A telegram bot to receive a message when there is a new spot for tumi events
TODO:
- Make bot register yourself for events you want, sending notification to complete payment in case it is needed
At TUM we are in about 50 000 students and a great quantity are exchange or international students. The TUMI App is a pwa where students can register to events organized for international students, but there are usually few spots available. Events with even 300 spots can become fully booked in less than 10 minutes. This project consists in a telegram bot that sends you a message when a new event is published or when there is a new free spot in an event that was fully booked.
The bot has been developed by using Typescript and Node.js. Initially, it used a webscraper that used puppeteer; it worked but it was susceptible to the websites' changes and was not so performant. This is why a newer version was developerd that used directly the GraphQL api used by the tumi pwa. Redis has been used as database, Telegraf as bot library and Bull.js as a scheduler. The deploy has been done with Docker (swarms). The code is also linted with ESLint and Prettier.
It is quite simple:
- The telegram bot is started; it has the /start, /stop, /help, /author and /version commands.
- A scheduler is started by using bull.js
- Every time the scheduler fires, it gets the updated events, saves them on redis, checks if there are changes (new event id, change of an event's spots from 0 to a positive number, an event registration is now open or opens soon) and, if there are changes, sends a telegram message to all the registered users.
- Every time a user starts or stops the bot, it is added or removed to the redis database, so that the bot knows to whom send the messages.
There is a Dockerfile that is used to create an image of the bot, that is automatically published on DockerHub through a Github Action. In the deploy folder, there is the docker-compose.yml file that is used by docker swarm to serve the bot, the redis db and the watchtower updater.