id,
  48             'channel_id': channel_id,
  49             'author': author,
  50             'title': title,
  51             'published': published,
  52             'pinned': display == 'pinned',
  53         } for (video_id, channel_id, author, title, published, display) in c.fetchall()]
  54     return render_template('index.html.j2', rows=rows, page=page)
  55
  56 @app.route('/watch')
  57 def watch():
  58     if not 'v' in request.args:
  59         return "missing video id", 400
  60
  61     plaintextheaders = {
  62         'content-type': 'text/plain',
  63         'Link': "<data:text/css,body%7Bcolor:%23eee;background:%23333%7D>; rel=stylesheet;"
  64     }
  65
  66     video_id = request.args.get('v')
  67     sts, algo = get_cipher()
  68     video_url, metadata, error, errdetails = get_video_info(video_id, sts, algo)
  69
  70     extra = {'geolocked':'local=1', 'livestream':'raw=0'}.get(error,'')
  71     invidious_url = f"https://invidio.us/watch?v={video_id}&{extra}&raw=1"
  72     errdetails = {
  73         'malformed':  "Video ID is invalid.",
  74         'geolocked':  "This video is geolocked.",
  75         'livestream': "Livestreams not yet supported.",
  76         'exhausted':  errdetails or "Couldn't extract video URLs.",
  77         'player':     errdetails,
  78     }.get(error)
  79
  80     show = request.args.get("show")
  81     if show == "raw":
  82         if error:
  83             msg = errdetails if error=='player' else f"{error.upper()}: {errdetails}"
  84             return f"{msg}\n\nRedirecting to Invidious.", 502, {
  85                 'Refresh': f'2; URL={invidious_url}',
  86                 **plaintextheaders}
  87         return redirect(video_url, code=307)
  88     elif show == "json":
  89         if error and not metadata:
  90             return {'error': True, error: errdetails}, 400 # TODO: better (test _CpR4o81XQc)
  91         return jsonify(metadata)
  92     else:
  93         if error and not metadata: # e.g. malformed, private/deleted video, ...
  94             return errdetails,400 # TODO: nicer
  95         return render_template('watch.html.j2',
  96             video_id=video_id, video_url=video_url,
  97             video_error=error, errdetails=errdetails, invidious_url=invidious_url,
  98             **prepare_metadata(metadata))
  99
 100 @app.route('/channel/<channel_id>')
 101 def channel(channel_id):
 102     if not re.match(r"(UC[A-Za-z0-9_-]{22})", channel_id):
 103         return "bad channel id", 400 # todo
 104
 105     xmlfeed = fetch_xml("channel_id", channel_id)
 106     if not xmlfeed:
 107         return "not found or something", 404 # XXX
 108     title, author, videos = parse_xml(xmlfeed)
 109     return render_template('xmlfeed.html.j2', title=author, rows=videos)
 110
 111 @app.route('/playlist')
 112 def playlist():
 113     playlist_id = request.args.get('list')
 114     if not playlist_id:
 115         return "bad list id", 400 # todo
 116
 117     xmlfeed = fetch_xml("playlist_id", playlist_id)
 118     if not xmlfeed:
 119         return "not found or something", 404 # XXX
 120     title, author, videos = parse_xml(xmlfeed)
 121     return render_template('xmlfeed.html.j2', title=f"{title} by {author}", rows=videos)
 122
 123 @app.route('/subscription_manager')
 124 def subscription_manager():
 125     token = request.args.get('token', 'guest')
 126     with sqlite3.connect(cf['global']['database']) as conn:
 127         #with conn.cursor() as c:
 128             c = conn.cursor()
 129             c.execute("""
 130                   SELECT subscriptions.channel_id, name,
 131                          (subscribed_until < datetime('now')) AS obsolete
 132                     FROM subscriptions
 133                     left JOIN channels ON channels.id = subscriptions.channel_id
 134                     left JOIN websub ON channels.id = websub.channel_id
 135                    WHERE user = ?
 136                 ORDER BY obsolete=0, name COLLATE NOCASE ASC""", (token,))
 137             rows = [{
 138                 'channel_id': channel_id,
 139                 'author': author or channel_id,
 140                 'subscribed_until': subscribed_until
 141             } for (channel_id, author, subscribed_until) in c.fetchall()]
 142     return render_template('subscription_manager.html.j2', rows=rows)
 143
 144 @app.route('/feed/subscriptions', methods=['POST'])
 145 def feed_post():
 146     token = request.args.get('token', 'guest')
 147     if token == 'guest': return "guest user is read-only", 403
 148     action = next(request.form.keys(), None)
 149     if action in ['pin', 'unpin', 'hide']:
 150         video_id = request.form.get(action)
 151         display = {
 152             'pin': 'pinned',
 153             'unpin': None,
 154             'hide': 'hidden',
 155         }[action]
 156         with sqlite3.connect(cf['global']['database']) as conn:
 157             #with conn.cursor() as c:
 158                 c = conn.cursor()
 159                 c.execute("""
 160                         INSERT OR REPLACE INTO flags (user, video_id, display)
 161                         VALUES (?, ?, ?)
 162                 """, (token, video_id, display))
 163     else:
 164         flash("unsupported action", "error")
 165     return redirect(request.url, code=303)
 166
 167 @app.route('/subscription_manager', methods=['POST'])
 168 def manage_subscriptions():
 169     token = request.args.get('token', 'guest')
 170     if token == 'guest': return "guest user is read-only", 403
 171     if 'subscribe' in request.form:
 172         channel_id = request.form.get("subscribe")
 173         match = re.match(r"(UC[A-Za-z0-9_-]{22})", channel_id)
 174         if match:
 175             channel_id = match.group(1)
 176         else:
 177             match = re.match(r"((?:PL|LL|EC|UU|FL|UL|OL)[A-Za-z0-9_-]{10,})", channel_id)
 178             if match:  # NOTE: PL-playlists are 32chars, others differ in length.
 179                 flash("playlists not (yet?) supported.", "error")
 180                 return redirect(request.url, code=303) # TODO: dedup redirection
 181             else:
 182                 flash("not a valid/subscribable URI", "error")
 183                 return redirect(request.url, code=303) # TODO: dedup redirection
 184         with sqlite3.connect(cf['global']['database']) as conn:
 185             #with conn.cursor() as c:
 186                 c = conn.cursor()
 187                 c.execute("""
 188                         INSERT OR IGNORE INTO subscriptions (user, channel_id)
 189                         VALUES (?, ?)
 190                 """, (token, channel_id))
 191                 # TODO: sql-error-handling, asynchronically calling update-subs.pl
 192
 193     elif 'unsubscribe' in request.form:
 194         with sqlite3.connect(cf['global']['database']) as conn:
 195             #with conn.cursor() as c:
 196                 c = conn.cursor()
 197                 c.execute("""
 198                         DELETE FROM subscriptions
 199                         WHERE user = ? AND channel_id = ?
 200                 """, (token, channel_id))
 201                 # TODO: sql-error-handling, report success
 202
 203     else:
 204         flash("unsupported action", "error")
 205
 206     return redirect(request.url, code=303)
 207
 208 @app.route('/r/')
 209 def reddit_index():
 210     return ""
 211 @app.route('/r/<subreddit>')
 212 def reddit(subreddit="videos"):
 213     count = int(request.args.get('count', 0))
 214     before = request.args.get('before')
 215     after = request.args.get('after')
 216     query = '&'.join([f"{k}={v}" for k,v in [('count',count), ('before',before), ('after',after)] if v])
 217     r = requests.get(f"https://old.reddit.com/r/{subreddit}.json?{query}", headers={'User-Agent':'Mozilla/5.0'})
 218     if not r.ok or not 'data' in r.json():
 219         return r.text+"error retrieving reddit data", 502
 220
 221     good = [e for e in r.json()['data']['children'] if e['data']['score'] > 1]
 222     bad  = [e for e in r.json()['data']['children'] if e['data']['score'] <=1]
 223     videos = []
 224     for entry in (good+bad):
 225         e = entry['data']
 226         if e['domain'] not in ['youtube.com', 'youtu.be', 'invidio.us']:
 227             continue
 228         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)
 229         if not video_id: continue
 230         videos.append({
 231             'video_id': video_id,
 232             'title': e['title'],
 233             'url': e['permalink'],
 234             'n_comments': e['num_comments'],
 235             'n_karma': e['score'],
 236         })
 237     before = r.json()['data']['before']
 238     after = r.json()['data']['after']
 239     return render_template('reddit.html.j2', subreddit=subreddit, rows=videos, before=before, after=after, count=count)
 240
 241 @app.route('/login')
 242 def login_form():
 243     if current_user.is_authenticated:
 244         return """
 245 <body bgcolor="#333" text="#ccc" link="#aaa">
 246 <form action="/logout" method=POST>
 247 <input type=submit value="log out">
 248 </form>
 249         """
 250     else:
 251         return """
 252 <body bgcolor="#333" text="#ccc" link="#aaa">
 253 <form method=POST>
 254 <label>User:<input name=user></label><br>
 255 <label>Password:<input name=password></label><br>
 256 <button name=action value="login">log in</button>
 257 <button name=action value="register">sign up</button>
 258 </form>
 259         """
 260 @app.route('/logout', methods=['POST'])
 261 def do_logout():
 262     logout_user()
 263     return redirect(url_for('index'))
 264
 265 @app.route('/login', methods=['POST'])
 266 def do_login():
 267     user = User.from_name(request.form.get('user'))
 268     if user and user.check_password(request.form.get('password')):
 269         login_user(user, remember=request.form.get('remember',False))
 270         return redirect(url_for('index'))
 271     flash('wrong username and/or password', 'error')
 272     return redirect(url_for('login_form'))
 273
 274 def get_cipher():
 275     # reload cipher from database every 1 hour
 276     if 'cipher' not in g or time.time() - g.get('cipher_updated', 0) > 1 * 60 * 60:
 277         with sqlite3.connect(cf['global']['database']) as conn:
 278             c = conn.cursor()
 279             c.execute("SELECT sts, algorithm FROM cipher")
 280             g.cipher = c.fetchone()
 281             g.cipher_updated = time.time()
 282
 283     return g.cipher
 284
 285 class User(UserMixin):
 286     def __init__(self, id, name, passwd, token):
 287         self.id = id
 288         self.name = name
 289         self.passwd = passwd
 290         self.token = token
 291     def set_password(self, passwd):
 292         self.passwd = generate_password_hash(passwd)
 293         # ^TODO: store changes to database
 294     def check_password(self, passwd):
 295         return check_password_hash(self.passwd, passwd)
 296     @classmethod
 297     def from_id(self, id):
 298         with sqlite3.connect(cf['global']['database']) as conn:
 299             c = conn.cursor()
 300             c.execute("SELECT name,password,token FROM users WHERE id = ?", (id,))
 301             name, passwd, token = c.fetchone()
 302             return User(id, name, passwd, token)
 303             # ^TODO: not found
 304     @classmethod
 305     def from_name(self, name):
 306         with sqlite3.connect(cf['global']['database']) as conn:
 307             c = conn.cursor()
 308             c.execute("SELECT id,password,token FROM users WHERE name=?", (name,))
 309             id, passwd, token = c.fetchone()
 310             return User(id, name, passwd, token)
 311             # ^TODO: not found
 312
 313 @login.user_loader
 314 def load_user(id):
 315     return User.from_id(int(id))
 316
 317 #@app.teardown_appcontext
 318 #def teardown_db():
 319 #    db = g.pop('db', None)
 320 #
 321 #    if db is not None:
 322 #        db.close()
 323
 324 # Magic CSRF protection: This modifies outgoing HTML responses and injects a csrf token into all forms.
 325 # All post requests are then checked if they contain the valid token.
 326 # TODO:
 327 # - don't use regex for injecting
 328 # - inject a http header into all responses (that could be used by apis)
 329 # - allow csrf token to be passed in http header, json, ...
 330 # - a decorator on routes to opt out of verification or output munging
 331 @app.after_request
 332 def add_csrf_protection(response):
 333     if response.mimetype == "text/html":
 334         token = hmac.new(app.secret_key, request.remote_addr.encode('ascii'), hashlib.sha256).hexdigest()  # TODO: will fail behind reverse proxy (remote_addr always localhost)
 335         response.set_data( re.sub(
 336             rb'''(<[Ff][Oo][Rr][Mm](\s+[a-zA-Z0-9-]+(=(\w*|'[^']*'|"[^"]*"))?)*>)''', # match form tags with any number of attributes and any type of quotes
 337             rb'\1<input type="hidden" name="csrf" value="'+token.encode('ascii')+rb'">', # hackily append a hidden input with our csrf protection value
 338             response.get_data()))
 339     return response
 340 @app.before_request
 341 def verify_csrf_protection():
 342     token = hmac.new(app.secret_key, request.remote_addr.encode('ascii'), hashlib.sha256).hexdigest()  # TODO: will fail behind reverse proxy (remote_addr always localhost)
 343     if request.method == "POST" and request.form.get('csrf') != token:
 344         return "CSRF validation failed!", 400
 345     request.form = request.form.copy() # make it mutable
 346     request.form.poplist('csrf')  # remove our csrf again
 347
 348 @app.template_filter('format_date')
 349 def format_date(s):
 350     (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'
 351     M = '_ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec'.split()
 352     return f"{d} {M[m]}"
 353
 354 if __name__ == '__main__':
 355     app.run(debug=True)