# -*- coding: utf-8 -*- # Copyright (c) 2019, Brandon Nielsen # All rights reserved. # # This software may be modified and distributed under the terms # of the BSD license. See the LICENSE file for details. from aniso8601.exceptions import ISOFormatError from aniso8601.builders.python import PythonTimeBuilder from aniso8601.resolution import DateResolution def get_date_resolution(isodatestr): #Valid string formats are: # #Y[YYY] #YYYY-MM-DD #YYYYMMDD #YYYY-MM #YYYY-Www #YYYYWww #YYYY-Www-D #YYYYWwwD #YYYY-DDD #YYYYDDD if isodatestr.startswith('+') or isodatestr.startswith('-'): raise NotImplementedError('ISO 8601 extended year representation ' 'not supported.') if isodatestr[0].isdigit() is False or isodatestr[-1].isdigit() is False: raise ISOFormatError('"{0}" is not a valid ISO 8601 date.' .format(isodatestr)) if isodatestr.find('W') != -1: #Handle ISO 8601 week date format hyphens_present = 1 if isodatestr.find('-') != -1 else 0 week_date_len = 7 + hyphens_present weekday_date_len = 8 + 2 * hyphens_present if len(isodatestr) == week_date_len: #YYYY-Www #YYYYWww return DateResolution.Week elif len(isodatestr) == weekday_date_len: #YYYY-Www-D #YYYYWwwD return DateResolution.Weekday else: raise ISOFormatError('"{0}" is not a valid ISO 8601 week date.' .format(isodatestr)) #If the size of the string of 4 or less, #assume its a truncated year representation if len(isodatestr) <= 4: return DateResolution.Year #An ISO string may be a calendar represntation if: # 1) When split on a hyphen, the sizes of the parts are 4, 2, 2 or 4, 2 # 2) There are no hyphens, and the length is 8 datestrsplit = isodatestr.split('-') #Check case 1 if len(datestrsplit) == 2: if len(datestrsplit[0]) == 4 and len(datestrsplit[1]) == 2: return DateResolution.Month if len(datestrsplit) == 3: if (len(datestrsplit[0]) == 4 and len(datestrsplit[1]) == 2 and len(datestrsplit[2]) == 2): return DateResolution.Day #Check case 2 if len(isodatestr) == 8 and isodatestr.find('-') == -1: return DateResolution.Day #An ISO string may be a ordinal date representation if: # 1) When split on a hyphen, the sizes of the parts are 4, 3 # 2) There are no hyphens, and the length is 7 #Check case 1 if len(datestrsplit) == 2: if len(datestrsplit[0]) == 4 and len(datestrsplit[1]) == 3: return DateResolution.Ordinal #Check case 2 if len(isodatestr) == 7 and isodatestr.find('-') == -1: return DateResolution.Ordinal #None of the date representations match raise ISOFormatError('"{0}" is not an ISO 8601 date, perhaps it ' 'represents a time or datetime.'.format(isodatestr)) def parse_date(isodatestr, builder=PythonTimeBuilder): #Given a string in any ISO 8601 date format, return a datetime.date #object that corresponds to the given date. Valid string formats are: # #Y[YYY] #YYYY-MM-DD #YYYYMMDD #YYYY-MM #YYYY-Www #YYYYWww #YYYY-Www-D #YYYYWwwD #YYYY-DDD #YYYYDDD # #Note that the ISO 8601 date format of ±YYYYY is expressly not supported return _RESOLUTION_MAP[get_date_resolution(isodatestr)](isodatestr, builder) def _parse_year(yearstr, builder): #yearstr is of the format Y[YYY] return builder.build_date(YYYY=yearstr) def _parse_calendar_day(datestr, builder): #datestr is of the format YYYY-MM-DD or YYYYMMDD if len(datestr) == 10: #YYYY-MM-DD yearstr = datestr[0:4] monthstr = datestr[5:7] daystr = datestr[8:] elif len(datestr) == 8: #YYYYMMDD yearstr = datestr[0:4] monthstr = datestr[4:6] daystr = datestr[6:] else: raise ISOFormatError('"{0}" is not a valid ISO 8601 calendar day.' .format(datestr)) return builder.build_date(YYYY=yearstr, MM=monthstr, DD=daystr) def _parse_calendar_month(datestr, builder): #datestr is of the format YYYY-MM if len(datestr) != 7: raise ISOFormatError('"{0}" is not a valid ISO 8601 calendar month.' .format(datestr)) yearstr = datestr[0:4] monthstr = datestr[5:] return builder.build_date(YYYY=yearstr, MM=monthstr) def _parse_week_day(datestr, builder): #datestr is of the format YYYY-Www-D, YYYYWwwD # #W is the week number prefix, ww is the week number, between 1 and 53 #0 is not a valid week number, which differs from the Python implementation # #D is the weekday number, between 1 and 7, which differs from the Python #implementation which is between 0 and 6 yearstr = datestr[0:4] #Week number will be the two characters after the W windex = datestr.find('W') weekstr = datestr[windex + 1:windex + 3] if datestr.find('-') != -1 and len(datestr) == 10: #YYYY-Www-D daystr = datestr[9:10] elif len(datestr) == 8: #YYYYWwwD daystr = datestr[7:8] else: raise ISOFormatError('"{0}" is not a valid ISO 8601 week date.' .format(datestr)) return builder.build_date(YYYY=yearstr, Www=weekstr, D=daystr) def _parse_week(datestr, builder): #datestr is of the format YYYY-Www, YYYYWww # #W is the week number prefix, ww is the week number, between 1 and 53 #0 is not a valid week number, which differs from the Python implementation yearstr = datestr[0:4] #Week number will be the two characters after the W windex = datestr.find('W') weekstr = datestr[windex + 1:windex + 3] return builder.build_date(YYYY=yearstr, Www=weekstr) def _parse_ordinal_date(datestr, builder): #datestr is of the format YYYY-DDD or YYYYDDD #DDD can be from 1 - 36[5,6], this matches Python's definition yearstr = datestr[0:4] if datestr.find('-') != -1: #YYYY-DDD daystr = datestr[(datestr.find('-') + 1):] else: #YYYYDDD daystr = datestr[4:] return builder.build_date(YYYY=yearstr, DDD=daystr) _RESOLUTION_MAP = { DateResolution.Day: _parse_calendar_day, DateResolution.Ordinal: _parse_ordinal_date, DateResolution.Month: _parse_calendar_month, DateResolution.Week: _parse_week, DateResolution.Weekday: _parse_week_day, DateResolution.Year: _parse_year }