conversion between iso8601 date format and unix epoch datetime (with timezone awareness)

gistfile1.py

from datetime import datetime, tzinfo, timedelta
import calendar
import re

def epoch_to_iso8601(timestamp, tz=None):
    """
    epoch_to_iso8601 - convert the unix epoch time into a iso8601 formatted date

    >>> epoch_to_iso8601(1341866722)
    '2012-07-09T22:45:22'
    >>> from pytz import timezone
    >>> tz = timezone("US/Eastern")
    >>> epoch_to_iso8601(1341866722, tz)
    '2012-07-09T22:45:22-05:00'
    """
    return datetime.fromtimestamp(timestamp, tz).isoformat()

def iso8601_to_epoch(datestring, tz=None):
    """
    iso8601_to_epoch - convert the iso8601 date into the unix epoch time

    >>> iso8601_to_epoch("2012-07-09T22:27:50.272517")
    1341872870
    >>> iso8601_to_epoch("2012-07-09T22:27:50.272517-05:00")
    1341854870
    >>> from pytz import timezone
    >>> tz = timezone("Australia/Sydney")
    >>> iso8601_to_epoch("2012-07-09T22:27:50.272517-05:00", tz)
    1341818870
    """
    (date, timezone) = parse_datestring(datestring)
    if timezone:
        date = timezone.localize(date)
    if tz:
        date.astimezone(tz)
    return calendar.timegm(date.timetuple())

class TimeZone(tzinfo):
    def __init__(self, offset):
        self.offset = offset

    def utcoffset(self, dt):
        return timedelta(minutes=self.offset)

    def tzname(self, dt):
        return str(self)

    def dst(self, dt):
        return timedelta(0)

    def __str__(self):
        return "%s%02d:%02d" % (["-","+"][self.offset>=0], self.offset/3600, self.offset%3600)


def parse_datestring(datestring):
    """
    parse_datestring - parse the iso8601 date string into datetime and timezone objects

    >>> parse_datestring("2012-07-09T22:27:50.272517")
    (datetime.datetime(2012, 7, 9, 22, 27, 50, 272517), None)
    >>> parse_datestring("2012-07-09T22:27:50.272517-05:00")
    (datetime.datetime(2012, 7, 9, 22, 27, 50, 272517), "-05:00")
    """
    timezone = None
    match = re.match('([0-9\-T:\.]+)(([+-])(\d{2}):(\d{2}))', datestring)
    if match:
        datestring = match.group(1)
        timezone = TimeZone({'-':-1,'+':1}[match.group(3)]*int(match.group(4))*3600+int(match.group(5)))

    return (datetime.strptime(datestring, "%Y-%m-%dT%H:%M:%S.%f"), timezone)

if __name__ == "__main__":
    import doctest
    doctest.testmod()

LICENSE

Copyright © Sébastien Quioc

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.

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