82 lines
2.6 KiB
Python
82 lines
2.6 KiB
Python
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# bn.py - functions for handling Canadian Business Numbers (BNs)
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#
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# Copyright (C) 2017 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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"""BN (Canadian Business Number).
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A Business Number (BN) is a 9-digit identification number for businesses
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issued by the Canada Revenue Agency for tax purposes. The 9-digit number can
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be followed by two letters (program identifier) and 4 digits (reference
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number) to form a program account (or BN15).
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More information:
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* https://www.canada.ca/en/services/taxes/business-number.html
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* https://www.ic.gc.ca/app/scr/cc/CorporationsCanada/fdrlCrpSrch.html?locale=en_CA/
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>>> validate('12302 6635')
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'123026635'
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>>> validate('12302 6635 RC 0001')
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'123026635RC0001'
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>>> validate('123456783')
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Traceback (most recent call last):
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...
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InvalidChecksum: ...
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>>> validate('12345678Z')
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Traceback (most recent call last):
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...
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InvalidFormat: ...
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"""
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from __future__ import annotations
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from stdnum import luhn
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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 validate(number: str) -> str:
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"""Check if the number is a valid BN or BN15. This checks the length,
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formatting and check digit."""
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number = compact(number)
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if len(number) not in (9, 15):
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raise InvalidLength()
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if not isdigits(number[:9]):
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raise InvalidFormat()
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luhn.validate(number[:9])
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if len(number) == 15:
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if number[9:11] not in ('RC', 'RM', 'RP', 'RT'):
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raise InvalidComponent()
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if not isdigits(number[11:]):
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raise InvalidFormat()
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return number
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def is_valid(number: str) -> bool:
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"""Check if the number is a valid BN or BN15."""
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try:
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return bool(validate(number))
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except ValidationError:
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return False
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