This is an iCalendar rfc 5545 implementation in python. The goal of this project is to offer a calendar library with the relevant and practical features needed for building a calendar application (e.g. recurring events).

ical's main focus is on simplicity, and the internal implementation is based on existing parsing libraries, where possible, making it easy to support as much as possible of rfc5545. It is not a goal to support everything exhaustively, however, the simplicity of the implementation makes it easy to do so.

See documentation for full quickstart and API reference.

Quickstart

The example below creates a Calendar, then adds an all day event to the calendar, then iterates over all events on the calendar.

from datetime import date

from ical.calendar import Calendar
from ical.event import Event

calendar = Calendar()
calendar.events.append(
    Event(summary="Event summary", start=date(2022, 7, 3), end=date(2022, 7, 4)),
)
for event in calendar.timeline:
    print(event.summary)

Reading ics files

This example parses an .ics file from disk and creates a ical.calendar.Calendar object, then prints out the events in order:

from pathlib import Path
from ical.calendar_stream import IcsCalendarStream
from ical.exceptions import CalendarParseError

filename = Path("example/calendar.ics")
with filename.open() as ics_file:
    try:
        calendar = IcsCalendarStream.calendar_from_ics(ics_file.read())
    except CalendarParseError as err:
        print(f"Failed to parse ics file '{str(filename)}': {err}")
    else:
        print([event.summary for event in calendar.timeline])

Writing ics files

This example writes a calendar object to an ics output file:

from pathlib import Path
from ical.calendar_stream import IcsCalendarStream

filename = Path("example/output.ics")
with filename.open() as ics_file:
    ics_file.write(IcsCalendarStream.calendar_to_ics(calendar))

Application-level APIs

The above APIs are used for lower level interaction with calendar components, however applications require a higher level interface to manage some of the underlying complexity. The ical.store library is used to manage state at a higher level (e.g. ensuring timezones are created properly) or handling edits to recurring events.

Recurring events

A calendar event may be recurring (e.g. weekly, monthly, etc). Recurring events are represented in a ical.calendar.Calendar with a single ical.event.Event object, however when observed through a ical.timeline.Timeline will be expanded based on the recurrence rule. See the rrule, rdate, and exdate fields on the ical.event.Event for more details.

Related Work

There are other python rfc5545 implementations that are more mature, and having been around for many years, are still active, and served as reference implementations for this project:

• Ics.py - github docs - Since 2013
• icalendar github docs - Since 2005