Hacking course registration with Twilio and Python

scraper.py

import time

import requests
from bs4 import BeautifulSoup
from twilio.rest import Client
import redis

from secrets import twilio_account_sid, token, my_number

client = Client(twilio_account_sid, token)
redis_client = redis.StrictRedis(host='localhost', port=6379, db=0)

COURSE_NUM_NDX = 0
SEATS_NDX = 1


def message(recipient, body):
    message = client.messages.create(to=recipient, from_=my_number, body=body)


def get_open_seats():
    r = requests.get('http://courses.project.samueltaylor.org/')
    soup = BeautifulSoup(r.text, 'html.parser')
    courses = {}

    for row in soup.find_all('tr'):
        cols = [e.text for e in row.find_all('td')]
        if cols:
            courses[cols[COURSE_NUM_NDX]] = int(cols[SEATS_NDX])

    return courses


if __name__ == '__main__':
    courses = get_open_seats()
    for course, seats in courses.items():
        if seats == 0:
            continue

        to_notify = redis_client.smembers(course)
        for user in to_notify:
            message(user.decode('utf-8'), body=f"Good news! Spots opened up in {course}. We'll stop bugging you about "
                                                "this one now.")
            redis_client.srem(course, user)

secrets.py

twilio_account_sid = 'ACXXXXX'
my_number = '+1XXXXXXXXXX'
token = ''

sms_handler.py

from flask import Flask, request
from twilio.twiml.messaging_response import MessagingResponse
import redis

from secrets import my_number, twilio_account_sid

app = Flask(__name__)

valid_courses = {'CS 101', 'CS 201'}


def respond(user, body):
    response = MessagingResponse()
    response.message(to=user, from_=my_number, body=body)
    return str(response)

  
@app.route('/sms', methods=['POST'])
def handle_sms():
    redis_client = redis.StrictRedis(host='localhost', port=6379, db=0)
    if request.form['AccountSid'] != twilio_account_sid:
        return '', 400

    user = request.form['From']
    course = request.form['Body'].strip().upper() 
    if course not in valid_courses:
        return respond(user, body="Hm, that doesn't look like a valid course")

    redis_client.sadd(course, user.encode('utf-8'))
    return respond(user, body=f"Sweet action! We'll let you know when seats are available in {course}")

  
if __name__ == '__main__':
    app.run(debug=True)