mirror of
https://github.com/morpheus65535/bazarr
synced 2024-12-25 09:12:38 +00:00
a7fba2ee1b
As Brazil does not have Daylight Saving Time anymore as decided by it's government, pytz needed to be updated to have the new data about the country timezones. And as some in pytz calls in bazarr used tzlocal functions, that one needed also to be updated. Works fine now, tested on Brazil - Timezone America/Sao_Paulo This commit fixes #641
577 lines
19 KiB
Python
577 lines
19 KiB
Python
'''Base classes and helpers for building zone specific tzinfo classes'''
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from datetime import datetime, timedelta, tzinfo
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from bisect import bisect_right
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try:
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set
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except NameError:
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from sets import Set as set
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import pytz
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from pytz.exceptions import AmbiguousTimeError, NonExistentTimeError
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__all__ = []
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_timedelta_cache = {}
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def memorized_timedelta(seconds):
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'''Create only one instance of each distinct timedelta'''
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try:
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return _timedelta_cache[seconds]
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except KeyError:
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delta = timedelta(seconds=seconds)
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_timedelta_cache[seconds] = delta
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return delta
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_epoch = datetime.utcfromtimestamp(0)
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_datetime_cache = {0: _epoch}
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def memorized_datetime(seconds):
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'''Create only one instance of each distinct datetime'''
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try:
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return _datetime_cache[seconds]
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except KeyError:
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# NB. We can't just do datetime.utcfromtimestamp(seconds) as this
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# fails with negative values under Windows (Bug #90096)
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dt = _epoch + timedelta(seconds=seconds)
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_datetime_cache[seconds] = dt
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return dt
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_ttinfo_cache = {}
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def memorized_ttinfo(*args):
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'''Create only one instance of each distinct tuple'''
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try:
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return _ttinfo_cache[args]
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except KeyError:
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ttinfo = (
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memorized_timedelta(args[0]),
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memorized_timedelta(args[1]),
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args[2]
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)
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_ttinfo_cache[args] = ttinfo
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return ttinfo
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_notime = memorized_timedelta(0)
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def _to_seconds(td):
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'''Convert a timedelta to seconds'''
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return td.seconds + td.days * 24 * 60 * 60
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class BaseTzInfo(tzinfo):
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# Overridden in subclass
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_utcoffset = None
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_tzname = None
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zone = None
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def __str__(self):
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return self.zone
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class StaticTzInfo(BaseTzInfo):
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'''A timezone that has a constant offset from UTC
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These timezones are rare, as most locations have changed their
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offset at some point in their history
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'''
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def fromutc(self, dt):
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'''See datetime.tzinfo.fromutc'''
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if dt.tzinfo is not None and dt.tzinfo is not self:
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raise ValueError('fromutc: dt.tzinfo is not self')
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return (dt + self._utcoffset).replace(tzinfo=self)
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def utcoffset(self, dt, is_dst=None):
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'''See datetime.tzinfo.utcoffset
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is_dst is ignored for StaticTzInfo, and exists only to
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retain compatibility with DstTzInfo.
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'''
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return self._utcoffset
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def dst(self, dt, is_dst=None):
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'''See datetime.tzinfo.dst
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is_dst is ignored for StaticTzInfo, and exists only to
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retain compatibility with DstTzInfo.
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'''
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return _notime
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def tzname(self, dt, is_dst=None):
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'''See datetime.tzinfo.tzname
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is_dst is ignored for StaticTzInfo, and exists only to
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retain compatibility with DstTzInfo.
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'''
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return self._tzname
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def localize(self, dt, is_dst=False):
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'''Convert naive time to local time'''
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if dt.tzinfo is not None:
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raise ValueError('Not naive datetime (tzinfo is already set)')
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return dt.replace(tzinfo=self)
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def normalize(self, dt, is_dst=False):
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'''Correct the timezone information on the given datetime.
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This is normally a no-op, as StaticTzInfo timezones never have
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ambiguous cases to correct:
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>>> from pytz import timezone
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>>> gmt = timezone('GMT')
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>>> isinstance(gmt, StaticTzInfo)
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True
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>>> dt = datetime(2011, 5, 8, 1, 2, 3, tzinfo=gmt)
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>>> gmt.normalize(dt) is dt
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True
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The supported method of converting between timezones is to use
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datetime.astimezone(). Currently normalize() also works:
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>>> la = timezone('America/Los_Angeles')
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>>> dt = la.localize(datetime(2011, 5, 7, 1, 2, 3))
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>>> fmt = '%Y-%m-%d %H:%M:%S %Z (%z)'
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>>> gmt.normalize(dt).strftime(fmt)
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'2011-05-07 08:02:03 GMT (+0000)'
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'''
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if dt.tzinfo is self:
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return dt
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if dt.tzinfo is None:
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raise ValueError('Naive time - no tzinfo set')
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return dt.astimezone(self)
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def __repr__(self):
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return '<StaticTzInfo %r>' % (self.zone,)
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def __reduce__(self):
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# Special pickle to zone remains a singleton and to cope with
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# database changes.
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return pytz._p, (self.zone,)
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class DstTzInfo(BaseTzInfo):
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'''A timezone that has a variable offset from UTC
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The offset might change if daylight saving time comes into effect,
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or at a point in history when the region decides to change their
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timezone definition.
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'''
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# Overridden in subclass
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# Sorted list of DST transition times, UTC
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_utc_transition_times = None
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# [(utcoffset, dstoffset, tzname)] corresponding to
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# _utc_transition_times entries
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_transition_info = None
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zone = None
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# Set in __init__
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_tzinfos = None
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_dst = None # DST offset
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def __init__(self, _inf=None, _tzinfos=None):
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if _inf:
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self._tzinfos = _tzinfos
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self._utcoffset, self._dst, self._tzname = _inf
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else:
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_tzinfos = {}
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self._tzinfos = _tzinfos
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self._utcoffset, self._dst, self._tzname = (
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self._transition_info[0])
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_tzinfos[self._transition_info[0]] = self
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for inf in self._transition_info[1:]:
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if inf not in _tzinfos:
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_tzinfos[inf] = self.__class__(inf, _tzinfos)
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def fromutc(self, dt):
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'''See datetime.tzinfo.fromutc'''
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if (dt.tzinfo is not None and
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getattr(dt.tzinfo, '_tzinfos', None) is not self._tzinfos):
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raise ValueError('fromutc: dt.tzinfo is not self')
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dt = dt.replace(tzinfo=None)
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idx = max(0, bisect_right(self._utc_transition_times, dt) - 1)
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inf = self._transition_info[idx]
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return (dt + inf[0]).replace(tzinfo=self._tzinfos[inf])
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def normalize(self, dt):
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'''Correct the timezone information on the given datetime
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If date arithmetic crosses DST boundaries, the tzinfo
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is not magically adjusted. This method normalizes the
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tzinfo to the correct one.
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To test, first we need to do some setup
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>>> from pytz import timezone
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>>> utc = timezone('UTC')
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>>> eastern = timezone('US/Eastern')
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>>> fmt = '%Y-%m-%d %H:%M:%S %Z (%z)'
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We next create a datetime right on an end-of-DST transition point,
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the instant when the wallclocks are wound back one hour.
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>>> utc_dt = datetime(2002, 10, 27, 6, 0, 0, tzinfo=utc)
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>>> loc_dt = utc_dt.astimezone(eastern)
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>>> loc_dt.strftime(fmt)
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'2002-10-27 01:00:00 EST (-0500)'
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Now, if we subtract a few minutes from it, note that the timezone
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information has not changed.
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>>> before = loc_dt - timedelta(minutes=10)
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>>> before.strftime(fmt)
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'2002-10-27 00:50:00 EST (-0500)'
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But we can fix that by calling the normalize method
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>>> before = eastern.normalize(before)
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>>> before.strftime(fmt)
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'2002-10-27 01:50:00 EDT (-0400)'
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The supported method of converting between timezones is to use
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datetime.astimezone(). Currently, normalize() also works:
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>>> th = timezone('Asia/Bangkok')
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>>> am = timezone('Europe/Amsterdam')
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>>> dt = th.localize(datetime(2011, 5, 7, 1, 2, 3))
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>>> fmt = '%Y-%m-%d %H:%M:%S %Z (%z)'
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>>> am.normalize(dt).strftime(fmt)
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'2011-05-06 20:02:03 CEST (+0200)'
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'''
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if dt.tzinfo is None:
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raise ValueError('Naive time - no tzinfo set')
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# Convert dt in localtime to UTC
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offset = dt.tzinfo._utcoffset
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dt = dt.replace(tzinfo=None)
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dt = dt - offset
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# convert it back, and return it
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return self.fromutc(dt)
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def localize(self, dt, is_dst=False):
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'''Convert naive time to local time.
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This method should be used to construct localtimes, rather
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than passing a tzinfo argument to a datetime constructor.
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is_dst is used to determine the correct timezone in the ambigous
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period at the end of daylight saving time.
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>>> from pytz import timezone
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>>> fmt = '%Y-%m-%d %H:%M:%S %Z (%z)'
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>>> amdam = timezone('Europe/Amsterdam')
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>>> dt = datetime(2004, 10, 31, 2, 0, 0)
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>>> loc_dt1 = amdam.localize(dt, is_dst=True)
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>>> loc_dt2 = amdam.localize(dt, is_dst=False)
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>>> loc_dt1.strftime(fmt)
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'2004-10-31 02:00:00 CEST (+0200)'
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>>> loc_dt2.strftime(fmt)
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'2004-10-31 02:00:00 CET (+0100)'
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>>> str(loc_dt2 - loc_dt1)
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'1:00:00'
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Use is_dst=None to raise an AmbiguousTimeError for ambiguous
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times at the end of daylight saving time
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>>> try:
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... loc_dt1 = amdam.localize(dt, is_dst=None)
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... except AmbiguousTimeError:
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... print('Ambiguous')
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Ambiguous
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is_dst defaults to False
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>>> amdam.localize(dt) == amdam.localize(dt, False)
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True
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is_dst is also used to determine the correct timezone in the
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wallclock times jumped over at the start of daylight saving time.
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>>> pacific = timezone('US/Pacific')
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>>> dt = datetime(2008, 3, 9, 2, 0, 0)
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>>> ploc_dt1 = pacific.localize(dt, is_dst=True)
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>>> ploc_dt2 = pacific.localize(dt, is_dst=False)
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>>> ploc_dt1.strftime(fmt)
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'2008-03-09 02:00:00 PDT (-0700)'
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>>> ploc_dt2.strftime(fmt)
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'2008-03-09 02:00:00 PST (-0800)'
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>>> str(ploc_dt2 - ploc_dt1)
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'1:00:00'
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Use is_dst=None to raise a NonExistentTimeError for these skipped
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times.
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>>> try:
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... loc_dt1 = pacific.localize(dt, is_dst=None)
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... except NonExistentTimeError:
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... print('Non-existent')
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Non-existent
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'''
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if dt.tzinfo is not None:
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raise ValueError('Not naive datetime (tzinfo is already set)')
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# Find the two best possibilities.
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possible_loc_dt = set()
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for delta in [timedelta(days=-1), timedelta(days=1)]:
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loc_dt = dt + delta
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idx = max(0, bisect_right(
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self._utc_transition_times, loc_dt) - 1)
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inf = self._transition_info[idx]
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tzinfo = self._tzinfos[inf]
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loc_dt = tzinfo.normalize(dt.replace(tzinfo=tzinfo))
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if loc_dt.replace(tzinfo=None) == dt:
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possible_loc_dt.add(loc_dt)
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if len(possible_loc_dt) == 1:
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return possible_loc_dt.pop()
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# If there are no possibly correct timezones, we are attempting
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# to convert a time that never happened - the time period jumped
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# during the start-of-DST transition period.
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if len(possible_loc_dt) == 0:
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# If we refuse to guess, raise an exception.
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if is_dst is None:
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raise NonExistentTimeError(dt)
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# If we are forcing the pre-DST side of the DST transition, we
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# obtain the correct timezone by winding the clock forward a few
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# hours.
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elif is_dst:
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return self.localize(
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dt + timedelta(hours=6), is_dst=True) - timedelta(hours=6)
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# If we are forcing the post-DST side of the DST transition, we
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# obtain the correct timezone by winding the clock back.
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else:
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return self.localize(
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dt - timedelta(hours=6),
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is_dst=False) + timedelta(hours=6)
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# If we get this far, we have multiple possible timezones - this
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# is an ambiguous case occuring during the end-of-DST transition.
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# If told to be strict, raise an exception since we have an
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# ambiguous case
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if is_dst is None:
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raise AmbiguousTimeError(dt)
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# Filter out the possiblilities that don't match the requested
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# is_dst
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filtered_possible_loc_dt = [
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p for p in possible_loc_dt if bool(p.tzinfo._dst) == is_dst
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]
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# Hopefully we only have one possibility left. Return it.
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if len(filtered_possible_loc_dt) == 1:
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return filtered_possible_loc_dt[0]
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if len(filtered_possible_loc_dt) == 0:
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filtered_possible_loc_dt = list(possible_loc_dt)
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# If we get this far, we have in a wierd timezone transition
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# where the clocks have been wound back but is_dst is the same
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# in both (eg. Europe/Warsaw 1915 when they switched to CET).
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# At this point, we just have to guess unless we allow more
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# hints to be passed in (such as the UTC offset or abbreviation),
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# but that is just getting silly.
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#
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# Choose the earliest (by UTC) applicable timezone if is_dst=True
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# Choose the latest (by UTC) applicable timezone if is_dst=False
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# i.e., behave like end-of-DST transition
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dates = {} # utc -> local
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for local_dt in filtered_possible_loc_dt:
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utc_time = (
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local_dt.replace(tzinfo=None) - local_dt.tzinfo._utcoffset)
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assert utc_time not in dates
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dates[utc_time] = local_dt
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return dates[[min, max][not is_dst](dates)]
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def utcoffset(self, dt, is_dst=None):
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'''See datetime.tzinfo.utcoffset
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The is_dst parameter may be used to remove ambiguity during DST
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transitions.
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>>> from pytz import timezone
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>>> tz = timezone('America/St_Johns')
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>>> ambiguous = datetime(2009, 10, 31, 23, 30)
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>>> str(tz.utcoffset(ambiguous, is_dst=False))
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'-1 day, 20:30:00'
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>>> str(tz.utcoffset(ambiguous, is_dst=True))
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'-1 day, 21:30:00'
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>>> try:
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... tz.utcoffset(ambiguous)
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... except AmbiguousTimeError:
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... print('Ambiguous')
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Ambiguous
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'''
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if dt is None:
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return None
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elif dt.tzinfo is not self:
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dt = self.localize(dt, is_dst)
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return dt.tzinfo._utcoffset
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else:
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return self._utcoffset
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def dst(self, dt, is_dst=None):
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'''See datetime.tzinfo.dst
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The is_dst parameter may be used to remove ambiguity during DST
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transitions.
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>>> from pytz import timezone
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>>> tz = timezone('America/St_Johns')
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>>> normal = datetime(2009, 9, 1)
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>>> str(tz.dst(normal))
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'1:00:00'
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>>> str(tz.dst(normal, is_dst=False))
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'1:00:00'
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>>> str(tz.dst(normal, is_dst=True))
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'1:00:00'
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>>> ambiguous = datetime(2009, 10, 31, 23, 30)
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>>> str(tz.dst(ambiguous, is_dst=False))
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'0:00:00'
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>>> str(tz.dst(ambiguous, is_dst=True))
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'1:00:00'
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>>> try:
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... tz.dst(ambiguous)
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... except AmbiguousTimeError:
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... print('Ambiguous')
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Ambiguous
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'''
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if dt is None:
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return None
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elif dt.tzinfo is not self:
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dt = self.localize(dt, is_dst)
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return dt.tzinfo._dst
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else:
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return self._dst
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def tzname(self, dt, is_dst=None):
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'''See datetime.tzinfo.tzname
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The is_dst parameter may be used to remove ambiguity during DST
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transitions.
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>>> from pytz import timezone
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>>> tz = timezone('America/St_Johns')
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>>> normal = datetime(2009, 9, 1)
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>>> tz.tzname(normal)
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'NDT'
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>>> tz.tzname(normal, is_dst=False)
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'NDT'
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>>> tz.tzname(normal, is_dst=True)
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'NDT'
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>>> ambiguous = datetime(2009, 10, 31, 23, 30)
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>>> tz.tzname(ambiguous, is_dst=False)
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'NST'
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>>> tz.tzname(ambiguous, is_dst=True)
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'NDT'
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>>> try:
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... tz.tzname(ambiguous)
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... except AmbiguousTimeError:
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... print('Ambiguous')
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Ambiguous
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'''
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if dt is None:
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return self.zone
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elif dt.tzinfo is not self:
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dt = self.localize(dt, is_dst)
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return dt.tzinfo._tzname
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else:
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return self._tzname
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def __repr__(self):
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if self._dst:
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dst = 'DST'
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else:
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dst = 'STD'
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if self._utcoffset > _notime:
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return '<DstTzInfo %r %s+%s %s>' % (
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self.zone, self._tzname, self._utcoffset, dst
|
|
)
|
|
else:
|
|
return '<DstTzInfo %r %s%s %s>' % (
|
|
self.zone, self._tzname, self._utcoffset, dst
|
|
)
|
|
|
|
def __reduce__(self):
|
|
# Special pickle to zone remains a singleton and to cope with
|
|
# database changes.
|
|
return pytz._p, (
|
|
self.zone,
|
|
_to_seconds(self._utcoffset),
|
|
_to_seconds(self._dst),
|
|
self._tzname
|
|
)
|
|
|
|
|
|
def unpickler(zone, utcoffset=None, dstoffset=None, tzname=None):
|
|
"""Factory function for unpickling pytz tzinfo instances.
|
|
|
|
This is shared for both StaticTzInfo and DstTzInfo instances, because
|
|
database changes could cause a zones implementation to switch between
|
|
these two base classes and we can't break pickles on a pytz version
|
|
upgrade.
|
|
"""
|
|
# Raises a KeyError if zone no longer exists, which should never happen
|
|
# and would be a bug.
|
|
tz = pytz.timezone(zone)
|
|
|
|
# A StaticTzInfo - just return it
|
|
if utcoffset is None:
|
|
return tz
|
|
|
|
# This pickle was created from a DstTzInfo. We need to
|
|
# determine which of the list of tzinfo instances for this zone
|
|
# to use in order to restore the state of any datetime instances using
|
|
# it correctly.
|
|
utcoffset = memorized_timedelta(utcoffset)
|
|
dstoffset = memorized_timedelta(dstoffset)
|
|
try:
|
|
return tz._tzinfos[(utcoffset, dstoffset, tzname)]
|
|
except KeyError:
|
|
# The particular state requested in this timezone no longer exists.
|
|
# This indicates a corrupt pickle, or the timezone database has been
|
|
# corrected violently enough to make this particular
|
|
# (utcoffset,dstoffset) no longer exist in the zone, or the
|
|
# abbreviation has been changed.
|
|
pass
|
|
|
|
# See if we can find an entry differing only by tzname. Abbreviations
|
|
# get changed from the initial guess by the database maintainers to
|
|
# match reality when this information is discovered.
|
|
for localized_tz in tz._tzinfos.values():
|
|
if (localized_tz._utcoffset == utcoffset and
|
|
localized_tz._dst == dstoffset):
|
|
return localized_tz
|
|
|
|
# This (utcoffset, dstoffset) information has been removed from the
|
|
# zone. Add it back. This might occur when the database maintainers have
|
|
# corrected incorrect information. datetime instances using this
|
|
# incorrect information will continue to do so, exactly as they were
|
|
# before being pickled. This is purely an overly paranoid safety net - I
|
|
# doubt this will ever been needed in real life.
|
|
inf = (utcoffset, dstoffset, tzname)
|
|
tz._tzinfos[inf] = tz.__class__(inf, tz._tzinfos)
|
|
return tz._tzinfos[inf]
|