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| 1 | +# isni.py - functions for handling International Standard Name Identifiers |
| 2 | +# |
| 3 | +# Copyright (C) 2025 Arthur de Jong |
| 4 | +# |
| 5 | +# This library is free software; you can redistribute it and/or |
| 6 | +# modify it under the terms of the GNU Lesser General Public |
| 7 | +# License as published by the Free Software Foundation; either |
| 8 | +# version 2.1 of the License, or (at your option) any later version. |
| 9 | +# |
| 10 | +# This library is distributed in the hope that it will be useful, |
| 11 | +# but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | +# Lesser General Public License for more details. |
| 14 | +# |
| 15 | +# You should have received a copy of the GNU Lesser General Public |
| 16 | +# License along with this library; if not, write to the Free Software |
| 17 | +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 18 | +# 02110-1301 USA |
| 19 | + |
| 20 | +"""ISNI (International Standard Name Identifier). |
| 21 | +
|
| 22 | +The International Standard Name Identifier (ISNI) is used to identify |
| 23 | +contributors to media content such as books, television programmes, and |
| 24 | +newspaper articles. The number consists of 16 digits where the last character |
| 25 | +is a check digit. |
| 26 | +
|
| 27 | +More information: |
| 28 | +
|
| 29 | +* https://en.wikipedia.org/wiki/International_Standard_Name_Identifier |
| 30 | +* https://isni.org/ |
| 31 | +
|
| 32 | +>>> validate('0000 0001 2281 955X') |
| 33 | +'000000012281955X' |
| 34 | +>>> validate('0000 0001 1111 955X') |
| 35 | +Traceback (most recent call last): |
| 36 | + ... |
| 37 | +InvalidChecksum: ... |
| 38 | +>>> validate('0000 0001 2281') |
| 39 | +Traceback (most recent call last): |
| 40 | + ... |
| 41 | +InvalidLength: ... |
| 42 | +>>> format('000000012281955X') |
| 43 | +'0000 0001 2281 955X' |
| 44 | +""" |
| 45 | + |
| 46 | + |
| 47 | +from stdnum.exceptions import * |
| 48 | +from stdnum.iso7064 import mod_11_2 |
| 49 | +from stdnum.util import clean, isdigits |
| 50 | + |
| 51 | + |
| 52 | +def compact(number): |
| 53 | + """Convert the ISNI to the minimal representation. This strips the number |
| 54 | + of any valid ISNI separators and removes surrounding whitespace.""" |
| 55 | + return clean(number, ' -').strip().upper() |
| 56 | + |
| 57 | + |
| 58 | +def validate(number): |
| 59 | + """Check if the number is a valid ISNI. This checks the length and |
| 60 | + whether the check digit is correct.""" |
| 61 | + number = compact(number) |
| 62 | + if not isdigits(number[:-1]): |
| 63 | + raise InvalidFormat() |
| 64 | + if len(number) != 16: |
| 65 | + raise InvalidLength() |
| 66 | + mod_11_2.validate(number) |
| 67 | + return number |
| 68 | + |
| 69 | + |
| 70 | +def is_valid(number): |
| 71 | + """Check if the number provided is a valid ISNI.""" |
| 72 | + try: |
| 73 | + return bool(validate(number)) |
| 74 | + except ValidationError: |
| 75 | + return False |
| 76 | + |
| 77 | + |
| 78 | +def format(number): |
| 79 | + """Reformat the number to the standard presentation format.""" |
| 80 | + number = compact(number) |
| 81 | + return ' '.join((number[:4], number[4:8], number[8:12], number[12:16])) |
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