Re: How to edit dexterity types without needing to know about their behaviors

On Fri, 2014-03-14 at 02:46 -0700, ajung wrote:
> ajung wrote
> > 
> > johannes raggam wrote
> >> 
> >> i'll fix that, probably at the wine and beer sprint. but then you'll
> >> still always get UTC datetime values instead of localized ones, if you
> >> get the start/end attributes directly from the context.
> >> 
> >>> Consistency-is-king
> >>> Andreas
> >> 
> >> pragmatism is okay.
> >> johannes
> 
> Here are the facts why plone.app.event currently freaks me out.
> 
> The source 'start' object is 
> v = DateTime('2008/09/09 09:00:00 GMT+2') 
> which translates to 07:00 UTC.
> 
> The migration code tries to concert the DateTime instance to a Python
> datetime instance with UTC timezone and setting the 'timezone' of the event
> object to 'Etc/GMT+2' using
> 
>                     v = v.asdatetime()
>                     tz = str(v.tzinfo)
>                     if tz.startswith('GMT'):
>                         tz = 'Etc/%s' % tz
>                     new_obj.timezone = tz
>                     acc = IEventAccessor(new_obj)
>                     v = v.replace(tzinfo=pytz.timezone('UTC')) 
>                     setattr(acc, k, v)

first, are you sure, that you want to use Etc/GMT+2 as timezone? Etc/GMT
is not GMT, see the answer here:
http://answers.yahoo.com/question/index?qid=20090707145844AANnghH

>>> import pytz
>>> from datetime import datetime
>>> vie = pytz.timezone('Europe/Vienna')
>>> etc = pytz.timezone('Etc/GMT+2')
>>> dt = vie.localize(datetime.now())
>>> dt
datetime.datetime(2014, 3, 14, 11, 13, 11, 629280, tzinfo=<DstTzInfo
'Europe/Vienna' CET+1:00:00 STD>)
>>> dt.astimezone(etc)
datetime.datetime(2014, 3, 14, 8, 13, 11, 629280, tzinfo=<StaticTzInfo
'Etc/GMT+2'>)

then, just set the timezone on the accessor and start and end datetime
as floating datetimes. if you don't have multiple timezone in the portal
you are migrating, that shouldn't be a problem.

the behavior's setter applies a FAKEZONE, just to be able to compare the
value against something already stored on the content object without.
that way, we avoid a "TypeError: can't compare offset-naive and
offset-aware datetimes", because the widget's value is timezone naive. 
as i said, i'm going to refactor this....

then, the data_postprocessing event handler (p.a.event.dx.behaviors,
line 427) takes the floating-timezone value with it's FAKEZONE, removes
it and converts that value to UTC, using the timezone attribute from the
content object.

i'm going to repeat myself, but i think that was not clear enough.



> 
> After the migration the event show up in Plone with 
> 
> 09.09.2008 um 07:00 bis 10.09.2008 um 15:00 (Etc/GMT+2 / UTC-200)
> ^^^^^^^^^^^^^^^^^^^^
> 
> Taking the debugger:
> 
> >>> ev = app.restrictedTraverse('eteaching/news/tagungen/ilias_2008/')
> >>> ev.start
> datetime.datetime(2008, 9, 9, 9, 0,
> tzinfo=<plone.app.event.dx.behaviors.FakeZone object at 0xa7c1250>)
> >>> ev = app.restrictedTraverse('eteaching/news/tagungen/ilias_2008/')
> >>> ev.timezone
> 'Etc/GMT+2'
> >>> ev.start
> datetime.datetime(2008, 9, 9, 9, 0,
> tzinfo=<plone.app.event.dx.behaviors.FakeZone object at 0xa7c1250>)
> >>> ev.start.tzinfo 
> <plone.app.event.dx.behaviors.FakeZone object at 0xa7c1250>
> >>> ev.start.tzinfo.tzname(ev.start)
> 'FAKEZONE'
> 
> That the hell is a FAKEZONE?
> 
> Obviously my code is wrong because it does not change the 'hour' from 9 to 7
> (because of the two hours offset).
> 
> So I changed the code to
> 
>     v = v.astimezone(pytz.utc)
> 
> In this case the output changed to 
> 
> 09.09.2008 um 05:00 ...
> ^^^^^^^^^^^^^^^^^^^^
> 
> ...which is even more weird.
> 
> -aj
> 
> 
> 
> 
> --
> View this message in context: http://plone.293351.n2.nabble.com/How-to-edit-dexterity-types-without-needing-to-know-about-their-behaviors-tp7570571p7570628.html
> Sent from the Core Developers mailing list archive at Nabble.com.
> 
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-- 
programmatic  web development
di(fh) johannes raggam / thet
python plone zope development
plone framework  team  member
mail: office-//[email protected]
web:  http://programmatic.pro
      http://bluedynamics.com

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