Support for generating IBANs for countries when bban doesn't start with bank_code

[sedlar]

It's not possible to generate IBAN for countries where bban doesn't start with bank_code, e.g. Italy - http://www.xe.com/ibancalculator/sample/?ibancountry=italy

Do you intend to support generating ibans for all countries?

On [9]: iban = IBAN('IT60 X054 2811 1010 0000 0123 456')                                          

In [10]: iban.country_code
Out[10]: 'IT'

In [11]: iban.bank_code
Out[11]: '05428'

In [12]: iban.account_code
Out[12]: '000000123456'

In [13]: iban.branch_code
Out[13]: '11101'

In [14]: IBAN.generate(country_code=iban.country_code, bank_code=iban.bank_code+iban.branch_code, account_code=iban.account_code)
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-14-4145eaaa1945> in <module>()
----> 1 IBAN.generate(country_code=iban.country_code, bank_code=iban.bank_code+iban.branch_code, account_code=iban.account_code)

~/.virtualenvs/swift/lib/python3.5/site-packages/schwifty/iban.py in generate(cls, country_code, bank_code, account_code)
    111         account_code = account_code.rjust(account_code_length, '0')
    112         iban = country_code + '??' + bank_code + account_code
--> 113         return cls(iban)
    114 
    115     def validate(self):

~/.virtualenvs/swift/lib/python3.5/site-packages/schwifty/iban.py in __init__(self, iban, allow_invalid)
     67 
     68         if not allow_invalid:
---> 69             self.validate()
     70 
     71     def _calc_checksum_digits(self):

~/.virtualenvs/swift/lib/python3.5/site-packages/schwifty/iban.py in validate(self)
    115     def validate(self):
    116         self._validate_characters()
--> 117         self._validate_length()
    118         self._validate_format()
    119         self._validate_checksum()

~/.virtualenvs/swift/lib/python3.5/site-packages/schwifty/iban.py in _validate_length(self)
    130     def _validate_length(self):
    131         if self.spec['iban_length'] != self.length:
--> 132             raise ValueError("Invalid IBAN length")
    133 
    134     def _validate_format(self):

ValueError: Invalid IBAN length

[mdomke]

Hey @sedlar, sorry for the late reply. This is actually a bug in schwifty, because the IBAN.generate-method cannot handle IBANs which are composed of other things than country-code, check-sum, bank-code, branch-code and account-code. The italian BBANs have a format specification that looks like this 1!a5!n5!n12!c. So there seems to be one character prefixed to the BBAN which I don't know the meaning of. Is it static? Is it always X. Can you maybe shed some light on this?

[sedlar]

Hi @mdomke, thanks for reply. The X character is national checksum digit. I have found the description of the algorithm to compute it in https://docs.oracle.com/cd/E18727_01/doc.121/e13483/T359831T498954.htm. Descriptions of some other country specific checksum can be found also in globalcitizen/php-iban#39.

[mdomke]

Hi @sedlar thank you for the information. I'll try and see if I can implement something with respect to country specific check digits, but I can't promise anything time wise.

[giuseppecot]

Hi, for IBAN IT there is an error in the 'iban_registry.json' file, that is:
"IT": {
     "iban_spec": "IT2! n1! a5! n5! n12! c",
     "iban_length": 27,
     "bban_length": 23,
     "bban_spec": "1! a5! n5! n12! c",
     "positions": {
       "branch_code": [
         6
         11
       ]
       "account_code": [
         11
         23
       ]
       "bank_code": [
         0,
         6
       ]
     }
   }

referring to wikipedia
the bank_code cpm takes the CIN, so the index was modified to include the character 0.

in this way the problem has been solved.

[mdomke]

This is fixed by #26