Moodle Telegram Notifier

moodle_telegram_notifier.py

"""
    Telegram Moodle Notificatior
    Get notifications for moodle events via telegram.
"""
import sys
from datetime import datetime, timedelta, date
import requests
import icalendar
import validators
from dateutil.rrule import *
from requests.auth import HTTPBasicAuth
import json
import requests

import config

TG_BOT_TOKEN = "" # Bot token you get from @botfather
TG_CHAT_ID = "-100" # Chat ID of a chat that the bot can write into
MOODLE_URL = "" # Your Moodle Calendar URL, exported from e.g. https://moodle.your-domain.de/calendar/export.php?

def send(bot_message):
    """ Send telegram message to chat """
    send_text = f"https://api.telegram.org/bot{TG_BOT_TOKEN}/sendMessage?chat_id={TG_CHAT_ID}&disable_web_page_preview=True&parse_mode=Markdown&text={bot_message}"
    response = requests.get(send_text)
    return response.json()


def verify_url(url):
    """ Verify a calendar URL """
    return validators.url(url)

def decode_component(component, component_name):
    """ Decode a calendar component """
    try:
        return component.decoded(component_name)
    except KeyError:
        return None

def check_event(component):
    """ Check if component is a real event """
    items = component.property_items()
    if len(items) > 0 and len(items[0]) > 0:
        return items[0][1] == b'VEVENT'
    return False

def extract_categories(lines):
    """ Extract categories from the component manually """
    for line in lines:
        if "CATEGORIES:" in line:
            return line.split("CATEGORIES:")[1]

def decode_event(component):
    """ Decode entities of a component """
    event = {}
    event["summary"] = decode_component(component,"SUMMARY").decode().strip()
    event["categories"] = extract_categories(component.content_lines()).strip()
    event["date"] = decode_component(component, "DTEND").replace(tzinfo=None)+ timedelta(hours=2)
    event["date_string"] = event["date"].strftime("%H:%M")    
    try:
        event["uid"] = decode_component(component,"UID").decode()
    except Exception:
        event["uid"] = event["summary"]+event["categories"]

    return event

def download_ical(url):
    """ Download a calendar file from URL """
    if not verify_url(url):
        print("invalid ical url")
        return False
    try:
        response = requests.get(url, allow_redirects=True)
        gcal = icalendar.Calendar.from_ical(response.content)
        return gcal
    except Exception as exception:
        print(exception)
        return False

# load json about already send messages
try:
    with open('moodle_uids.json') as json_file:
        send_icals = json.load(json_file)
except Exception:
    send_icals = []

# download calendar file
ical_calendar = download_ical(MOODLE_URL)
if not ical_calendar:
    print("error")
    sys.exit(0)

# check all calendar events
for component in ical_calendar.walk():
    # only check real events
    if check_event(component):
        # get event details into array
        event = decode_event(component)

        # check if event is tomorrow and not already send
        today = date.today()
        tomorrow = date.today() + timedelta(days=1)
        if not event["uid"] in send_icals and event["date"].date() == tomorrow:
            # create message string with markdown
            string = f"*Termin Morgen {event['date_string']} Uhr:*\r\n\r\n{event['categories']}\r\n➡️ *{event['summary']}*"
            # send telegram message
            print(send(string))
            # save event uid
            send_icals.append(event["uid"])

# save send message to file
with open('moodle_uids.json', 'w') as outfile:
    json.dump(send_icals, outfile)