valvat
===========

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Validates european vat numbers. Standalone or as a ActiveModel validator.

## Features

* Simple syntax verification
* Lookup via the VIES web service
* ActiveModel/Rails integration
* Works standalone without ActiveModel
* I18n locales for language specific error messages in English, German, French, Spanish, Italian, Portuguese, Polish, Swedish, Dutch, Danish, Czech, Slovakian, Hungarian, Bulgarian, Romanian, Latvian, Catalan, and Finnish.
* *Experimental* checksum verification

valvat is tested and works with ruby MRI 1.9.3/2.0/2.1/2.2/2.3/2.4, jruby (in 1.9 mode) and ActiveModel 3/4/5

## Installation

Add it to your Gemfile:

    gem 'valvat'

To save most of the used memory and load only the local verification functionality – and not the remote lookup with VIES – add it like this instead:

    gem 'valvat', :require => 'valvat/local'

In any case run:

    $ bundle

Or install it yourself as:

    $ gem install valvat

## Basic Usage

To verify the syntax of a vat number:

    Valvat.new("DE345789003").valid?
    => true or false

To check if the given vat number exists via the VIES web service:

    Valvat.new("DE345789003").exists?
    => true or false or nil

*IMPORTANT* Keep in mind that the VIES web service might be offline at some time for some countries. If this happens `exists?` or `Valvat::Lookup.validate` will return `nil`.

Visit [http://ec.europa.eu/taxation_customs/vies/viesspec.do](http://ec.europa.eu/taxation_customs/vies/viesspec.do) for more accurate information at what time the service for a specific country will be down.

It is also possible to bypass initializing a Valvat instance and check the syntax of a var number string directly with:

    Valvat::Syntax.validate("DE345789003")
    => true or false

Or to lookup a vat number string directly via VIES web service:

    Valvat::Lookup.validate("DE345789003")
    => true or false or nil

## Experimental checksum verification

valvat allows to check vat numbers from AT, BE, BG, DE, DK, ES, FR, FI, GR, IE, IT, LU, NL, PL, PT, SE and SI against a checksum calculation. All other countries will fall back to a simple syntax check:

    Valvat.new("DE345789003").valid_checksum?
    => true or false

These results are more valuable than a simple syntax check, but keep in mind: they can not replace a lookup via VIES.

*IMPORTANT* This feature was tested against all vat numbers I could get my hand on, but it is still marked as *experimental* because these calculations are not documented and may return wrong results.

To bypass initializing a Valvat instance:

    Valvat::Checksum.validate("DE345789003")
    => true or false

## Details & request identifier

If you need all details and not only if the VAT is valid, pass {:detail => true} as second parameter to the lookup call.

    Valvat.new("IE6388047V").exists?(:detail => true)
    => {
      :country_code=>"IE", :vat_number => "6388047V",
      :request_date => Date.today, :name=>"GOOGLE IRELAND LIMITED",
      :address=>"1ST & 2ND FLOOR ,GORDON HOUSE ,BARROW STREET ,DUBLIN 4"
    } or false or nil

According to EU law, or at least as Austria sees it, it's mandatory to verify the UID number of every new customer, but also to check the UID Number periodicaly. To prove that you have checked the UID number, the VIES Web service can return a requestIdentifier.

To receive a requestIdentifier you need to pass your own VAT number in the options hash. In this Example, Google (VAT IE6388047V) is checking the validity of eBays VAT number (LU21416127)

    Valvat.new("LU21416127").exists?(:requester_vat => "IE6388047V")
    => {
      :country_code=>"LU", :vat_number => "21416127",
      :request_date => Date.today, :name=>"EBAY EUROPE S.A R.L.",
      :address => "22, BOULEVARD ROYAL\nL-2449  LUXEMBOURG",
      :company_type => nil, :request_identifier => "some_uniq_string"
    } or false or nil

## Usage with ActiveModel / Rails 3

### Loading

When the valvat gem is required and ActiveModel is already loaded, everything will work fine out of the box. If your load order differs just add

    require 'active_model/validations/valvat_validator'

after ActiveModel has been loaded.

### Simple syntax validation

To validate the attribute `vat_number` add this to your model:

    class MyModel < ActiveRecord::Base
      validates :vat_number, :valvat => true
    end

### Additional lookup validation

To additionally perform a lookup via VIES:

    validates :vat_number, :valvat => {:lookup => true}

By default this will validate to true if the VIES web service is down. To fail in this case simply add the `:fail_if_down` option:

    validates :vat_number, :valvat => {:lookup => :fail_if_down}

### Additional (and experimental) checksum validation

To additionally perform a checksum validation:

    validates :vat_number, :valvat => {:checksum => true}

### Additional ISO country code validation

If you want the vat number’s (ISO) country to match another country attribute, use the _match_country_ option:

    validates :vat_number, :valvat => {:match_country => :country}

where it is supposed that your model has a method named _country_ which returns the country ISO code you want to match.

### Allow blank

By default blank vat numbers validate to false. To change this add the `:allow_blank` option:

    validates :vat_number, :valvat => {:allow_blank => true}

### Allow vat numbers outside of europe

To allow vat numbers from outside of europe, add something like this to your model (country_code should return a upcase ISO country code):

    class MyModel < ActiveRecord::Base
      validates :vat_number, :valvat => true, :if => :eu?

      def eu?
        Valvat::Utils::EU_COUNTRIES.include?(country_code)
      end
    end

## Utilities

To split a vat number into the country code and the remaining chars:

    Valvat::Utils.split("ATU345789003")
    => ["AT", "U345789003"]

or

    Valvat.new("ATU345789003").to_a
    => ["AT", "U345789003"]

Both methods always return an array. If it can not detect the country or the given country is located outside of europe it returns `[nil, nil]`. Please note that this does not strictly return the ISO country code: for greek vat numbers this returns the ISO language code 'EL' instead of the ISO country code 'GR'.

To extract the ISO country code of a given vat number:

    Valvat.new("EL7345789003").iso_country_code
    => "GR"

To extract the vat country code (first two chars in every european vat number):

    Valvat.new("EL7345789003").vat_country_code
    => "EL"

To normalize a vat number:

    Valvat::Utils.normalize("atu345789003")
    => "ATU345789003"

This basically just removes trailing spaces and ensures all chars are uppercase.

## Usage with IPv6

There seems to be a problem when using the VIES service over IPv6. Sadly this is nothing this gem can address. For details and proposed solutions have a look at [this question on StackOverflow](http://stackoverflow.com/questions/15616833/vies-vat-api-soap-error-ipv6). Thanks to George Palmer for bringing up this issue.

## Links

* [VIES web service](http://ec.europa.eu/taxation_customs/vies)
* [European vat number formats (german)](http://bzst.de/DE/Steuern_International/USt_Identifikationsnummer/Merkblaetter/Aufbau_USt_IdNr.html)
* [European vat number formats on Wikipedia](http://en.wikipedia.org/wiki/European_Union_Value_Added_Tax)

## Contributions by

* [ndnenkov](https://github.com/ndnenkov)
* [0ctobat](https://github.com/0ctobat)
* [kaapa](https://github.com/kaapa)
* [descala](https://github.com/descala)
* [Carlos Hernández Medina](https://github.com/polimorfico)
* [Julik Tarkhanov](https://github.com/julik)
* [Roman Lehnert](https://github.com/romanlehnert)
* [0scarius](https://github.com/0scarius)
* [Davidslv](https://github.com/Davidslv)
* [brianphillips](https://github.com/brianphillips)
* [wasi](https://github.com/wasi)
* [liggitt](https://github.com/liggitt)
* [nevesenin](https://github.com/nevesenin)
* [shaundaley39](https://github.com/shaundaley39)
* [lcx](https://github.com/lcx)
* [kirichkov](https://github.com/kirichkov)
* [borodiychuk](https://github.com/borodiychuk)
* [opsidao](https://github.com/opsidao)
* [henrik](https://github.com/henrik)
* [SpoBo](https://github.com/SpoBo)
* [Deb Bassett](https://github.com/urbanwide)

## BlaBla

Copyright (c) 2011-2017 Yolk Sebastian Munz & Julia Soergel GbR

Beyond that, the implementation is licensed under the MIT License.