Recurrence / Google ICAL File

[Philipp Walther]

hi all

I'm trying to parse a simple iCal file exported from Google Calendar using this library.

It's 1 Event that has 35 recurrences - I'd expect getRecurrenceDates() to return those dates. Currently I get an empty list.

Do I misunderstand the API or is this work in progress, a malformed file maybe?

BEGIN:VCALENDAR
PRODID:-//Google Inc//Google Calendar 70.9054//EN
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:openHab
X-WR-TIMEZONE:Europe/Zurich
X-WR-CALDESC:openHab cal
BEGIN:VTIMEZONE
TZID:Europe/Zurich
X-LIC-LOCATION:Europe/Zurich
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:19700329T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:19701025T030000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Europe/Zurich:20141121T223000
DTEND;TZID=Europe/Zurich:20141121T233000
RRULE:FREQ=WEEKLY;COUNT=35;BYDAY=FR
DTSTAMP:20141121T210407Z
UID:ijfvd5k25ire72b57mcbpqo1b8@google.com
CREATED:20141121T202934Z
DESCRIPTION:start {\n update Window OPEN\n} \nend {\n update Window CLOSED\
 n}
LAST-MODIFIED:20141121T210359Z
LOCATION:Zurich\, Switzerland
SEQUENCE:2
STATUS:CONFIRMED
SUMMARY:open hab event
TRANSP:OPAQUE
END:VEVENT
END:VCALENDAR

My code:

    File f = new File("repeat_2times.txt");
    List<ICalendar> ical = Biweekly.parse(f).all();
    for (ICalendar iCalItem : ical) {
        List<VEvent> events = iCalItem.getEvents();
        for (VEvent evt : events) {
            List<RecurrenceDates> l = evt.getRecurrenceDates();
            LOG.info(l.size() + " list recurrence items");
        }
    }

~~~~~~~~

[Philipp Walther]

Oh I see now - It seems to need RDATE for that, it doesn't 'solve' RRULE for me. Although I can see there's some (Google) source in there for that..?

[Philipp Walther]

So I've tried to use the RecurrenceRule to google.RRule conversion, but I seem to lose the TimeZone information (on master). Bug in StreamReader? (0.3.3 doesn't have ByDay and other classes, so I cannot use that)

[Philipp Walther]

Ok, so if anyone is interested, I fixed it this way:

io.StreamReader:

   //remove the VTIMEZONE components from the iCalendar object
    if (toKeep.isEmpty() && vcalComponent != null) {
        ical.removeComponents(VTimezone.class);
    } else if(!toKeep.isEmpty()) {
        //keep the VTIMEZONE components that don't have IDs
        ical.getComponents().replace(VTimezone.class, toKeep);
    }

and then use the google code to convert:

                RecurrenceRule rule = evt.getRecurrenceRule();
                RRule grule = ICalTimeZone.convert(rule);
                VTimezone tz =     iCalItem.getComponent(VTimezone.class);

                TimeZone tzone =     TimeZone.getTimeZone(tz.getTimezoneId().getValue());

                DateValue dvstart =     ICalTimeZone.convert(evt.getDateStart());
                RecurrenceIterator iter =     RecurrenceIteratorFactory.createRecurrenceIterator(grule, dvstart, tzone);
                while(iter.hasNext()) {
                    System.out.println(iter.next());
                }

I made my own copy of IcalTimeZone and changed the convert(..) methods to public so I can access them.

I'm still not sure why 0.3.4 removes/hides the TimeZone information.

[Michael Angstadt]

Hi Philip,

The whole idea behind removing the VTIMEZONE components from the "ICalendar" object is that they are not part of the iCalendar "data-model" per se. They are only needed to let the parser know how to parse each date property value. After the values are parsed in their appropriate timezones, the VTIMEZONEs are not needed. However, you can still access them through the "ICalReader.getTimezoneInfo()" method if you wish.

This is part of the major timezone-related changes I've added to this version, so please let me know if you see anything wrong with this!

I just added a "getDateIterator()" method to the "RecurrenceRule" class, so you don't have to go through all that trouble.

:::java
RecurrenceRule rule = evt.getRecurrenceRule();
DateIterator it = rule.getDateIterator();
while(it.hasNext()){
  System.out.println(it.next());
}

I will be releasing a new stable version soon, so stay tuned! :D