app/webhooks.py

   1 """
   2 This is the webhook server that interfaces with Google's WebSub (formerly pubsubhubbub) server. This is its own server, so it can live on a different host than the frontend.
   3 """
   4
   5 #TODO: fold update-websub.py into this?
   6
   7 import time
   8 import sqlite3
   9 from flask import Flask, request
  10 from urllib.parse import parse_qs, urlparse
  11
  12 from common.common import *
  13
  14 app = Flask(__name__)
  15
  16 @app.route('/websub/v1/<int:timestamp>/<nonce>/<subject>/<sig>', methods=["GET"])
  17 def websub(timestamp, nonce, subject, sig):
  18     hmackey = cf['websub']['hmac_key']
  19     mode = request.args.get('hub.mode', '')
  20     topic = request.args.get('hub.topic', '')
  21     challenge = request.args.get('hub.challenge', '')
  22     until = int(request.args.get('hub.lease_seconds', '0'))
  23
  24     if sig != websub_url_hmac(hmackey, subject, timestamp, nonce):
  25         return '', 400
  26
  27     if time.time() - timestamp > int(cf['websub']['lease']):
  28         return '', 400
  29
  30     if mode != "subscribe":
  31         return '', 200
  32         # Note: channels are not purged from the websub dbtable.
  33
  34     with sqlite3.connect(cf['global']['database']) as conn:
  35         c = conn.cursor()
  36         c.execute("""
  37                 INSERT OR REPLACE INTO websub (channel_id, subscribed_until)
  38                            VALUES (?, datetime(?, 'unixepoch'))
  39         """, (subject, time.time()+until))
  40     return challenge, 200
  41
  42 @app.route('/websub/v1/<int:timestamp>/<nonce>/<subject>/<sig>', methods=["POST"])
  43 def websub_post(timestamp, nonce, subject, sig):
  44     lease = cf['websub']['lease']
  45     hmackey = cf['websub']['hmac_key']
  46     hub_signature = request.headers.get('X-Hub-Signature').replace("sha1=", "")
  47
  48     if sig != websub_url_hmac(hmackey, subject, timestamp, nonce):
  49         return '', 400
  50     if hub_signature != websub_body_hmac(hmackey, request.data):
  51         return '', 400
  52
  53     with sqlite3.connect(cf['global']['database']) as conn:
  54         c = conn.cursor()
  55         try:
  56             update_channel(conn, request.data, from_webhook=True)
  57         except Exception as e:
  58             app.logger.error(e)
  59             with open('/tmp/websub-subscriptions.err', 'ab') as f:
  60                 #data = request.data.decode("utf-8", errors="ignore")
  61                 f.write(f"<!-- {time.ctime()} ({int(time.time())}) -->\n".encode('ascii'))
  62                 f.write(request.data + b"\n")
  63     return '', 200
  64
  65 if __name__ == '__main__':
  66     app.run(debug=True)