"""ISO 8601 date time string parsing
Basic usage:
>>> parse_date("2007-01-25T12:00:00Z")
datetime.datetime(2007, 1, 25, 12, 0, tzinfo=<iso8601.Utc ...>)
MIT License
Copyright (c) 2007 - 2015 Michael Twomey
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""
import time
import datetime
from decimal import Decimal
import sys
import re
import pytz
__all__ = ["parse_date", "ParseError", "UTC",
"FixedOffset", "TimeStamp"]
if sys.version_info >= (3, 0, 0):
_basestring = str
else:
_basestring = basestring
# Adapted from http://delete.me.uk/2005/03/iso8601.html
ISO8601_REGEX = re.compile(
r"""
(?P<year>[0-9]{4})
(
(
(-(?P<monthdash>[0-9]{1,2}))
|
(?P<month>[0-9]{2})
(?!$) # Don't allow YYYYMM
)
(
(
(-(?P<daydash>[0-9]{1,2}))
|
(?P<day>[0-9]{2})
)
(
(
(?P<separator>[ T])
(?P<hour>[0-9]{2})
(:{0,1}(?P<minute>[0-9]{2})){0,1}
(
:{0,1}(?P<second>[0-9]{1,2})
([.,](?P<second_fraction>[0-9]+)){0,1}
){0,1}
(?P<timezone>
Z
|
(
(?P<tz_sign>[-+])
(?P<tz_hour>[0-9]{2})
:{0,1}
(?P<tz_minute>[0-9]{2}){0,1}
)
){0,1}
){0,1}
)
){0,1} # YYYY-MM
){0,1} # YYYY only
$
""",
re.VERBOSE
)
[docs]class ParseError(Exception):
"""Raised when there is a problem parsing a date string"""
if sys.version_info >= (3, 2, 0):
UTC = datetime.timezone.utc
def FixedOffset(offset_hours, offset_minutes, name):
return datetime.timezone(
datetime.timedelta(
hours=offset_hours, minutes=offset_minutes),
name)
else:
# Yoinked from python docs
ZERO = datetime.timedelta(0)
class Utc(datetime.tzinfo):
"""UTC Timezone
"""
def utcoffset(self, dt):
return ZERO
def tzname(self, dt):
return "UTC"
def dst(self, dt):
return ZERO
def __repr__(self):
return "<iso8601.Utc>"
UTC = Utc()
[docs] class FixedOffset(datetime.tzinfo):
"""Fixed offset in hours and minutes from UTC
"""
def __init__(self, offset_hours, offset_minutes, name):
self.__offset_hours = offset_hours # Keep for later __getinitargs__
self.__offset_minutes = offset_minutes # Keep for later __getinitargs__
self.__offset = datetime.timedelta(
hours=offset_hours, minutes=offset_minutes)
self.__name = name
def __eq__(self, other):
if isinstance(other, FixedOffset):
return (
(other.__offset == self.__offset)
and
(other.__name == self.__name)
)
return NotImplemented
def __getinitargs__(self):
return (self.__offset_hours, self.__offset_minutes, self.__name)
def utcoffset(self, dt):
return self.__offset
def tzname(self, dt):
return self.__name
def dst(self, dt):
return ZERO
def __repr__(self):
return "<FixedOffset %r %r>" % (self.__name, self.__offset)
def to_int(d, key, default_to_zero=False, default=None, required=True):
"""Pull a value from the dict and convert to int
:param default_to_zero: If the value is None or empty, treat it as zero
:param default: If the value is missing in the dict use this default
"""
value = d.get(key) or default
if (value in ["", None]) and default_to_zero:
return 0
if value is None:
if required:
raise ParseError("Unable to read %s from %s" % (key, d))
else:
return int(value)
def parse_timezone(matches, default_timezone=UTC):
"""Parses ISO 8601 time zone specs into tzinfo offsets
"""
if matches["timezone"] == "Z":
return UTC
# This isn't strictly correct, but it's common to encounter dates without
# timezones so I'll assume the default (which defaults to UTC).
# Addresses issue 4.
if matches["timezone"] is None:
return default_timezone
sign = matches["tz_sign"]
hours = to_int(matches, "tz_hour")
minutes = to_int(matches, "tz_minute", default_to_zero=True)
description = "%s%02d:%02d" % (sign, hours, minutes)
if sign == "-":
hours = -hours
minutes = -minutes
return FixedOffset(hours, minutes, description)
[docs]def parse_date(datestring, default_timezone=UTC):
"""Parses ISO 8601 dates into datetime objects
The timezone is parsed from the date string. However it is quite common to
have dates without a timezone (not strictly correct). In this case the
default timezone specified in default_timezone is used. This is UTC by
default.
:param datestring: The date to parse as a string
:param default_timezone: A datetime tzinfo instance to use when no timezone
is specified in the datestring. If this is set to
None then a naive datetime object is returned.
:returns: A datetime.datetime instance
:raises: ParseError when there is a problem parsing the date or
constructing the datetime instance.
"""
if not isinstance(datestring, _basestring):
raise ParseError("Expecting a string %r" % datestring)
m = ISO8601_REGEX.match(datestring)
if not m:
raise ParseError("Unable to parse date string %r" % datestring)
groups = m.groupdict()
tz = parse_timezone(groups, default_timezone=default_timezone)
groups["second_fraction"] = int(Decimal("0.%s" % (groups["second_fraction"] or 0)) * Decimal("1000000.0"))
try:
return datetime.datetime(
year=to_int(groups, "year"),
month=to_int(groups, "month", default=to_int(groups, "monthdash", required=False, default=1)),
day=to_int(groups, "day", default=to_int(groups, "daydash", required=False, default=1)),
hour=to_int(groups, "hour", default_to_zero=True),
minute=to_int(groups, "minute", default_to_zero=True),
second=to_int(groups, "second", default_to_zero=True),
microsecond=groups["second_fraction"],
tzinfo=tz,
)
except Exception as e:
raise ParseError(e)
def local_tzname():
"""determine 'Etc/GMT%+d', e.g. 'Etc/GMT-2'"""
if time.daylight:
offsetHour = time.altzone / 3600
else:
offsetHour = time.timezone / 3600
return 'Etc/GMT%+d' % offsetHour
def get_utc_timestamp(dt):
"""datetime --> 2017-04-26T09:04:00.660000+00:00"""
if not isinstance(dt, datetime.datetime):
return
return dt.astimezone(tz=pytz.UTC)
def get_local_timestamp(dt):
"""datetime --> 2017-04-26T09:04:00.660000+02:00"""
tzname = local_tzname()
return dt.astimezone(tz=pytz.timezone(tzname))
[docs]class TimeStamp(object):
"""2017-04-26T09:04:00.660000+00:00"""
def __init__(self, datetimestr=None):
"""'2017-04-26T09:04:00.660000+00:00' --> datetime"""
if datetimestr is None:
self._datetime = datetime.datetime.now(tz=pytz.UTC)
else:
try:
self._datetime = parse_date(datetimestr)
except Exception as exp:
raise exp
def __repr__(self):
return self._datetime.isoformat()
def __str__(self):
return self._datetime.isoformat()
@property
def utc(self):
"""returns the utc.isoformat string
:returns str"""
return get_utc_timestamp(self._datetime).isoformat()
@property
def local(self):
"""returns the datetime isoformat string for the local timezone
:returns str"""
return get_local_timestamp(self._datetime).isoformat()
def today_str():
"""create timestamp for today (utc)
:return: '2020-12-11T00:00:00+00:00'
"""
today = datetime.datetime.today()
todaystr = datetime.date(today.year, today.month, today.day).isoformat()
return TimeStamp(todaystr).utc
def now_local_str():
"""create timestamp for now for local timezone
:return: '2020-12-11T00:00:00+00:00'
"""
todaystr = datetime.datetime.now().isoformat()
return TimeStamp(todaystr).local
def now_utc_str():
"""create timestamp for now for utc timezone
:return: '2020-12-11T00:00:00+00:00'
"""
todaystr = datetime.datetime.now().isoformat()
return TimeStamp(todaystr).utc