1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
# gstin.py - functions for handling Indian VAT numbers
#
# Copyright (C) 2021 Gaurav Chauhan
#
# 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
"""GSTIN (Goods and Services Tax identification number, Indian VAT number).
The Goods and Services Tax identification number (GSTIN) is a 15 digit unique
identifier assigned to all business entities in India registered under the
Goods and Services Tax (GST) Act, 2017.
Each GSTIN begins with a 2 digit state code, the next 10 characters are the
holder's PAN, the 13th character is an alphanumeric digit that represents the
number of GSTIN registrations made in a state or union territory for same the
PAN, the 14th character is 'Z' and the last character is an alphanumeric
check digit calculated using Luhn mod 36 algorithm.
More information:
* https://bajajfinserv.in/insights/what-is-goods-and-service-tax-identification-number
* https://ddvat.gov.in/docs/List%20of%20State%20Code.pdf
* https://en.wikipedia.org/wiki/Goods_and_Services_Tax_(India)
>>> validate('27AAPFU0939F1ZV')
'27AAPFU0939F1ZV'
>>> validate('27AAPFU0939F1Z')
Traceback (most recent call last):
...
InvalidLength: ...
>>> validate('369296450896540')
Traceback (most recent call last):
...
InvalidFormat: ...
>>> validate('27AAPFU0939F1AA')
Traceback (most recent call last):
...
InvalidComponent: ...
>>> validate('27AAPFU0939F1ZO')
Traceback (most recent call last):
...
InvalidChecksum: ...
>>> to_pan('27AAPFU0939F1ZV')
'AAPFU0939F'
>>> info('27AAPFU0939F1ZV')['state']
'Maharashtra'
"""
from __future__ import annotations
import re
from stdnum import luhn
from stdnum.exceptions import *
from stdnum.in_ import pan
from stdnum.util import clean
_GSTIN_RE = re.compile(r'^[0-9]{2}[A-Z]{5}[0-9]{4}[A-Z][0-9A-Z]{3}$')
_ALPHABET = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
_STATE_CODES = {
'01': 'Jammu and Kashmir',
'02': 'Himachal Pradesh',
'03': 'Punjab',
'04': 'Chandigarh',
'05': 'Uttarakhand',
'06': 'Haryana',
'07': 'Delhi',
'08': 'Rajasthan',
'09': 'Uttar Pradesh',
'10': 'Bihar',
'11': 'Sikkim',
'12': 'Arunachal Pradesh',
'13': 'Nagaland',
'14': 'Manipur',
'15': 'Mizoram',
'16': 'Tripura',
'17': 'Meghalaya',
'18': 'Assam',
'19': 'West Bengal',
'20': 'Jharkhand',
'21': 'Orissa',
'22': 'Chattisgarh',
'23': 'Madhya Pradesh',
'24': 'Gujarat',
'25': 'Daman and Diu',
'26': 'Dadar and Nagar Haveli',
'27': 'Maharashtra',
'28': 'Andhra Pradesh',
'29': 'Karnataka',
'30': 'Goa',
'31': 'Lakshadweep',
'32': 'Kerala',
'33': 'Tamil Nadu',
'34': 'Puducherry',
'35': 'Anadaman and Nicobar Islands',
'36': 'Telangana',
'37': 'Andhra Pradesh (New)',
}
def compact(number: str) -> str:
"""Convert the number to the minimal representation. This strips the
number of any valid separators and removes surrounding whitespace."""
return clean(number, ' -').upper().strip()
def validate(number: str) -> str:
"""Check if the number provided is a valid GSTIN. This checks the length,
formatting and check digit."""
number = compact(number)
if len(number) != 15:
raise InvalidLength()
if not _GSTIN_RE.match(number):
raise InvalidFormat()
if number[:2] not in _STATE_CODES or number[12] == '0' or number[13] != 'Z':
raise InvalidComponent()
pan.validate(number[2:12])
luhn.validate(number, _ALPHABET)
return number
def is_valid(number: str) -> bool:
"""Check if the number provided is a valid GSTIN. This checks the length,
formatting and check digit."""
try:
return bool(validate(number))
except ValidationError:
return False
def to_pan(number: str) -> str:
"""Convert the number to a PAN."""
number = compact(number)
return number[2:12]
def info(number: str) -> dict[str, str | int | None]:
"""Provide information that can be decoded locally from GSTIN (without
API)."""
number = validate(number)
return {
'state': _STATE_CODES.get(number[:2]),
'pan': number[2:12],
'holder_type': pan.info(number[2:12])['holder_type'],
'initial': number[6],
'registration_count': _ALPHABET.index(number[12]),
}
|
