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VAT number validation using VIES¶
The lino_xl.lib.vat plugin can use the VIES (VAT Information Exchange
System) service of the European
Union for validating VAT numbers stored in the
VatSubjectable.vat_id field.
Side note: Code snippets (lines starting with >>>) in this document get
tested as part of our development workflow. The following
initialization snippet tells you which demo project is being used in
this document.
>>> from lino import startup
>>> startup('lino_book.projects.cosi2.settings.doctests')
>>> from lino.api.doctest import *
The VAT number¶
Every business partner can have a VAT identification number (VATIN).
The following function validate_vat_id is used in this document to demonstrate the capabilities and roles of Lino in managing a VAT number.
>>> from django.core.exceptions import ValidationError
>>> def validate_vat_id(partner):
... try:
... partner.full_clean()
... print(partner.vat_id)
... except ValidationError as e:
... print("ValidationError:\n" + e.message)
A partner who has a vat_id (VAT number) field, by default
implementation, also has a vid_manager property, which is essentially a
pointer to an instance of a VatNumberManager that validates an inserted VAT
number and does some other things that we will see below.
Below example displays an error message for an invalid VAT number.
>>> Country = countries.Country
>>> Company = contacts.Company
>>> belgium = Country.objects.get(isocode="BE")
>>> obj = Company(name="foo", country=belgium)
>>> obj.vat_id = "5468523548"
>>> validate_vat_id(obj)
ValidationError:
Modulo 97 check failed for VAT identification number in BE
The validation error message is a little more self explanatory when the inserted VAT number does not match any format explained here. An example:
>>> obj = Company(name="bar Ltd.", vat_id="NL56465")
>>> validate_vat_id(obj)
ValidationError:
You have entered an invalid VAT identification number.
The general format follows: NLxxxxxxxxxBxx
Where each 'x' is a digit.
When the country field is empty, the ISO 3166-1-alpha-2 country code
must be given at the beginning of the VAT identification number otherwise lino
will treat the VAT identification number as a dummy and will not do any
validation check. The following example shows two possibilities where in first
case there’s no country associated with the partner but has a valid
vat_id format and in later case there’s no known country associated with
the partner not in country field neither in the vat_id. And
differences are distinguishable from the returned VAT number, where the
valid VAT number returns are formatted with dots (.) and a whitespace.
>>> obj = Company(name="foo Ltd.", vat_id="EE100041561")
>>> validate_vat_id(obj)
EE 100.041.561
>>> obj = Company(name="foo Inc.", vat_id="100041561")
>>> validate_vat_id(obj)
100041561
If the partner’s country is different from the country code given in the
VAT number, Lino will also raise a ValidationError.
>>> estonia = Country(isocode="EE")
>>> obj = Company(name="foo Inc.", country=estonia, vat_id="BE 100041561")
>>> validate_vat_id(obj)
ValidationError:
Country code (EE) does not match with BE.
By default a VatNumberManager instance includes the validation for
the countries with ISO code shown in the following code output.
>>> from lino_xl.lib.vat.choicelists import VAT_ORIGINS
>>> list(VAT_ORIGINS.keys())
['BE', 'AT', 'NL', 'HR', 'DK', 'EE', 'FI', 'FR', 'DE', 'EL', 'HU', 'IT', 'LV', 'LT', 'LU']
If the given country code is not included in the above example, Lino will accept any reasonable format of the VAT number as valid.
>>> obj = Company(name="HyD Inc.", vat_id="BD 545454656484b6563")
>>> validate_vat_id(obj)
BD 54.545.465.648.4B6.563
Adding a VatOrigin:
>>> from lino_xl.lib.vat.choicelists import VAT_ORIGINS, VatOrigin
>>> vo = VatOrigin('CY', 8, dummy_suffix="L",
... pattern="^(?P<country_code>CY) (?P<number>[0-9]{8})(?P<suffix>L)$")
>>> VAT_ORIGINS[vo.country_code] = vo
>>> validate_vat_id(Company(name="HyD Inc.", vat_id="CY 1234567890"))
ValidationError:
You have entered an invalid VAT identification number.
The general format follows: CYxxxxxxxxL
Where each 'x' is a digit.
>>> validate_vat_id(Company(name="HyD Inc.", vat_id="CY12345678L"))
CY 12.345.678L
When vat.use_online_check is True, the checkdata command
will do online verification of every VAT id.
- class lino_xl.lib.vat.VatIdChecker¶
Validate VAT id from online registry.
The demo database contains some fictive VAT ids that are syntactically correct but simply do not exist in reality.
Until 2022-12-28, Lino detected this as a data problem because
vat.use_online_check was True in lino_book.projects.cosi2.
That’s why we had a series of corresponding data problems. The following test is now skipped because
vat.use_online_check caused the test suite to break when the VIES
server was unavailable during inv prep.
>>> chk = checkdata.Checkers.get_by_value('vat.VatIdChecker')
>>> rt.show(checkdata.MessagesByChecker, chk)
...
+-------------------------+---------------------------------+------------------------------------------------------+
| Utilisateur responsable | Database object | Texte du message |
+=========================+=================================+======================================================+
| Robin Rood | *Bäckerei Ausdemwald* | Invalid VAT identification number BE 7088.996.857: |
| | | Not registered in BE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Bäckerei Mießen* | Invalid VAT identification number BE 4685.739.309: |
| | | Not registered in BE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Bäckerei Schmitz* | Invalid VAT identification number BE 4181.505.692: |
| | | Not registered in BE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Garage Mergelsberg* | Invalid VAT identification number BE 9045.438.159: |
| | | Not registered in BE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Donderweer BV* | Invalid VAT identification number NL 220.876.686B01: |
| | | Not registered in NL. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Van Achter NV* | Invalid VAT identification number NL 451.948.587B01: |
| | | Not registered in NL. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Hans Flott & Co* | Invalid VAT identification number DE 143.956.862: |
| | | Not registered in DE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Bernd Brechts Bücherladen* | Invalid VAT identification number DE 135.079.295: |
| | | Not registered in DE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Reinhards Baumschule* | Invalid VAT identification number DE 138.433.397: |
| | | Not registered in DE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Moulin Rouge* | Invalid VAT identification number FR 86.915.334.564: |
| | | Not registered in FR. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Auto École Verte* | Invalid VAT identification number FR 66.435.589.280: |
| | | Not registered in FR. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Maksu- ja Tolliamet* | Invalid VAT identification number EE 848.217.541: |
| | | Not registered in EE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Electrabel Customer Solutions* | Invalid VAT identification number BE 4018.258.949: |
| | | Not registered in BE. |
+-------------------------+---------------------------------+------------------------------------------------------+
| Robin Rood | *Leffin Electronics* | Invalid VAT identification number BE 0650.238.114: |
| | | Not registered in BE. |
+-------------------------+---------------------------------+------------------------------------------------------+