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"""ISO 8601 date time string parsing
Basic usage:
>>> import iso8601
>>> iso8601.parse_date("2007-01-25T12:00:00Z")
datetime.datetime(2007, 1, 25, 12, 0, tzinfo=<iso8601.iso8601.Utc ...>)
>>>
"""
from datetime import datetime, timedelta, tzinfo
import re
__all__ = ["parse_date", "ParseError"]
# Adapted from http://delete.me.uk/2005/03/iso8601.html
ISO8601_REGEX = re.compile(r"(?P<year>[0-9]{4})(-(?P<month>[0-9]{1,2})(-(?P<day>[0-9]{1,2})"
r"((?P<separator>.)(?P<hour>[0-9]{2}):(?P<minute>[0-9]{2})(:(?P<second>[0-9]{2})(\.(?P<fraction>[0-9]+))?)?"
r"(?P<timezone>Z|(([-+])([0-9]{2}):([0-9]{2})))?)?)?)?"
)
TIMEZONE_REGEX = re.compile("(?P<prefix>[+-])(?P<hours>[0-9]{2}).(?P<minutes>[0-9]{2})")
class ParseError(Exception):
"""Raised when there is a problem parsing a date string"""
# Yoinked from python docs
ZERO = timedelta(0)
class Utc(tzinfo):
"""UTC
"""
def utcoffset(self, dt):
return ZERO
def tzname(self, dt):
return "UTC"
def dst(self, dt):
return ZERO
UTC = Utc()
class FixedOffset(tzinfo):
"""Fixed offset in hours and minutes from UTC
"""
def __init__(self, offset_hours, offset_minutes, name):
self.__offset = timedelta(hours=offset_hours, minutes=offset_minutes)
self.__name = 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>" % self.__name
def parse_timezone(tzstring, default_timezone=UTC):
"""Parses ISO 8601 time zone specs into tzinfo offsets
"""
if tzstring == "Z":
return default_timezone
# 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 tzstring is None:
return default_timezone
m = TIMEZONE_REGEX.match(tzstring)
prefix, hours, minutes = m.groups()
hours, minutes = int(hours), int(minutes)
if prefix == "-":
hours = -hours
minutes = -minutes
return FixedOffset(hours, minutes, tzstring)
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.
"""
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["timezone"], default_timezone=default_timezone)
if groups["fraction"] is None:
groups["fraction"] = 0
else:
groups["fraction"] = int(float("0.%s" % groups["fraction"]) * 1e6)
return datetime(int(groups["year"]), int(groups["month"]), int(groups["day"]),
int(groups["hour"]), int(groups["minute"]), int(groups["second"]),
int(groups["fraction"]), tz)