screen-calendar-get.py

from datetime import datetime, date, timedelta
from time import time
from tzlocal import get_localzone
import locale
import os.path
import os
import sys
import codecs
import caldav
import vobject
import logging

locale.setlocale(locale.LC_TIME, os.getenv('LC_TIME',''))
localzone = get_localzone()

# normalize dates, otherwise we can't compare them
def byStartDate(event):
    d = dn = event.dtstart.value
    if (type(dn).__name__ == 'date'):
        dn = datetime.combine(dn, datetime.min.time())
    if (dn.tzinfo is None or dn.tzinfo.utcoffset(dn) is None):
        dn = localzone.localize(dn)
    # print (d, '-->', dn)
    return dn

user = os.getenv('APPLE_CAL_USER', '')
passwd = os.getenv('APPLE_CAL_PASSWORD', '')
if user == '' or passwd == '' :
    print('APPLE_CAL_USER or APPLE_CAL_PASSWORD is missing')
    sys.exit(1)

template = 'screen-output-weather.svg'
stale = True
calDavServer = 'https://caldav.icloud.com/'
weeksToSearch = 6
resultCal = None

if (os.path.isfile(os.getcwd() + '/calendar.cal')):
    print('Found cached calendar response')
    with open('calendar.cal', 'r') as cal:
        resultCal = vobject.readOne(cal)
    stale=time() - os.path.getmtime(os.getcwd() + '/calendar.cal') > (1*60*60)

if stale:
    print('Calender data is stale, calling', calDavServer)
    try:
        client = caldav.DAVClient(calDavServer, username=user, password=passwd)
        principal = client.principal()
        start = datetime.utcnow()
        resultCal = vobject.iCalendar()
        for calendar in principal.calendars():
            events = calendar.date_search(
                start=start,
                end=(start + timedelta(weeks=weeksToSearch)),
                expand=True)  # expands recurring events to their _next_ occurrence
            for comp in events:
                vevent = comp.vobject_instance.vevent
                # Expanded recurring events contain 2 DTSTAMP lines, which is illegal,
                # leading to errors on .serialize(). Fix is to remove one such line (or all?)
                vevent.remove(vevent.dtstamp)
                resultCal.add(vevent)
            with open('calendar.cal', 'w') as cal:
                cal.write(resultCal.serialize())
    except Exception as e:
        logging.exception(e)
        print('Failed to get new API response, will use older response')
        with open('calendar.cal', 'r') as cal:
            resultCal = vobject.readOne(cal)

if not resultCal:
    print('No upcoming events found.')

events = []
for comp in resultCal.components():
    if (comp.name == 'VEVENT'):
        events.append(comp)

events.sort(key=byStartDate)

output = codecs.open(template , 'r', encoding='utf-8').read()
i = 0
while (i < 3): # we have 3 slots in the UI
    day=desc=''
    if (i < len(events)):
        desc = events[i].summary.value
        start = events[i].dtstart.value
        end = events[i].dtend.value
        if (type(start).__name__ == 'date' and type(end).__name__ == 'date'):  # date (whole day event)
            day = start.strftime('%a %-d.%-m.')
            if (abs(start - end).days > 1): # show end date for multi-day events
                day = day + end.strftime(' – %a %-d.%-m.')
        else: # event with time, i.e. within a day
            day = start.strftime('%a %-d.%-m. %H:%M')
        print(day, desc)
    output = output.replace('CAL_'+str(i), day)
    output = output.replace('CAL_DESC_'+str(i), desc)
    i = i + 1

codecs.open('screen-output-weather.svg', 'w', encoding='utf-8').write(output)