91 lines
2.9 KiB
Python
91 lines
2.9 KiB
Python
|
# iso11649.py - functions for performing the ISO 11649 checksum validation
|
||
|
|
# for structured creditor reference numbers
|
||
|
|
#
|
||
|
|
# Copyright (C) 2018 Esben Toke Christensen
|
||
|
|
#
|
||
|
|
# This library is free software; you can redistribute it and/or
|
||
|
|
# modify it under the terms of the GNU Lesser General Public
|
||
|
|
# License as published by the Free Software Foundation; either
|
||
|
|
# version 2.1 of the License, or (at your option) any later version.
|
||
|
|
#
|
||
|
|
# This library is distributed in the hope that it will be useful,
|
||
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
|
# Lesser General Public License for more details.
|
||
|
|
#
|
||
|
|
# You should have received a copy of the GNU Lesser General Public
|
||
|
|
# License along with this library; if not, write to the Free Software
|
||
|
|
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
||
|
|
# 02110-1301 USA
|
||
|
|
|
||
|
|
"""ISO 11649 (Structured Creditor Reference).
|
||
|
|
|
||
|
|
The ISO 11649 structured creditor number consists of 'RF' followed by two
|
||
|
|
check digits and up to 21 digits. The number may contain letters.
|
||
|
|
|
||
|
|
The reference number is validated by moving RF and the check digits to the
|
||
|
|
end of the number, and checking that the ISO 7064 Mod 97, 10 checksum of this
|
||
|
|
string is 1.
|
||
|
|
|
||
|
|
More information:
|
||
|
|
|
||
|
|
* https://en.wikipedia.org/wiki/Creditor_Reference
|
||
|
|
|
||
|
|
>>> validate('RF18 5390 0754 7034')
|
||
|
|
'RF18539007547034'
|
||
|
|
>>> validate('RF18 5390 0754 70Y')
|
||
|
|
'RF185390075470Y'
|
||
|
|
>>> is_valid('RF18 5390 0754 7034')
|
||
|
|
True
|
||
|
|
>>> validate('RF17 5390 0754 7034')
|
||
|
|
Traceback (most recent call last):
|
||
|
|
...
|
||
|
|
InvalidChecksum: ...
|
||
|
|
>>> format('RF18539007547034')
|
||
|
|
'RF18 5390 0754 7034'
|
||
|
|
"""
|
||
|
|
|
||
|
|
from __future__ import annotations
|
||
|
|
|
||
|
|
from stdnum.exceptions import *
|
||
|
|
from stdnum.iso7064 import mod_97_10
|
||
|
|
from stdnum.util import clean
|
||
|
|
|
||
|
|
|
||
|
|
def compact(number: str) -> str:
|
||
|
|
"""Convert the number to the minimal representation. This strips the
|
||
|
|
number of any invalid separators and removes surrounding whitespace."""
|
||
|
|
return clean(number, ' -.,/:').upper().strip()
|
||
|
|
|
||
|
|
|
||
|
|
def validate(number: str) -> str:
|
||
|
|
"""Check if the number provided is a valid ISO 11649 structured creditor
|
||
|
|
reference number."""
|
||
|
|
number = compact(number)
|
||
|
|
if len(number) < 5 or len(number) > 25:
|
||
|
|
raise InvalidLength()
|
||
|
|
if not number.startswith('RF'):
|
||
|
|
raise InvalidFormat()
|
||
|
|
mod_97_10.validate(number[4:] + number[:4])
|
||
|
|
return number
|
||
|
|
|
||
|
|
|
||
|
|
def is_valid(number: str) -> bool:
|
||
|
|
"""Check if the number provided is a valid ISO 11649 structured creditor
|
||
|
|
number. This checks the length, formatting and check digits."""
|
||
|
|
try:
|
||
|
|
return bool(validate(number))
|
||
|
|
except ValidationError:
|
||
|
|
return False
|
||
|
|
|
||
|
|
|
||
|
|
def format(number: str) -> str:
|
||
|
|
"""Format the number provided for output.
|
||
|
|
|
||
|
|
Blocks of 4 characters, the last block can be less than 4 characters. See
|
||
|
|
https://www.paymentstandards.ch/dam/downloads/ig-qr-bill-en.pdf chapter
|
||
|
|
3.6.2.
|
||
|
|
"""
|
||
|
|
number = compact(number)
|
||
|
|
return ' '.join(number[i:i + 4] for i in range(0, len(number), 4))
|