DATE-TIME property formatting

[jparise]

I'm not clear on why vDatetime properties (such as DTSTART) use the VALUE=DATE-TIME: syntax:

DTSTART;TZID=Europe/Vienna;VALUE=DATE-TIME:20101010T100000

RFC 5545 Section 3.3.5 describes a simpler (and more commonly used?) Date-Time format:

   DTSTART:19970714T133000                   ; Local time
   DTSTART:19970714T173000Z                  ; UTC time
   DTSTART;TZID=America/New_York:19970714T133000
                                             ; Local time and time
                                             ; zone reference

Mac OS X's Calendar.app doesn't appear to like the former but will accept the latter.

[regebro]

That's a bug in Calendar.app, in that case. VALUE=DATE-TIME just specifies what type the value has, and it can be DATE or DATE-TIME. DATE-TIME is default though, so it doesn't need to be specified, but that Calendar.app doesn't like it being specified is definitely a bug.

I guess logic could be added to skip VALUE= when it is DATE-TIME, though.

[jparise]

This was my mistake. There was a differently problem (caused by my code) that was producing bad DATE-TIME values.

But that aside, it does seem like a nice improvement to skip VALUE= when it's not necessary.

[Hagb]

I use this workaround

from icalendar import vDDDTypes
from datetime import datetime
def add_datetime(component, name: str, time: datetime):
    vdatetime: vDDDTypes = vDDDTypes(time)
    if 'VALUE' in vdatetime.params and 'TZID' in vdatetime.params:
        vdatetime.params.pop('VALUE')
    component.add(name, vdatetime)

...
from icalendar import Event
from datetime import timedelta, timezone
tz = datetime(2021,1,1,tzinfo=tz)
event = Event()
add_datetime(event, 'DTEND', datetime(2021,1,2,3,4,5,tzinfo=timezone(timedelta(hours=8), "Asia/Shanghai")))
print(event.to_ical().decode())

BEGIN:VEVENT
DTEND;TZID=Asia/Shanghai:20210102T030405
END:VEVENT