Mensa Uni Halle Telegram Bot

A bot to display the canteen menu via a telegram bot

Telegram Bot Api

https://core.telegram.org/bots

How it works

It uses the nice telegram bot js framework telegraf.js https://github.com/telegraf/telegraf

To get the actual menu data it uses axios https://github.com/axios/axios to make the request and get the html of the menu site

Then the html is parsed via xmldom https://github.com/jindw/xmldom and post-processed via html-entities https://github.com/mdevils/node-html-entities (to get the € to €)

After that we have a dom and can use xpath https://github.com/goto100/xpath to execute xpath on that dom
However I needed to change xpath because it was not working (took me quite some time to recognize this) with the html dom created by xmldom, see https://github.com/janisdd/xpath for changes

To store the days to add a plain js object is used (see inMemorySessionStorage.ts)

Command list

m - gibt das Menü von heute zurück
m1 - gibt das Menü von morgen zurück
m2 - gibt das Menü in 2 Tagen zurück
m3 - gibt das Menü in 3 Tagen zurück
abbrechen - bricht einen der /m Befehle ab
about - zeigt about daten an
help - zeigt die Hilfe an

To add this to the bot

goto botfather
/setcommands

and enter the above list

a hidden command is

/chatid - returns the chat id for debugging

Project structure

constants - some constants
enums - important values (canteens)
helper - some helpers
inMemorySessionStorage - used to store data per chat & user
main - main entry point, bot with commands is set up here
mensaDataHelper - helper for canteen data related stuff (http request and xpath are done here)
types - some global types
- other types are kept close to where they are used

Run locally

You need to have the typescript compiler (tsc) installed globally

then do

tsc

this will compile and watch the files for changes

run the main file

node dist/main.js

to deploy you want to make config.json only accessible to the running user... (botToken should be only known to you!)

Some notes