iCalendar via Flask

flask_cal.py

from flask import Flask, send_file, make_response, jsonify
from icalendar import Calendar, Event
from datetime import datetime, timedelta
from pytz import UTC
import atexit
import json
import os

import tasks


app = Flask(__name__)


cache = {}


@app.route("/")
def index():
    return "dashboard"

@app.route("/tasks")
def get_tasks():
    return json.dumps(cache["tasks"], default=lambda o: o.__dict__, sort_keys=True, indent=4)

@app.route("/calendar")
def get_calendar():
    cal = Calendar()
    cal.add("prodid", "-//test//")
    cal.add("version", "2.0")

    for t in list(filter(lambda x: x.due is not None, cache["tasks"])):
        dt = datetime.strptime(t.due, "%Y-%m-%dT%H:%M:%SZ")

        event = Event()
        event.add("summary", t["title"])
        event.add("dtstart", dt.date())
        event.add("dtend", dt.date() + timedelta(days=1))
        event.add("dtstamp", datetime.now(tz=UTC))
        event.add("priority", 5)
        cal.add_component(event)

    response = make_response(cal.to_ical())
    response.headers["Content-Disposition"] = "attachment; filename=calendar.ics"
    return response

@atexit.register
def quit_server():
    print("Writing tasks to file...")
    tasks.write_tasks(cache["tasks"])

def main():
    cache["tasks"] = tasks.load_tasks()
    app.run(debug=True)


if __name__ == "__main__":
    main()