[kronolith] timezone problem in Calendar Views

Systeembeheer BCS adje at bezoekerscentrumsonsbeek.nl
Sun Jun 22 20:15:19 UTC 2014 

Figured it out. Turns out there are 4 variables that influence the way  
kronolith stores, displays and edits calendar items:
1. default timezone of the user as set in global prefs> locale and time
2. timezone set while entering the event
3. timezone set in php/apache
4. nag on/off

Assuming the timezone settings have 2 possibilities (default or  
Europe/Amsterdam) this results in 16 possible scenarios. Tested them  
one by one resulting in the table below. In each case I entered an  
event starting at 10:00. The table lists the times as they are  
displayed in the calendar views, as the show up in the event editor  
and as they are stored in the sql dbase.

TZevent	TZ user	TZ php	NAG 	view	editor	db	db
						time	tz
default	default	not set	off	10	10	10	none
EA	default	not set	off	8	10	8	EA  > wrong time display in cal view
default	EA	not set	off	10	10	10	none
EA	EA	not set	off	8	10	8	EA  > wrong time display in cal view
default	default	EA	off	10	10	8	none
EA	default	EA	off	10	10	8	EA
default	EA	EA	off	10	10	8	none
EA	EA	EA	off	10	10	8	EA

default	default	not set	on	10	10	8	none
EA	default	not set	on	10	10	10	none
default	EA	not set	on	10	10	8	none
EA	EA	not set	on	10	10	8	EA
default	default	EA	on	10	10	8	none
EA	default	EA	on	10	10	8	EA
default	EA	EA	on	10	10	8	none
EA	EA	EA	on	10	10	8	EA

There are 2 scenario's in which kronolith places an event at another  
time in the calendar views then the entered time: rows 2 and 4.

The result of row 2 is somehow logical, with no timezone specified in  
neither user settings nor php Kronolith has no clue and assumes the  
user is at UTC (/etc/timezone seems not to be used by Krono). So when  
entering an event with tz E/A it subtracts 2 hours of the entered time  
to get UTC and stores this time.

The result of row 4 however does not make sense and is the first part  
of the problem I reported. Looking closely at the results you'll  
notice that with Nag disabled, the timezone setting of the user is  
ignored while with Nag enabled it is taken into account. This explains  
this behaviour.

The other problem is that Nag being enabled yes/no effects the way  
events are stored in the database (compare rows 9-12 with 13-16). This  
is a more sneaky problem as it will mess up things when Nag is  
disabled after the events were created and you will not notice until  
you do disable it. This is the second part of my problem and caused my  
database corruption with wrong event times.

The solution for now would be to always specify the timezone in  
php.ini, at least when installing a new system. However be careful on  
existing systems as changing it can mess up things in the existing  
calendar events.

I tested with setting timezones in php.ini before but somehow missed  
this all, too many variables and to much noise from events that were  
stored incorrectly.

Might be a good idea to fix this in Kronolith so the the users tz is  
always taken into account. Could prevent similar disasters for other  
users in the future

Thanks all for your contributions, I'll start thinking now on how to  
fix my database.


Citeren Systeembeheer BCS <adje at bezoekerscentrumsonsbeek.nl>:

> Citeren Jan Schneider <jan at horde.org>:
>
>> Zitat von Systeembeheer BCS <adje at bezoekerscentrumsonsbeek.nl>:
>>
>>> Citeren Arjen de Korte <arjen+horde at de-korte.org>:
>>>
>>>> Citeren Systeembeheer BCS <adje at bezoekerscentrumsonsbeek.nl>:
>>>>
>>>>> Ok, have been digging a bit deeper into this one. Changing timezones
>>>>> in
>>>>> php.ini made no difference. But I remember Kronolith working
>>>>> correctly when
>>>>> I first installed the system, so I decided to copy the complete
>>>>> present
>>>>> system config to a test machine and spend some late hours trying
>>>>> things
>>>>> out.
>>>>>
>>>>> Strange enough it turns out this problem is caused by disabling the
>>>>> Nag
>>>>> menu. I did so because we don't use Nag and we have to keep things
>>>>> in the
>>>>> UI as simple as possible over here. I disabled the Nag menu in
>>>>> horde/config/registry.local.php like this:
>>>>>
>>>>>>    /* disable nag
>>>>>>     'nag' => array(
>>>>>>         'name' => _("Tasks"),
>>>>>>         'provides' => 'tasks',
>>>>>>     ),
>>>>>>
>>>>>>     'nag-menu' => array(
>>>>>>         'status' => 'topbar',
>>>>>>         'app' => 'nag',
>>>>>>         'topbar_params' => array(
>>>>>>             'id' => 'menu'
>>>>>>         ),
>>>>>>         'menu_parent' => 'nag',
>>>>>>     ),
>>>>>> */
>>>>
>>>> The correct way to disable Nag (see the comments in the header of
>>>> 'horde/config/registry.php'), would be to put the following in
>>>> 'horde/config/registry.local.php':
>>>>
>>>> <?php
>>>> $this->applications['nag']['status'] = 'inactive';
>>>>
>>>>> This will remove the Nag menus allright but also seems to break
>>>>> something
>>>>> in Kronolith causing the timezone issue I described earlier.
>>>>
>>>> One lesson to learn, is that you should *never* redefine arrays in
>>>> your *.local.php files. Instead, just change the parameter that
>>>> you're interested in. This is documented in almost every
>>>> configuration file (at the top), just not in this one.
>>>
>>> yes, I already found that out. Should start reading the manual before
>>> and not afterwards. Lesson learned, thank you.
>>>
>>> However this is not the cause for my timezone issues. Disabling Nag
>>> the correct way results in the same behaviour. I verified it on the
>>> test machine:
>>>
>>> Corrected the bad registry.local.php, created a new registry.local.php
>>> containing the correct code for setting Nag inactive.
>>> Logged in, Nag inactive indeed.
>>> Entered 2 new items in my calendar, both from 10-11, one with timezone
>>> default and the other with timezone Europa/Amsterdam.
>>> The one with tz default is displayed correctly, the one with tz E/A
>>> appears from 8 to 9. This is happening with all items set to E/A,
>>> including existing items. Perfectly reproducible.
>>>
>>> So setting Nag inactive appears to be the cause rather than disabling
>>> Nag the wrong way. One way or another there must be some dependency
>>> that is broken this way?
>>>
>>>>> Re-enabling the Nag menu on my test machine caused all start- and
>>>>> ending
>>>>> times of all calender items that were set to "default" timezone to be
>>>>> modified (2 hours later). So I'd rather not do that on my production
>>>>> server...
>>>>
>>>> I'm afraid you'll have to bite the bullet here and fix this in the
>>>> database.
>>>
>>> I know... should not be a major problem though. All it takes is adding
>>> 2 hours to the times of any calendar items with the tz set to
>>> Europe/Amsterdam, sure I can work out something clever to do that
>>> automagically. But first I need to solve the initial problem.
>>>
>>>>> Would be very nice to have a better fix. Any suggestions welcome!
>>>>>
>>>>> thanks, Martin
>>>>>
>>>>> Citeren Systeembeheer BCS <adje at bezoekerscentrumsonsbeek.nl>:
>>>>>
>>>>>> We like the time of an event to appear in the different calendar
>>>>>> views
>>>>>> (Month, Week) so on the Calendar>User interface preference page we
>>>>>> set
>>>>>> "Choose the views to show event start and end times in:" to "Month,
>>>>>> Week
>>>>>> and Day Views". That works fine.
>>>>>>
>>>>>> Now when creating a new event in the calendar, some users change the
>>>>>> timezone in the event window from "Default" to "Europe/Amsterdam".
>>>>>> That
>>>>>> should not make a difference as Europe/Amsterdam is the default
>>>>>> timezone
>>>>>> anyway and all users are set to this. But it does make a difference:
>>>>>> - With the timezone of an event set to default, times displayed in
>>>>>> the
>>>>>> calendar views are correct.
>>>>>> - Events with the timezone set to Europe/Amsterdam appear with the
>>>>>> start- en ending times displayed with an offset of -2 hours.
>>>>>>
>>>>>> Running Horde Groupware 5.1.4, Kronolith version 4.1.5 on Ubuntu
>>>>>> server
>>>>>> 12.04LTS.
>>>>>> /etc/timezone on the system is set to Europe/Amsterdam, the 'date'
>>>>>> command shows the correct local time from the command line.
>>>>>>
>>>>>> Maybe related: although Ubuntu has the correct timezone setting, in
>>>>>> Horde's "global prefs">"Locale and Time" setting all users have to
>>>>>> set
>>>>>> the default timezone to Europe/Amsterdam anyway to get the correct
>>>>>> time
>>>>>> in Horde. I assume Horde always references to UTC regardless of
>>>>>> system
>>>>>> settings?
>>>>>>
>>>>>> Thanks...Martin
>>>>>
>>>>>  
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>>>>
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>>
>> Still cannot reproduce this with Nag disabled.
>
> So I started out with a complete fresh horde install. Removed everything
> according to instructions on http://wiki.horde.org/UninstallPEAR and
> reinstalled horde. Set only basic configuration for accessing the
> databases and left all other config files default.
>
> Logged in and entered 2 events in the calendar.
> Event 1: from 10:00-11:00, timezone default.
> Event 2: from 10:00-11:00, timezone Europe/Amsterdam
> I checked the database table kronolith_events and both items were stored
> in UTC times, so from 8:00-9:00. The timezone field for event 1 is empty
> (''), for event 2 it is set at "Europe/Amsterdam". Both events displayed
> correctly in the calendars.
>
> Next logged out, created a horde/config/registry.local.php containing
only
>
> <?php
>    $this->applications['nag']['status'] = 'inactive';
>
> Everything else left untouched. Logged back in, no Nag anymore.
> Both event 1 and 2 are now displayed from 8:00 to 9:00 in the calendar
> views.
> When opening event 1 in the event editor, tz is default as set before
> but times are now 8:00 to 9:00
> When opening event 2 in the event editor, nothing has changed so tz is
> E/A and times are 10:00 to 11:00
>
> Next I created 2 new events, same as before:
> Event 3: from 10:00-11:00, timezone default.
> Event 4: from 10:00-11:00, timezone Europe/Amsterdam
>
> Event 3 is shown correctly from 10-11 in the calendar views, but event 4
> shows up from 8-9.
> In the database, for event 3 times are set at 10:00 to 11:00 and tz at
> ''. So different from event 1.
> Event 4 times are set at 8:00 to 9:00 and tz = 'Europe/Amsterdam'. Same
> as event 2.
>
> Upon re-opening the events both show the correct times (10:00 - 11:00)
> in the event editor. While event 4 appears from 8-9 in the calendar
> views.
>
> Timezone default for the user under Global Preferences > locale and time
> was set at Europe/Amsterdam at all times. System timezone in
> /etc/timezone was also set at Europe/Amsterdam.
>
> So the event editor seems to behave differently from the calendar views
> with Nag disabled.
>
> With all other horde config files default, errors here can be probably
> ruled out now.
>
> But since Jan Schneider can not reproduce it, the only thing I can thing
> of is that some user settings in the database causes this. I re-used the
> existing mail- and horde databases. Could this be a clue pointing in the
> right direction?
>
>> --
>> Jan Schneider
>> The Horde Project
>> http://www.horde.org/
>> https://www.facebook.com/hordeproject
>>
>> --
>> kronolith mailing list
>> Frequently Asked Questions: http://wiki.horde.org/FAQ
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>
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