vTimezone Europe/Berlin

README.md

tzdb.txt

The rule definition in the Olson database. A tool called zic parses these rules, instantiates all individual transitions in a given timeframe and then stores these instances in a binary format that ships with most UNIXes and the python zoneinfo module. All clients just parse those binary files with the specific transition dates, which do not contain any 'meta' information about the rules behind the transition dates.

zoneinfo.txt

The data I was able to extract from zoneinfo instances, as long as the plain-python implementation was used instead of the C-module.

apple-ccs-pycalendar-zonal.ics

Generated by Cyrus Daboo's / Apple's ccs-pycalendar tzconvert.py. The database directory of ics vTimezone files is used like this:

from pycalendar.icalendar.calendar import Calendar
from pycalendar.timezonedb import TimezoneDatabase
cal = TimezoneDatabase.getTimezoneInCalendar("Europe/Berlin")
with open("apple-ccs-pycalendar-none.ics", "wt") as f:
	cal.generate(f, includeTimezones=Calendar.NO_TIMEZONES)
with open("apple-ccs-pycalendar-all.ics", "wt") as f:
	cal.generate(f, includeTimezones=Calendar.ALL_TIMEZONES)

python-icalendar(-khal).ics

The python icalendar module seems to be unable to generate vTimezones, but the khal calendar cli seems to add a converter from pytz.

from icalendar import Calendar, Event
from datetime import datetime
import pytz
cal = Calendar()
cal.add('prodid', '-//My calendar product//mxm.dk//')
cal.add('version', '2.0')
event = Event()
event.add('summary', 'Test')
event.add('dtstart', datetime(2021, 2, 7, 12, 0, 0, tzinfo=pytz.timezone("Europe/Berlin")))
event.add('dtend',   datetime(2021, 2, 7, 13, 0, 0, tzinfo=pytz.timezone("Europe/Berlin")))
event.add('dtstamp', datetime(2021, 2, 7, 11, 0, 0, tzinfo=pytz.utc))
cal.add_component(event)
with open("python-icalendar.ics", "wb") as f:
	f.write(cal.to_ical())

from khal.khalendar.event import create_timezone
cal.add_component(create_timezone(pytz.timezone("Europe/Berlin")))
with open("python-icalendar-khal.ics", "wb") as f:
	f.write(cal.to_ical())

python-vobject.ics

import vobject
import pytz
cal = vobject.iCalendar()
vevent = cal.add('vevent')
vevent.add('summary').value = "Test"
vevent.add('dtstart').value = datetime(2021, 2, 7, 12, 0, 0, tzinfo=pytz.timezone("Europe/Berlin"))
vevent.add('dtend').value =   datetime(2021, 2, 7, 13, 0, 0, tzinfo=pytz.timezone("Europe/Berlin"))
vevent.add('dtstamp').value = datetime(2021, 2, 7, 11, 0, 0, tzinfo=pytz.utc)
with open("python-vobject.ics", "wt") as f:
	f.write(cal.serialize())

tzurl(-outlook).ics

tzurl is hosting two versions of files generated by a slightly modified vzic. Their python version of the tools seems to be non-functional.

vzic.ics

The vzic generated files included in ics_vtimezones.