def get_timezone(zone=None):
"""Looks up a timezone by name and returns it. The timezone object
returned comes from ``pytz`` and corresponds to the `tzinfo` interface and
can be used with all of the functions of Babel that operate with dates.
If a timezone is not known a :exc:`LookupError` is raised. If `zone`
is ``None`` a local zone object is returned.
:param zone: the name of the timezone to look up. If a timezone object
itself is passed in, mit's returned unchanged.
"""
if zone is None:
return LOCALTZ
if not isinstance(zone, string_types):
return zone
try:
return _pytz.timezone(zone)
except _pytz.UnknownTimeZoneError:
raise LookupError('Unknown timezone %s' % zone)
python类tzinfo()的实例源码
def make_aware(value, timezone=None, is_dst=None):
"""
Makes a naive datetime.datetime in a given time zone aware.
"""
if timezone is None:
timezone = get_current_timezone()
if hasattr(timezone, 'localize'):
# This method is available for pytz time zones.
return timezone.localize(value, is_dst=is_dst)
else:
# Check that we won't overwrite the timezone of an aware datetime.
if is_aware(value):
raise ValueError(
"make_aware expects a naive datetime, got %s" % value)
# This may be wrong around DST changes!
return value.replace(tzinfo=timezone)
def is_ambiguous(self, dt):
"""
Whether or not the "wall time" of a given datetime is ambiguous in this
zone.
:param dt:
A :py:class:`datetime.datetime`, naive or time zone aware.
:return:
Returns ``True`` if ambiguous, ``False`` otherwise.
..versionadded:: 2.6.0
"""
dt = dt.replace(tzinfo=self)
wall_0 = enfold(dt, fold=0)
wall_1 = enfold(dt, fold=1)
same_offset = wall_0.utcoffset() == wall_1.utcoffset()
same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
return same_dt and not same_offset
def _fold_status(self, dt_utc, dt_wall):
"""
Determine the fold status of a "wall" datetime, given a representation
of the same datetime as a (naive) UTC datetime. This is calculated based
on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
datetimes, and that this offset is the actual number of hours separating
``dt_utc`` and ``dt_wall``.
:param dt_utc:
Representation of the datetime as UTC
:param dt_wall:
Representation of the datetime as "wall time". This parameter must
either have a `fold` attribute or have a fold-naive
:class:`datetime.tzinfo` attached, otherwise the calculation may
fail.
"""
if self.is_ambiguous(dt_wall):
delta_wall = dt_wall - dt_utc
_fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
else:
_fold = 0
return _fold
def _isdst(self, dt):
if not self.hasdst:
return False
elif dt is None:
return None
transitions = self.transitions(dt.year)
if transitions is None:
return False
dt = dt.replace(tzinfo=None)
isdst = self._naive_isdst(dt, transitions)
# Handle ambiguous dates
if not isdst and self.is_ambiguous(dt):
return not self._fold(dt)
else:
return isdst
def is_ambiguous(self, dt):
"""
Whether or not the "wall time" of a given datetime is ambiguous in this
zone.
:param dt:
A :py:class:`datetime.datetime`, naive or time zone aware.
:return:
Returns ``True`` if ambiguous, ``False`` otherwise.
..versionadded:: 2.6.0
"""
dt = dt.replace(tzinfo=self)
wall_0 = enfold(dt, fold=0)
wall_1 = enfold(dt, fold=1)
same_offset = wall_0.utcoffset() == wall_1.utcoffset()
same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
return same_dt and not same_offset
def _fold_status(self, dt_utc, dt_wall):
"""
Determine the fold status of a "wall" datetime, given a representation
of the same datetime as a (naive) UTC datetime. This is calculated based
on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
datetimes, and that this offset is the actual number of hours separating
``dt_utc`` and ``dt_wall``.
:param dt_utc:
Representation of the datetime as UTC
:param dt_wall:
Representation of the datetime as "wall time". This parameter must
either have a `fold` attribute or have a fold-naive
:class:`datetime.tzinfo` attached, otherwise the calculation may
fail.
"""
if self.is_ambiguous(dt_wall):
delta_wall = dt_wall - dt_utc
_fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
else:
_fold = 0
return _fold
def _isdst(self, dt):
if not self.hasdst:
return False
elif dt is None:
return None
transitions = self.transitions(dt.year)
if transitions is None:
return False
dt = dt.replace(tzinfo=None)
isdst = self._naive_isdst(dt, transitions)
# Handle ambiguous dates
if not isdst and self.is_ambiguous(dt):
return not self._fold(dt)
else:
return isdst
def is_ambiguous(self, dt):
"""
Whether or not the "wall time" of a given datetime is ambiguous in this
zone.
:param dt:
A :py:class:`datetime.datetime`, naive or time zone aware.
:return:
Returns ``True`` if ambiguous, ``False`` otherwise.
.. versionadded:: 2.6.0
"""
dt = dt.replace(tzinfo=self)
wall_0 = enfold(dt, fold=0)
wall_1 = enfold(dt, fold=1)
same_offset = wall_0.utcoffset() == wall_1.utcoffset()
same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
return same_dt and not same_offset
def _fold_status(self, dt_utc, dt_wall):
"""
Determine the fold status of a "wall" datetime, given a representation
of the same datetime as a (naive) UTC datetime. This is calculated based
on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
datetimes, and that this offset is the actual number of hours separating
``dt_utc`` and ``dt_wall``.
:param dt_utc:
Representation of the datetime as UTC
:param dt_wall:
Representation of the datetime as "wall time". This parameter must
either have a `fold` attribute or have a fold-naive
:class:`datetime.tzinfo` attached, otherwise the calculation may
fail.
"""
if self.is_ambiguous(dt_wall):
delta_wall = dt_wall - dt_utc
_fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
else:
_fold = 0
return _fold
def _isdst(self, dt):
if not self.hasdst:
return False
elif dt is None:
return None
transitions = self.transitions(dt.year)
if transitions is None:
return False
dt = dt.replace(tzinfo=None)
isdst = self._naive_isdst(dt, transitions)
# Handle ambiguous dates
if not isdst and self.is_ambiguous(dt):
return not self._fold(dt)
else:
return isdst
def is_ambiguous(self, dt):
"""
Whether or not the "wall time" of a given datetime is ambiguous in this
zone.
:param dt:
A :py:class:`datetime.datetime`, naive or time zone aware.
:return:
Returns ``True`` if ambiguous, ``False`` otherwise.
.. versionadded:: 2.6.0
"""
dt = dt.replace(tzinfo=self)
wall_0 = enfold(dt, fold=0)
wall_1 = enfold(dt, fold=1)
same_offset = wall_0.utcoffset() == wall_1.utcoffset()
same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
return same_dt and not same_offset
def _fold_status(self, dt_utc, dt_wall):
"""
Determine the fold status of a "wall" datetime, given a representation
of the same datetime as a (naive) UTC datetime. This is calculated based
on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
datetimes, and that this offset is the actual number of hours separating
``dt_utc`` and ``dt_wall``.
:param dt_utc:
Representation of the datetime as UTC
:param dt_wall:
Representation of the datetime as "wall time". This parameter must
either have a `fold` attribute or have a fold-naive
:class:`datetime.tzinfo` attached, otherwise the calculation may
fail.
"""
if self.is_ambiguous(dt_wall):
delta_wall = dt_wall - dt_utc
_fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
else:
_fold = 0
return _fold
def _isdst(self, dt):
if not self.hasdst:
return False
elif dt is None:
return None
transitions = self.transitions(dt.year)
if transitions is None:
return False
dt = dt.replace(tzinfo=None)
isdst = self._naive_isdst(dt, transitions)
# Handle ambiguous dates
if not isdst and self.is_ambiguous(dt):
return not self._fold(dt)
else:
return isdst
def is_ambiguous(self, dt):
"""
Whether or not the "wall time" of a given datetime is ambiguous in this
zone.
:param dt:
A :py:class:`datetime.datetime`, naive or time zone aware.
:return:
Returns ``True`` if ambiguous, ``False`` otherwise.
.. versionadded:: 2.6.0
"""
dt = dt.replace(tzinfo=self)
wall_0 = enfold(dt, fold=0)
wall_1 = enfold(dt, fold=1)
same_offset = wall_0.utcoffset() == wall_1.utcoffset()
same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
return same_dt and not same_offset
def _fold_status(self, dt_utc, dt_wall):
"""
Determine the fold status of a "wall" datetime, given a representation
of the same datetime as a (naive) UTC datetime. This is calculated based
on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
datetimes, and that this offset is the actual number of hours separating
``dt_utc`` and ``dt_wall``.
:param dt_utc:
Representation of the datetime as UTC
:param dt_wall:
Representation of the datetime as "wall time". This parameter must
either have a `fold` attribute or have a fold-naive
:class:`datetime.tzinfo` attached, otherwise the calculation may
fail.
"""
if self.is_ambiguous(dt_wall):
delta_wall = dt_wall - dt_utc
_fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
else:
_fold = 0
return _fold
def _isdst(self, dt):
if not self.hasdst:
return False
elif dt is None:
return None
transitions = self.transitions(dt.year)
if transitions is None:
return False
dt = dt.replace(tzinfo=None)
isdst = self._naive_isdst(dt, transitions)
# Handle ambiguous dates
if not isdst and self.is_ambiguous(dt):
return not self._fold(dt)
else:
return isdst
def get_timezone(zone=None):
"""Looks up a timezone by name and returns it. The timezone object
returned comes from ``pytz`` and corresponds to the `tzinfo` interface and
can be used with all of the functions of Babel that operate with dates.
If a timezone is not known a :exc:`LookupError` is raised. If `zone`
is ``None`` a local zone object is returned.
:param zone: the name of the timezone to look up. If a timezone object
itself is passed in, mit's returned unchanged.
"""
if zone is None:
return LOCALTZ
if not isinstance(zone, string_types):
return zone
try:
return _pytz.timezone(zone)
except _pytz.UnknownTimeZoneError:
raise LookupError('Unknown timezone %s' % zone)
def info(self, t=None):
if t is None:
dt = datetime.utcnow().replace(tzinfo=pytz.utc)
else:
# can't use utcfromtimestamp past 2038
dt = EPOCH + timedelta(0, t)
# need to normalize tzinfo for the datetime to deal with
# daylight savings time.
normalized_dt = self.tzinfo.normalize(dt.astimezone(self.tzinfo))
normalized_tzinfo = normalized_dt.tzinfo
offset = normalized_tzinfo.utcoffset(normalized_dt)
secs = offset.days * 24 * 60 * 60 + offset.seconds
dst = normalized_tzinfo.dst(normalized_dt)
if dst == timedelta(0):
is_dst = 0
else:
is_dst = 1
return secs, is_dst, normalized_tzinfo.tzname(normalized_dt)
def make_aware(value, timezone=None, is_dst=None):
"""
Makes a naive datetime.datetime in a given time zone aware.
"""
if timezone is None:
timezone = get_current_timezone()
if hasattr(timezone, 'localize'):
# This method is available for pytz time zones.
return timezone.localize(value, is_dst=is_dst)
else:
# Check that we won't overwrite the timezone of an aware datetime.
if is_aware(value):
raise ValueError(
"make_aware expects a naive datetime, got %s" % value)
# This may be wrong around DST changes!
return value.replace(tzinfo=timezone)
def make_aware(value, timezone=None, is_dst=None):
"""
Makes a naive datetime.datetime in a given time zone aware.
"""
if timezone is None:
timezone = get_current_timezone()
if hasattr(timezone, 'localize'):
# This method is available for pytz time zones.
return timezone.localize(value, is_dst=is_dst)
else:
# Check that we won't overwrite the timezone of an aware datetime.
if is_aware(value):
raise ValueError(
"make_aware expects a naive datetime, got %s" % value)
# This may be wrong around DST changes!
return value.replace(tzinfo=timezone)
def is_ambiguous(self, dt):
"""
Whether or not the "wall time" of a given datetime is ambiguous in this
zone.
:param dt:
A :py:class:`datetime.datetime`, naive or time zone aware.
:return:
Returns ``True`` if ambiguous, ``False`` otherwise.
..versionadded:: 2.6.0
"""
dt = dt.replace(tzinfo=self)
wall_0 = enfold(dt, fold=0)
wall_1 = enfold(dt, fold=1)
same_offset = wall_0.utcoffset() == wall_1.utcoffset()
same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
return same_dt and not same_offset
def _fold_status(self, dt_utc, dt_wall):
"""
Determine the fold status of a "wall" datetime, given a representation
of the same datetime as a (naive) UTC datetime. This is calculated based
on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
datetimes, and that this offset is the actual number of hours separating
``dt_utc`` and ``dt_wall``.
:param dt_utc:
Representation of the datetime as UTC
:param dt_wall:
Representation of the datetime as "wall time". This parameter must
either have a `fold` attribute or have a fold-naive
:class:`datetime.tzinfo` attached, otherwise the calculation may
fail.
"""
if self.is_ambiguous(dt_wall):
delta_wall = dt_wall - dt_utc
_fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
else:
_fold = 0
return _fold
def _isdst(self, dt):
if not self.hasdst:
return False
elif dt is None:
return None
transitions = self.transitions(dt.year)
if transitions is None:
return False
dt = dt.replace(tzinfo=None)
isdst = self._naive_isdst(dt, transitions)
# Handle ambiguous dates
if not isdst and self.is_ambiguous(dt):
return not self._fold(dt)
else:
return isdst
def __init__(self, weeks=0, days=0, hours=0, minutes=0, seconds=0, start_date=None,
end_date=None, timezone=None):
self.interval = timedelta(weeks=weeks, days=days, hours=hours, minutes=minutes,
seconds=seconds)
self.interval_length = timedelta_seconds(self.interval)
if self.interval_length == 0:
self.interval = timedelta(seconds=1)
self.interval_length = 1
if timezone:
self.timezone = astimezone(timezone)
elif start_date and start_date.tzinfo:
self.timezone = start_date.tzinfo
elif end_date and end_date.tzinfo:
self.timezone = end_date.tzinfo
else:
self.timezone = get_localzone()
start_date = start_date or (datetime.now(self.timezone) + self.interval)
self.start_date = convert_to_datetime(start_date, self.timezone, 'start_date')
self.end_date = convert_to_datetime(end_date, self.timezone, 'end_date')
def astimezone(obj):
"""
Interprets an object as a timezone.
:rtype: tzinfo
"""
if isinstance(obj, six.string_types):
return timezone(obj)
if isinstance(obj, tzinfo):
if not hasattr(obj, 'localize') or not hasattr(obj, 'normalize'):
raise TypeError('Only timezones from the pytz library are supported')
if obj.zone == 'local':
raise ValueError(
'Unable to determine the name of the local timezone -- you must explicitly '
'specify the name of the local timezone. Please refrain from using timezones like '
'EST to prevent problems with daylight saving time. Instead, use a locale based '
'timezone name (such as Europe/Helsinki).')
return obj
if obj is not None:
raise TypeError('Expected tzinfo, got %s instead' % obj.__class__.__name__)
def __init__(self, weeks=0, days=0, hours=0, minutes=0, seconds=0, start_date=None,
end_date=None, timezone=None):
self.interval = timedelta(weeks=weeks, days=days, hours=hours, minutes=minutes,
seconds=seconds)
self.interval_length = timedelta_seconds(self.interval)
if self.interval_length == 0:
self.interval = timedelta(seconds=1)
self.interval_length = 1
if timezone:
self.timezone = astimezone(timezone)
elif start_date and start_date.tzinfo:
self.timezone = start_date.tzinfo
elif end_date and end_date.tzinfo:
self.timezone = end_date.tzinfo
else:
self.timezone = get_localzone()
start_date = start_date or (datetime.now(self.timezone) + self.interval)
self.start_date = convert_to_datetime(start_date, self.timezone, 'start_date')
self.end_date = convert_to_datetime(end_date, self.timezone, 'end_date')
def astimezone(obj):
"""
Interprets an object as a timezone.
:rtype: tzinfo
"""
if isinstance(obj, six.string_types):
return timezone(obj)
if isinstance(obj, tzinfo):
if not hasattr(obj, 'localize') or not hasattr(obj, 'normalize'):
raise TypeError('Only timezones from the pytz library are supported')
if obj.zone == 'local':
raise ValueError(
'Unable to determine the name of the local timezone -- you must explicitly '
'specify the name of the local timezone. Please refrain from using timezones like '
'EST to prevent problems with daylight saving time. Instead, use a locale based '
'timezone name (such as Europe/Helsinki).')
return obj
if obj is not None:
raise TypeError('Expected tzinfo, got %s instead' % obj.__class__.__name__)
def make_aware(value, timezone=None, is_dst=None):
"""
Makes a naive datetime.datetime in a given time zone aware.
"""
if timezone is None:
timezone = get_current_timezone()
if hasattr(timezone, 'localize'):
# This method is available for pytz time zones.
return timezone.localize(value, is_dst=is_dst)
else:
# Check that we won't overwrite the timezone of an aware datetime.
if is_aware(value):
raise ValueError(
"make_aware expects a naive datetime, got %s" % value)
# This may be wrong around DST changes!
return value.replace(tzinfo=timezone)
def make_aware(value, timezone=None, is_dst=None):
"""
Makes a naive datetime.datetime in a given time zone aware.
"""
if timezone is None:
timezone = get_current_timezone()
if hasattr(timezone, 'localize'):
# This method is available for pytz time zones.
return timezone.localize(value, is_dst=is_dst)
else:
# Check that we won't overwrite the timezone of an aware datetime.
if is_aware(value):
raise ValueError(
"make_aware expects a naive datetime, got %s" % value)
# This may be wrong around DST changes!
return value.replace(tzinfo=timezone)
