Module win32timezone

win32timezone: Module for handling datetime.tzinfo time zones using the windows registry for time zone information. The time zone names are dependent on the registry entries defined by the operating system.

Comments

This module may be tested using the doctest module.

This module is licenced for use in Mark Hammond's pywin32 library under the same terms as the pywin32 library.

To use this time zone module with the datetime module, simply pass the TimeZoneInfo object to the datetime constructor. For example,

>>> import win32timezone, datetime

>>> assert 'Mountain Standard Time' in win32timezone.TimeZoneInfo.get_sorted_time_zone_names()

>>> MST = win32timezone.TimeZoneInfo('Mountain Standard Time')

>>> now = datetime.datetime.now(MST)

The now object is now a time-zone aware object, and daylight savings- aware methods may be called on it.

>>> now.utcoffset() in (datetime.timedelta(-1, 61200), datetime.timedelta(-1, 64800))

True

(note that the result of utcoffset call will be different based on when now was generated, unless standard time is always used)

>>> now = datetime.datetime.now(TimeZoneInfo('Mountain Standard Time', True))

>>> now.utcoffset()

datetime.timedelta(-1, 61200)

>>> aug2 = datetime.datetime(2003, 8, 2, tzinfo = MST)

>>> tuple(aug2.utctimetuple())

(2003, 8, 2, 6, 0, 0, 5, 214, 0)

>>> nov2 = datetime.datetime(2003, 11, 25, tzinfo = MST)

>>> tuple(nov2.utctimetuple())

(2003, 11, 25, 7, 0, 0, 1, 329, 0)

To convert from one timezone to another, just use the astimezone method.

>>> aug2.isoformat()

'2003-08-02T00:00:00-06:00'

>>> aug2est = aug2.astimezone(win32timezone.TimeZoneInfo('Eastern Standard Time'))

>>> aug2est.isoformat()

'2003-08-02T02:00:00-04:00'

calling the displayName member will return the display name as set in the registry.

>>> est = win32timezone.TimeZoneInfo('Eastern Standard Time')

>>> str(est.displayName)

'(UTC-05:00) Eastern Time (US & Canada)'

>>> gmt = win32timezone.TimeZoneInfo('GMT Standard Time', True)

>>> str(gmt.displayName)

'(UTC) Dublin, Edinburgh, Lisbon, London'

To get the complete list of available time zone keys,

>>> zones = win32timezone.TimeZoneInfo.get_all_time_zones()

If you want to get them in an order that's sorted longitudinally

>>> zones = win32timezone.TimeZoneInfo.get_sorted_time_zones()

TimeZoneInfo now supports being pickled and comparison

>>> import pickle

>>> tz = win32timezone.TimeZoneInfo('China Standard Time')

>>> tz == pickle.loads(pickle.dumps(tz))

True

It's possible to construct a TimeZoneInfo from a TimeZoneDescription including the currently-defined zone.

>>> tz = win32timezone.TimeZoneInfo(TimeZoneDefinition.current())

>>> tz == pickle.loads(pickle.dumps(tz))

True

>>> aest = win32timezone.TimeZoneInfo('AUS Eastern Standard Time')

>>> est = win32timezone.TimeZoneInfo('E. Australia Standard Time')

>>> dt = datetime.datetime(2006, 11, 11, 1, 0, 0, tzinfo = aest)

>>> estdt = dt.astimezone(est)

>>> estdt.strftime('%Y-%m-%d %H:%M:%S')

'2006-11-11 00:00:00'


>>> dt = datetime.datetime(2007, 1, 12, 1, 0, 0, tzinfo = aest)

>>> estdt = dt.astimezone(est)

>>> estdt.strftime('%Y-%m-%d %H:%M:%S')

'2007-01-12 00:00:00'


>>> dt = datetime.datetime(2007, 6, 13, 1, 0, 0, tzinfo = aest)

>>> estdt = dt.astimezone(est)

>>> estdt.strftime('%Y-%m-%d %H:%M:%S')

'2007-06-13 01:00:00'

Microsoft now has a patch for handling time zones in 2007 (see http://support.microsoft.com/gp/cp_dst)

As a result, patched systems will give an incorrect result for dates prior to the designated year except for Vista and its successors, which have dynamic time zone support.

>>> nov2_pre_change = datetime.datetime(2003, 11, 2, tzinfo = MST)

>>> old_response = (2003, 11, 2, 7, 0, 0, 6, 306, 0)

>>> incorrect_patch_response = (2003, 11, 2, 6, 0, 0, 6, 306, 0)

>>> pre_response = nov2_pre_change.utctimetuple()

>>> pre_response in (old_response, incorrect_patch_response)

True

Furthermore, unpatched systems pre-Vista will give an incorrect result for dates after 2007.

>>> nov2_post_change = datetime.datetime(2007, 11, 2, tzinfo = MST)

>>> incorrect_unpatched_response = (2007, 11, 2, 7, 0, 0, 4, 306, 0)

>>> new_response = (2007, 11, 2, 6, 0, 0, 4, 306, 0)

>>> post_response = nov2_post_change.utctimetuple()

>>> post_response in (new_response, incorrect_unpatched_response)

True

There is a function you can call to get some capabilities of the time zone data.

>>> caps = GetTZCapabilities()

>>> isinstance(caps, dict)

True

>>> 'MissingTZPatch' in caps

True

>>> 'DynamicTZSupport' in caps

True

>>> both_dates_correct = (pre_response == old_response and post_response == new_response)

>>> old_dates_wrong = (pre_response == incorrect_patch_response)

>>> new_dates_wrong = (post_response == incorrect_unpatched_response)


>>> caps['DynamicTZSupport'] == both_dates_correct

True


>>> (not caps['DynamicTZSupport'] and caps['MissingTZPatch']) == new_dates_wrong

True


>>> (not caps['DynamicTZSupport'] and not caps['MissingTZPatch']) == old_dates_wrong

True

This test helps ensure language support for unicode characters

>>> x = TIME_ZONE_INFORMATION(0, u'franÃ§ais')

Test conversion from one time zone to another at a DST boundary

>>> tz_hi = TimeZoneInfo('Hawaiian Standard Time')

>>> tz_pac = TimeZoneInfo('Pacific Standard Time')

>>> time_before = datetime.datetime(2011, 11, 5, 15, 59, 59, tzinfo=tz_hi)

>>> tz_hi.utcoffset(time_before)

datetime.timedelta(-1, 50400)

>>> tz_hi.dst(time_before)

datetime.timedelta(0)

Hawaii doesn't need dynamic TZ info

>>> getattr(tz_hi, 'dynamicInfo', None)

Here's a time that gave some trouble as reported in #3523104 because one minute later, the equivalent UTC time changes from DST in the U.S.

>>> dt_hi = datetime.datetime(2011, 11, 5, 15, 59, 59, 0, tzinfo=tz_hi)

>>> dt_hi.timetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=5, tm_hour=15, tm_min=59, tm_sec=59, tm_wday=5, tm_yday=309, tm_isdst=0)

>>> dt_hi.utctimetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=6, tm_hour=1, tm_min=59, tm_sec=59, tm_wday=6, tm_yday=310, tm_isdst=0)

Convert the time to pacific time.

>>> dt_pac = dt_hi.astimezone(tz_pac)

>>> dt_pac.timetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=5, tm_hour=18, tm_min=59, tm_sec=59, tm_wday=5, tm_yday=309, tm_isdst=1)

Notice that the UTC time is almost 2am.

>>> dt_pac.utctimetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=6, tm_hour=1, tm_min=59, tm_sec=59, tm_wday=6, tm_yday=310, tm_isdst=0)

Now do the same tests one minute later in Hawaii.

>>> time_after = datetime.datetime(2011, 11, 5, 16, 0, 0, 0, tzinfo=tz_hi)

>>> tz_hi.utcoffset(time_after)

datetime.timedelta(-1, 50400)

>>> tz_hi.dst(time_before)

datetime.timedelta(0)

>>> dt_hi = datetime.datetime(2011, 11, 5, 16, 0, 0, 0, tzinfo=tz_hi)

>>> print dt_hi.timetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=5, tm_hour=16, tm_min=0, tm_sec=0, tm_wday=5, tm_yday=309, tm_isdst=0)

>>> print dt_hi.utctimetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=6, tm_hour=2, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=310, tm_isdst=0)

According to the docs, this is what astimezone does.

>>> utc = (dt_hi - dt_hi.utcoffset()).replace(tzinfo=tz_pac)

>>> utc

datetime.datetime(2011, 11, 6, 2, 0, tzinfo=TimeZoneInfo('Pacific Standard Time'))

>>> tz_pac.fromutc(utc) == dt_hi.astimezone(tz_pac)

True

>>> tz_pac.fromutc(utc)

datetime.datetime(2011, 11, 5, 19, 0, tzinfo=TimeZoneInfo('Pacific Standard Time'))

Make sure the converted time is correct.

>>> dt_pac = dt_hi.astimezone(tz_pac)

>>> dt_pac.timetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=5, tm_hour=19, tm_min=0, tm_sec=0, tm_wday=5, tm_yday=309, tm_isdst=1)

>>> dt_pac.utctimetuple()

time.struct_time(tm_year=2011, tm_mon=11, tm_mday=6, tm_hour=2, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=310, tm_isdst=0)

Check some internal methods

>>> tz_pac._getStandardBias(datetime.datetime(2011, 1, 1))

datetime.timedelta(0, 28800)

>>> tz_pac._getDaylightBias(datetime.datetime(2011, 1, 1))

datetime.timedelta(0, 25200)

Test the offsets

>>> offset = tz_pac.utcoffset(datetime.datetime(2011, 11, 6, 2, 0))

>>> offset == datetime.timedelta(hours=-8)

True

>>> dst_offset = tz_pac.dst(datetime.datetime(2011, 11, 6, 2, 0) + offset)

>>> dst_offset == datetime.timedelta(hours=1)

True

>>> (offset + dst_offset) == datetime.timedelta(hours=-7)

True

Test offsets that occur right at the DST changeover

>>> datetime.datetime.utcfromtimestamp(1320570000).replace(

...     tzinfo=TimeZoneInfo.utc()).astimezone(tz_pac)

datetime.datetime(2011, 11, 6, 1, 0, tzinfo=TimeZoneInfo('Pacific Standard Time'))

Methods

GetTZCapabilities: Run a few known tests to determine the capabilities of the time zone database
now: Return the local time now with timezone awareness as enabled
resolveMUITimeZone: Resolve a multilingual user interface resource for the time zone name
utcnow: Return the UTC time now with timezone awareness as enabled

Classes

TimeZoneInfo: Main class for handling Windows time zones.
TimeZoneDefinition: A time zone definition class based on the win32
RangeMap: A dictionary-like object that uses the keys as bounds for a range.