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