ical

This is an iCalendar rfc 5545 implementation in python. The goal of this project is to offer a calendar library that fills gaps in other widely used calendar libraries such as:

• Relevant and practical features needed for building a calendar application -- namely recurring events.
• Simple APIs that are straight forward to use
• High quality code base with high test coverage and regular releases.

ical's main focus is on simplicity. Internally, this library uses other existing data parsing libraries making it easy to support as much as possible of rfc5545. It is not a goal to support everything exhaustively (e.g. enterprise features), however, the simplicity of the implementation makes it easy to do so. The package has high coverage, and high test coverage, and is easy to extend with new rfc5545 properties.

This packages uses semantic versioning, and releases often, and works on recent python versions.

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

You may prefer these projects if you want something that changes less often or if you require a non-modern version of python and if you don't mind patching recurring events on top yourself e.g. using python-recurring-ical-events.