Kakao calendar birthdays to iCal/ics

kakao_to_ical.py

# events.json   https://calendar.kakao.com/web/events?from=20230625T000000Z&to=20240624T235959Z&birthday=true&referer=month
# friends.json  https://calendar.kakao.com/web/talk/friends 

cal_template = """BEGIN:VCALENDAR
PRODID:-//Talk Calendar//iCal4j 2.0//EN
VERSION:2.0
CALSCALE:GREGORIAN
X-WR-CALNAME:
{}
END:VCALENDAR
"""

birthday_template = """BEGIN:VEVENT
DTSTAMP:20230801T000000Z
DTSTART;VALUE=DATE:{dtstart}
DTEND;VALUE=DATE:{dtend}
RRULE:FREQ=YEARLY;WKST=MO;INTERVAL=1
SUMMARY:{friend_name} 생일
UID:{uid}@kakao.com
END:VEVENT
"""

id_to_name = {}
for friend in friends:
    id_to_name[friend['talkUserId']] = friend['name']
    

vevents = [
    birthday_template.format(dtstart=e['startAt'][:8], 
        dtend=e['endAt'][:8], 
        friend_name=id_to_name[e['talkUserId']], 
        uid=e['talkUserId']
    ) 
    for e in events if e.get('type', '')=='BIRTHDAY'
]

with open('birthdays.ics', 'w') as f:
    f.write(cal_template.format(''.join(vevents)))