iCal calendar from Trac roadmap is incomprehensible to Google Calendar

[Jeffrey.Haemer]

Trac publishes a Roadmap calendar, of milestones, in iCal format. These calendars add to or import into gCal, but no events display. Here's why:

A VEVENT from Trac has date stamps in this format:

   DTSTAMP;VALUE=DATE:20061016

Google Calendar expects iCal date stamps to have this format:

   DTSTAMP;VALUE=DATE:20061016T222301Z

It appears that only the DTSTAMP field is the problem — all other date/time fields can have the first format.

Trac calendars do add or import successfully in Apple's iCal.

It would be useful to me, and the folks I work with, to be able to see Trac Roadmaps in Google Calendar. We may not be alone. :-)

[bbest@…]

I was able to simulate the desired time format by updating a single line of the write_date function ("write_prop…") in source:trunk/trac/ticket/roadmap.py​:

        def write_date(name, value, params={}):
            params['VALUE'] = 'DATE'
            #write_prop(name, strftime('%Y%m%d', value), params)
            write_prop(name, strftime('%Y%m%dT%H%M%SZ', value), params)

        # ... above gets called below by ...

            write_date('DTSTAMP', localtime(milestone['due']))
            write_date('DTSTART', localtime(milestone['due']))

But Google Calendar still cannot read my Trac Roadmap iCalendar file. It did seem to recognize the name of the calendar ("[projectname] - roadmap") after the fix though.

The above solution is not ideal, because the time specified should be Z as in Zulu = GMT. So the preferred time function to use would be gmtime instead of localtime. This function is not yet imported at the top of the file, but would look like so:

from time import localtime, strftime, time, gmtime

Please let me know (bbest@…) if anyone makes progress with this, as I would very much like to access these Roadmap iCalendars with Google Calendar. Trac + Google = good times ;)

Thanks!

[sid]

As the original poster pointed out, the problem is not with all dates listed in the calendar, just the VEVENT DTSTAMP ones. So the changes listed in comment:2 might be a little broad. The desired change is from:

BEGIN:VEVENT
UID:</trac/milestone/1.0.2@example.com/trac>
DTSTAMP;VALUE=DATE:20061110
DTSTART;VALUE=DATE:20061110

to:

BEGIN:VEVENT
UID:</trac/milestone/1.0.2@example.com/trac>
DTSTAMP:20061110T222301Z
DTSTART;VALUE=DATE:20061110

According to the ​iCal RFC 2445, the current implementation does not conform:

4.8.7.2 Date/Time Stamp

Property Name: DTSTAMP

Purpose: The property indicates the date/time that the instance of the iCalendar object was created.

Value Type: DATE-TIME

Description: The value MUST be specified in the UTC time format.

Example:

DTSTAMP:19971210T080000Z

[sid]

You probably want something more like this (untested):

trac/ticket/roadmap.py

@@ -293 +293 @@
             if milestone.has_key('due'):
                 write_prop('BEGIN', 'VEVENT')
                 write_prop('UID', uid)
-                write_date('DTSTAMP', localtime(milestone['due']))
+                write_utctime('DTSTAMP', localtime(milestone['due']))
                 write_date('DTSTART', localtime(milestone['due']))
                 write_prop('SUMMARY', 'Milestone %s' % milestone['name'])
                 write_prop('URL', req.base_url + '/milestone/' +

[sid]

I just tested the code in comment:4 and it worked for me on both Google Calendar and iCal.

[Christopher Lenz]

Patch applied in [4306], ported to stable in [4307]. Thanks for the patch and the testing!

[sid]

That patch was from me, but that's okay ;)

[Tim Hatch <trac@…>]

Just give my next one to Sid, we'll call it even.