115 lines
3.8 KiB
Python
115 lines
3.8 KiB
Python
# tin.py - functions for handling Austrian tax identification numbers
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# coding: utf-8
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#
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# Copyright (C) 2017 Holvi Payment Services Oy
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# Copyright (C) 2018 Arthur de Jong
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301 USA
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r"""Abgabenkontonummer (Austrian tax identification number).
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The Austrian tax identification number (Abgabenkontonummer) consists of 2
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digits for the issuing tax office (Finanzamtsnummer) and 7 digits for the
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subject and a check digit (Steuernummer).
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More information:
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* https://de.wikipedia.org/wiki/Abgabenkontonummer
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* https://service.bmf.gv.at/Service/Anwend/Behoerden/show_mast.asp
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>>> validate('59-119/9013')
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'591199013'
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>>> validate('59-119/9013', office='St. Veit Wolfsberg')
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'591199013'
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>>> import json
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>>> print(json.dumps(info('59-119/9013'), indent=2, sort_keys=True))
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{
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"office": "St. Veit Wolfsberg",
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"region": "K\u00e4rnten"
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}
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>>> format('591199013')
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'59-119/9013'
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"""
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from __future__ import annotations
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from stdnum.exceptions import *
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from stdnum.util import clean, isdigits
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def compact(number: str) -> str:
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"""Convert the number to the minimal representation. This strips the
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number of any valid separators and removes surrounding whitespace."""
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return clean(number, ' -./,').strip()
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def _min_fa(office: str) -> str:
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"""Convert the tax office name to something that we can use for
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comparison without running into encoding issues."""
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return ''.join(
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x for x in office.lower()
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if x in 'bcdefghijklmnopqrstvwxyz')
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def calc_check_digit(number: str) -> str:
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"""Calculate the check digit."""
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number = compact(number)
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s = sum(
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int('0246813579'[int(n)]) if i % 2 else int(n)
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for i, n in enumerate(number[:8]))
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return str((10 - s) % 10)
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def info(number: str) -> dict[str, str]:
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"""Return a dictionary of data about the supplied number. This typically
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returns the the tax office and region."""
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number = compact(number)
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from stdnum import numdb
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return numdb.get('at/fa').info(number[:2])[0][1]
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def validate(number: str, office: str | None = None) -> str:
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"""Check if the number is a valid tax identification number. This checks
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the length and formatting. The tax office can be supplied to check that
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the number was issued in the specified tax office."""
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number = compact(number)
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if len(number) != 9:
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raise InvalidLength()
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if not isdigits(number):
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raise InvalidFormat()
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if calc_check_digit(number) != number[-1]:
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raise InvalidChecksum()
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i = info(number)
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if not i:
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raise InvalidComponent()
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if office and _min_fa(i.get('office', '')) != _min_fa(office):
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raise InvalidComponent()
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return number
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def is_valid(number: str, office: str | None = None) -> bool:
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"""Check if the number is a valid tax identification number. This checks
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the length, formatting and check digit."""
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try:
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return bool(validate(number, office))
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except ValidationError:
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return False
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def format(number: str) -> str:
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"""Reformat the number to the standard presentation format."""
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number = compact(number)
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return '%s-%s/%s' % (number[:2], number[2:5], number[5:])
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