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# Copyright (C) 2018 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of nbxmpp.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 3
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; If not, see <http://www.gnu.org/licenses/>.
import re
import time
import logging
from datetime import datetime
from datetime import timedelta
from datetime import timezone
from datetime import tzinfo
log = logging.getLogger('nbxmpp.m.date_and_time')
PATTERN_DATETIME = re.compile(
r'([0-9]{4}-[0-9]{2}-[0-9]{2})'
r'T'
r'([0-9]{2}:[0-9]{2}:[0-9]{2})'
r'(\.[0-9]{0,6})?'
r'(?:[0-9]+)?'
r'(?:(Z)|(?:([-+][0-9]{2}):([0-9]{2})))$'
)
PATTERN_DELAY = re.compile(
r'([0-9]{4}-[0-9]{2}-[0-9]{2})'
r'T'
r'([0-9]{2}:[0-9]{2}:[0-9]{2})'
r'(\.[0-9]{0,6})?'
r'(?:[0-9]+)?'
r'(?:(Z)|(?:([-+][0]{2}):([0]{2})))$'
)
ZERO = timedelta(0)
HOUR = timedelta(hours=1)
SECOND = timedelta(seconds=1)
STDOFFSET = timedelta(seconds=-time.timezone)
if time.daylight:
DSTOFFSET = timedelta(seconds=-time.altzone)
else:
DSTOFFSET = STDOFFSET
DSTDIFF = DSTOFFSET - STDOFFSET
class LocalTimezone(tzinfo):
'''
A class capturing the platform's idea of local time.
May result in wrong values on historical times in
timezones where UTC offset and/or the DST rules had
changed in the past.
'''
def fromutc(self, dt):
assert dt.tzinfo is self
stamp = (dt - datetime(1970, 1, 1, tzinfo=self)) // SECOND
args = time.localtime(stamp)[:6]
dst_diff = DSTDIFF // SECOND
# Detect fold
fold = (args == time.localtime(stamp - dst_diff))
return datetime(*args, microsecond=dt.microsecond,
tzinfo=self, fold=fold)
def utcoffset(self, dt):
if self._isdst(dt):
return DSTOFFSET
return STDOFFSET
def dst(self, dt):
if self._isdst(dt):
return DSTDIFF
return ZERO
def tzname(self, dt):
return 'local'
@staticmethod
def _isdst(dt):
tt = (dt.year, dt.month, dt.day,
dt.hour, dt.minute, dt.second,
dt.weekday(), 0, 0)
stamp = time.mktime(tt)
tt = time.localtime(stamp)
return tt.tm_isdst > 0
def create_tzinfo(hours=0, minutes=0, tz_string=None):
if tz_string is None:
return timezone(timedelta(hours=hours, minutes=minutes))
if tz_string.lower() == 'z':
return timezone.utc
try:
hours, minutes = map(int, tz_string.split(':'))
except Exception:
log.warning('Wrong tz string: %s', tz_string)
return None
if hours not in range(-24, 24):
log.warning('Wrong tz string: %s', tz_string)
return None
if minutes not in range(0, 59):
log.warning('Wrong tz string: %s', tz_string)
return None
if hours in (24, -24) and minutes != 0:
log.warning('Wrong tz string: %s', tz_string)
return None
return timezone(timedelta(hours=hours, minutes=minutes))
def parse_datetime(timestring, check_utc=False,
convert='utc', epoch=False):
'''
Parse a XEP-0082 DateTime Profile String
:param timestring: a XEP-0082 DateTime profile formated string
:param check_utc: if True, returns None if timestring is not
a timestring expressing UTC
:param convert: convert the given timestring to utc or local time
:param epoch: if True, returns the time in epoch
Examples:
'2017-11-05T01:41:20Z'
'2017-11-05T01:41:20.123Z'
'2017-11-05T01:41:20.123+05:00'
return a datetime or epoch
'''
if timestring is None:
return None
if convert not in (None, 'utc', 'local'):
raise TypeError('"%s" is not a valid value for convert')
if check_utc:
match = PATTERN_DELAY.match(timestring)
else:
match = PATTERN_DATETIME.match(timestring)
if match:
timestring = ''.join(match.groups(''))
strformat = '%Y-%m-%d%H:%M:%S%z'
if match.group(3):
# Fractional second addendum to Time
strformat = '%Y-%m-%d%H:%M:%S.%f%z'
if match.group(4):
# UTC string denoted by addition of the character 'Z'
timestring = timestring[:-1] + '+0000'
try:
date_time = datetime.strptime(timestring, strformat)
except ValueError:
pass
else:
if check_utc:
if convert != 'utc':
raise ValueError(
'check_utc can only be used with convert="utc"')
date_time.replace(tzinfo=timezone.utc)
if epoch:
return date_time.timestamp()
return date_time
if convert == 'utc':
date_time = date_time.astimezone(timezone.utc)
if epoch:
return date_time.timestamp()
return date_time
if epoch:
# epoch is always UTC, use convert='utc' or check_utc=True
raise ValueError(
'epoch not available while converting to local')
if convert == 'local':
date_time = date_time.astimezone(LocalTimezone())
return date_time
# convert=None
return date_time
return None
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