| """ |
| Copyright (c) 2007 Michael Twomey |
| |
| 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. |
| |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 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 ...>) |
| >>> |
| """ |
| |
| # Taken from pyiso8601 which is licensed under the MIT license. |
| |
| import re |
| from datetime import tzinfo, datetime, timedelta |
| |
| __all__ = ["parse_date", "parse_date_allow_empty", "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]+))?)?" # NOQA |
| 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})") # NOQA |
| |
| |
| 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, allow_empty=False): |
| """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 datestring: |
| if allow_empty: |
| return None |
| |
| raise ValueError("datestring must be valid date string and not None") |
| |
| 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, |
| ) |
| |
| |
| def parse_date_allow_empty(datestring, default_timezone=UTC): |
| """ |
| Parses ISO 8601 dates into datetime objects, but allow empty values. |
| |
| In case empty value is found, None is returned. |
| """ |
| return parse_date(datestring=datestring, default_timezone=default_timezone, allow_empty=True) |