+"""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)