diff options
Diffstat (limited to 'third_party/pyiso8601/iso8601/iso8601.py')
| -rw-r--r-- | third_party/pyiso8601/iso8601/iso8601.py | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/third_party/pyiso8601/iso8601/iso8601.py b/third_party/pyiso8601/iso8601/iso8601.py new file mode 100644 index 00000000000..1ae810ab9ae --- /dev/null +++ b/third_party/pyiso8601/iso8601/iso8601.py @@ -0,0 +1,214 @@ +"""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 +) +from decimal import Decimal +import logging +import sys +import re + +__all__ = ["parse_date", "ParseError", "UTC"] + +LOG = logging.getLogger(__name__) + +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 +) + +class ParseError(Exception): + """Raised when there is a problem parsing a date string""" + +# Yoinked from python docs +ZERO = timedelta(0) +class Utc(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() + +class FixedOffset(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 = 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) + ) + if isinstance(other, tzinfo): + return other == self + return False + + 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 + LOG.debug("Got %r for %r with default %r", value, key, 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) + +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() + LOG.debug("Parsed %s into %s with default timezone %s", datestring, groups, default_timezone) + + 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( + 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) |