diff options
author | Michael Twomey <michael.twomey@fieldaware.com> | 2013-08-29 15:01:13 +0100 |
---|---|---|
committer | Michael Twomey <michael.twomey@fieldaware.com> | 2013-08-29 15:01:13 +0100 |
commit | 488def46bf9fbc38f54b0ae6908364561116d430 (patch) | |
tree | 261a85a943989c3ed5705bec4c1d2c18d461796b /iso8601/iso8601.py | |
download | pyiso8601-488def46bf9fbc38f54b0ae6908364561116d430.tar.gz |
Importing r23 / 0.1.4 from https://code.google.com/p/pyiso8601/
Diffstat (limited to 'iso8601/iso8601.py')
-rw-r--r-- | iso8601/iso8601.py | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/iso8601/iso8601.py b/iso8601/iso8601.py new file mode 100644 index 0000000..f923938 --- /dev/null +++ b/iso8601/iso8601.py @@ -0,0 +1,102 @@ +"""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) |