Convert PyGotham schedule into iCal format

sched_icalendar.py

"""
Parse the pygotham json schedule and make ical output
for use w/ google calendar, etc.

NOTE if you are going to serve the result, apparently google cal won't parse
it unless the header Content-Type: text/calendar is set!

Really useful for testing output: http://icalvalid.cloudapp.net
and http://severinghaus.org/projects/icv/
"""

import json
import urllib2
import icalendar
import datetime
import pytz

url = "https://pygotham.org/talkvote/full_schedule/"

def get_schedule(url=url):
    req = urllib2.Request(url=url, headers={'Accept': 'application/json'})
    raw = urllib2.urlopen(req, timeout=30).read()
    return json.loads(raw)


def parse_date(date):
    zone = pytz.timezone('US/Eastern')
    dt = datetime.datetime.strptime(date, '%Y-%m-%d %H:%M:%S')
    # Deal with timezones.
    # Note that if we pass tz-aware datetimes to Event.add(),
    # then the resulting output makes validators barf if it doesn't include
    # a timezone definition section, and I dunno how to add one.
    # So as a crappy workaround, we convert to UTC and then strip the zone info.
    dt = zone.localize(dt)
    dt = dt.astimezone(pytz.utc)
    dt = dt.replace(tzinfo=None)
    return dt

def make_ical_event(info):
    event = icalendar.Event()
    start = parse_date(info['talk_day_time'])

    try:
        room = 'Room %d' % int(info['room_number'])
    except:
        room = info['room_number']  # eg Plenary space

    speaker = info['full_name']

    event.add('summary', '%s (%s / %s)' % (info['title'], room, speaker)) # Subject.

    levels = '/'.join(info['levels']) or 'unknown'
    ttype = info['talktype']
    # TODO: no idea what the talk types mean. a, b, c ...?

    description = 'Speaker: %s. Levels: %s. Description: %s' % (speaker, levels, info['desc'])

    event.add('description', description)
    event.add('dtstart', start)
    event.add('dtend', parse_date(info['talk_end_time']))
    # Outlook demands this, per wikipedia; same as dtstart.
    event.add('dtstamp', start)
    event.add('location', room)

    # TODO: info['outline']?

    # Outlook demands this too, per wikipedia.
    # Value is arbitrary; we'll use the 'key'.
    event.add('uid', 'pygotham2/%s@pygotham.org' % info['key'])
    return event

def make_icalendar(url):
    sched = get_schedule()
    cal = icalendar.Calendar()
    cal.add('prodid', '-//PyGotham II ical script//pygotham.org//')
    cal.add('version', '2.0')

    for event_info in sched:
        event = make_ical_event(event_info)
        cal.add_component(event)
    return cal.to_ical()

if __name__ == '__main__':
    import sys
    output = make_icalendar(url=url)
    sys.stdout.write(output)