# coding: utf-8
from __future__ import unicode_literals
import calendar
import regex as re
import sys
from datetime import datetime
from collections import OrderedDict
import six
from dateutil import parser
from dateutil.relativedelta import relativedelta
from .timezone_parser import pop_tz_offset_from_string
from .utils import strip_braces, apply_timezone
from .conf import apply_settings
binary_type = bytes if sys.version_info[0] == 3 else str
[docs]class new_parser(parser.parser):
"""
Implements an alternate parse method which supports preference to dates in future and past.
For more see issue #36
"""
[docs] def parse(self, timestr, default=None, ignoretz=False, settings=None, **kwargs):
# timestr needs to be a buffer as required by _parse
if isinstance(timestr, binary_type):
timestr = timestr.decode()
# Parse timestr
res = self._parse(timestr, **kwargs)
if res is None:
raise ValueError("unknown string format")
# Fill in missing date
new_date = self._populate(res, default, settings=settings)
# Clean hour and minutes, etc in case not defined
for e in ['hour', 'minute', 'second', 'microsecond']:
if not getattr(res, e):
new_date = new_date.replace(**{e: 0})
return new_date, self.get_period(res)
@staticmethod
[docs] def get_period(res):
periods = OrderedDict([
('day', ['day', 'weekday', 'hour', 'minute', 'second', 'microsecond']),
('month', ['month']),
('year', ['year']),
])
for period, markers in six.iteritems(periods):
for marker in markers:
if getattr(res, marker) is not None:
return period
@classmethod
def _populate(cls, res, default, settings=None):
new_date = default
# Populate all fields
repl = {}
for field in ['year', 'month', 'day', 'hour', 'minute', 'second', 'microsecond']:
value = getattr(res, field)
if value is not None:
repl[field] = value
# Fix day and populate date with result
repl_copy = repl.copy()
repl_copy['day'] = cls.get_valid_day(repl, new_date, settings=settings)
new_date = new_date.replace(**repl_copy)
# Fix weekday
if res.weekday is not None and not res.day:
new_date = new_date + relativedelta(weekday=res.weekday)
if new_date > datetime.utcnow():
new_date -= relativedelta(days=7)
# Correct date and return
return cls._correct(new_date, [key + 's' for key in repl.keys()], default, settings=settings)
@staticmethod
@apply_settings
[docs] def get_valid_day(res, new_date, settings=None):
_, tail = calendar.monthrange(res.get('year', new_date.year),
res.get('month', new_date.month))
if 'day' in res:
if res['day'] > tail:
raise ValueError('Day not in range for month',)
else:
return res['day']
options = {
'first': 1,
'last': tail,
'current': new_date.day if new_date.day <= tail else tail
}
return options[settings.PREFER_DAY_OF_MONTH]
@classmethod
def _correct(cls, date, given_fields, default, settings=None):
if settings.PREFER_DATES_FROM == 'current_period':
return date
for field in ['microseconds', 'seconds', 'minutes', 'hours', 'days',
'weeks', 'months', 'years']:
# Can't override a given field
if field in given_fields:
continue
# Try if applying the delta for this field corrects the problem
delta = relativedelta(**{field: 1})
# Run through corrections
corrected_date = cls._correct_for_future(date, delta, default, settings)
corrected_date = cls._correct_for_past(corrected_date, delta, default, settings)
# check if changed
if corrected_date != date:
date = corrected_date
break
return date
@staticmethod
def _correct_for_future(date, delta, default, settings=None):
if settings.PREFER_DATES_FROM != 'future':
return date
if date < default < date + delta:
date += delta
return date
@staticmethod
def _correct_for_past(date, delta, default, settings=None):
if settings.PREFER_DATES_FROM != 'past':
return date
if date > default > date - delta:
date -= delta
return date
[docs]def dateutil_parse(date_string, settings=None, **kwargs):
"""Wrapper function around dateutil.parser.parse
"""
today = datetime.utcnow()
kwargs.update(default=today)
date_string = re.sub(r'\b(year|month|week|day)\b', '', date_string, re.I)
# XXX: this is needed because of a bug in dateutil.parser
# that raises TypeError for an invalid string
# https://bugs.launchpad.net/dateutil/+bug/1042851
try:
return new_parser().parse(date_string, settings=settings, **kwargs)
except TypeError as e:
raise ValueError(e, "Invalid date: %s" % date_string)
[docs]class DateParser(object):
@apply_settings
[docs] def parse(self, date_string, settings=None):
date_string = six.text_type(date_string)
if not date_string.strip():
raise ValueError("Empty string")
date_string = strip_braces(date_string)
date_string, tz = pop_tz_offset_from_string(date_string)
date_obj, period = dateutil_parse(date_string, settings=settings)
if tz is not None:
date_obj = tz.localize(date_obj)
date_obj = apply_timezone(date_obj, settings.TIMEZONE)
if not settings.RETURN_AS_TIMEZONE_AWARE:
date_obj = date_obj.replace(tzinfo=None)
return date_obj, period
date_parser = DateParser()