Parsing files (ics/ icalendar) using Python

Question

I have a .ics file in the following format. What is the best way to parse it? I need to retrieve the Summary, Description, and Time for each of the entries.

BEGIN:VCALENDAR
X-LOTUS-CHARSET:UTF-8
VERSION:2.0
PRODID:-//Lotus Development Corporation//NONSGML Notes 8.0//EN
METHOD:PUBLISH
BEGIN:VTIMEZONE
TZID:India
BEGIN:STANDARD
DTSTART:19500101T020000
TZOFFSETFROM:+0530
TZOFFSETTO:+0530
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID="India":20100615T111500
DTEND;TZID="India":20100615T121500
TRANSP:OPAQUE
DTSTAMP:20100713T071035Z
CLASS:PUBLIC
DESCRIPTION:Emails\nDarlene\n Murphy\nDr. Ferri\n

UID:12D3901F0AD9E83E65257743001F2C9A-Lotus_Notes_Generated
X-LOTUS-UPDATE-SEQ:1
X-LOTUS-UPDATE-WISL:$S:1;$L:1;$B:1;$R:1;$E:1;$W:1;$O:1;$M:1
X-LOTUS-NOTESVERSION:2
X-LOTUS-APPTTYPE:0
X-LOTUS-CHILD_UID:12D3901F0AD9E83E65257743001F2C9A
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID="India":20100628T130000
DTEND;TZID="India":20100628T133000
TRANSP:OPAQUE
DTSTAMP:20100628T055408Z
CLASS:PUBLIC
DESCRIPTION:
SUMMARY:smart energy management
LOCATION:8778/92050462
UID:07F96A3F1C9547366525775000203D96-Lotus_Notes_Generated
X-LOTUS-UPDATE-SEQ:1
X-LOTUS-UPDATE-WISL:$S:1;$L:1;$B:1;$R:1;$E:1;$W:1;$O:1;$M:1
X-LOTUS-NOTESVERSION:2
X-LOTUS-NOTICETYPE:A
X-LOTUS-APPTTYPE:3
X-LOTUS-CHILD_UID:07F96A3F1C9547366525775000203D96
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID="India":20100629T110000
DTEND;TZID="India":20100629T120000
TRANSP:OPAQUE
DTSTAMP:20100713T071037Z
CLASS:PUBLIC
SUMMARY:meeting
UID:6011DDDD659E49D765257751001D2B4B-Lotus_Notes_Generated
X-LOTUS-UPDATE-SEQ:1
X-LOTUS-UPDATE-WISL:$S:1;$L:1;$B:1;$R:1;$E:1;$W:1;$O:1;$M:1
X-LOTUS-NOTESVERSION:2
X-LOTUS-APPTTYPE:0
X-LOTUS-CHILD_UID:6011DDDD659E49D765257751001D2B4B
END:VEVENT

Answer 1

The icalendar package looks nice.

For instance, to write a file:

from icalendar import Calendar, Event
from datetime import datetime
from pytz import UTC # timezone

cal = Calendar()
cal.add('prodid', '-//My calendar product//mxm.dk//')
cal.add('version', '2.0')

event = Event()
event.add('summary', 'Python meeting about calendaring')
event.add('dtstart', datetime(2005,4,4,8,0,0,tzinfo=UTC))
event.add('dtend', datetime(2005,4,4,10,0,0,tzinfo=UTC))
event.add('dtstamp', datetime(2005,4,4,0,10,0,tzinfo=UTC))
event['uid'] = '20050115T101010/[email protected]'
event.add('priority', 5)

cal.add_component(event)

f = open('example.ics', 'wb')
f.write(cal.to_ical())
f.close()

Tadaaa, you get this file:

BEGIN:VCALENDAR
PRODID:-//My calendar product//mxm.dk//
VERSION:2.0
BEGIN:VEVENT
DTEND;VALUE=DATE:20050404T100000Z
DTSTAMP;VALUE=DATE:20050404T001000Z
DTSTART;VALUE=DATE:20050404T080000Z
PRIORITY:5
SUMMARY:Python meeting about calendaring
UID:20050115T101010/[email protected]
END:VEVENT
END:VCALENDAR

But what lies in this file?

g = open('example.ics','rb')
gcal = Calendar.from_ical(g.read())
for component in gcal.walk():
    print component.name
g.close()

You can see it easily:

>>> 
VCALENDAR
VEVENT
>>> 

What about parsing the data about the events:

g = open('example.ics','rb')
gcal = Calendar.from_ical(g.read())
for component in gcal.walk():
    if component.name == "VEVENT":
        print(component.get('summary'))
        print(component.get('dtstart'))
        print(component.get('dtend'))
        print(component.get('dtstamp'))
g.close()

Now you get:

>>> 
Python meeting about calendaring
20050404T080000Z
20050404T100000Z
20050404T001000Z
>>>