feat: validate EU VAT ID (#2)

README.md

@@ -8,6 +8,10 @@ App to hold regional code for Germany, built on top of ERPNext.
 
     ![Section with Register Information](docs/register_information.png)
 
+- Validation of EU VAT IDs
+
+    <video src="docs/validate_vat_id.webm" autoplay loop>Validate EU VAT ID</video>
+
 ## Installation
 
 ### On Frappe Cloud

erpnext_germany/api.py

@@ -0,0 +1,20 @@
+import frappe
+
+
+@frappe.whitelist()
+def validate_vat_id(vat_id: str) -> bool:
+	"""Use the EU VAT checker to validate a VAT ID."""
+	from .utils.eu_vat import is_valid_eu_vat_id
+
+	result = frappe.cache().hget("eu_vat_validation", vat_id, shared=True)
+	if result is not None:
+		return result
+
+	try:
+		result = is_valid_eu_vat_id(vat_id)
+		frappe.cache().hset("eu_vat_validation", vat_id, result, shared=True)
+	except Exception:
+		frappe.response["status_code"] = 501
+		result = None
+
+	return result

erpnext_germany/hooks.py

@@ -1,7 +1,6 @@
 from . import __version__ as app_version
 from .constants import REGISTER_COURTS
 
-
 app_name = "erpnext_germany"
 app_title = "ERPNext Germany"
 app_publisher = "ALYF GmbH"
@@ -17,7 +16,7 @@
 
 # include js, css files in header of desk.html
 # app_include_css = "/assets/erpnext_germany/css/erpnext_germany.css"
-# app_include_js = "/assets/erpnext_germany/js/erpnext_germany.js"
+app_include_js = "/assets/erpnext_germany/js/validate_vat_id.js"
 
 # include js, css files in header of web template
 # web_include_css = "/assets/erpnext_germany/css/erpnext_germany.css"
@@ -34,7 +33,10 @@
 # page_js = {"page" : "public/js/file.js"}
 
 # include js in doctype views
-# doctype_js = {"doctype" : "public/js/doctype.js"}
+doctype_js = {
+	"Customer": "public/js/customer.js",
+	"Supplier": "public/js/supplier.js",
+}
 # doctype_list_js = {"doctype" : "public/js/doctype_list.js"}
 # doctype_tree_js = {"doctype" : "public/js/doctype_tree.js"}
 # doctype_calendar_js = {"doctype" : "public/js/doctype_calendar.js"}

erpnext_germany/public/js/customer.js

@@ -0,0 +1,5 @@
+frappe.ui.form.on("Customer", {
+	setup: function (frm) {
+		erpnext_germany.utils.setup_vat_id_validation_button(frm);
+	}
+});

erpnext_germany/public/js/supplier.js

@@ -0,0 +1,5 @@
+frappe.ui.form.on("Supplier", {
+	setup: function (frm) {
+		erpnext_germany.utils.setup_vat_id_validation_button(frm);
+	}
+});

erpnext_germany/public/js/validate_vat_id.js

@@ -0,0 +1,51 @@
+
+frappe.provide("erpnext_germany.utils");
+
+erpnext_germany.utils.setup_vat_id_validation_button = function (frm) {
+	const $wrapper = $(frm.fields_dict.tax_id.input_area);
+	const $link_button = $(
+		`<span class="link-btn"
+			style="top: 2px; right: 2px;"
+		>
+            <a
+				class="btn btn-xs btn-default"
+				title="${__("Validate EU VAT ID")}"
+				style="padding: 3px;"
+			>
+                ${frappe.utils.icon("search", "sm")}
+            </a>
+        </span>`
+	);
+
+	$($wrapper).append($link_button);
+	$link_button.toggle(true);
+	$link_button.on("click", "a", () => {
+		const vat_id = frm.doc.tax_id;
+		erpnext_germany.utils.check_vat_id(vat_id)
+			.then((is_valid) => {
+				if (is_valid === true) {
+					frappe.show_alert({
+						message: __("Tax ID is a valid EU VAT ID"),
+						indicator: "green",
+					});
+				} else if (is_valid === false) {
+					frappe.show_alert({
+						message: __("Tax ID is not a valid EU VAT ID"),
+						indicator: "red",
+					});
+				} else {
+					frappe.show_alert({
+						message: __("Tax ID could not be validated"),
+						indicator: "grey",
+					});
+				}
+			});
+	});
+};
+
+erpnext_germany.utils.check_vat_id = function (vat_id) {
+	return frappe.xcall(
+		"erpnext_germany.api.validate_vat_id",
+		{ vat_id: vat_id },
+	);
+};

erpnext_germany/translations/de.csv

@@ -1,3 +1,7 @@
 Register Type,Registerart
 Register Number,Registernummer
 Register Court,Registergericht
+Validate EU VAT ID,Ust-IdNr. validieren
+Tax ID is a valid EU VAT ID,Steuernummer ist gültige Ust-IdNr.
+Tax ID is not a valid EU VAT ID,Steuernummer ist keine gültige Ust-IdNr.
+Tax ID could not be validated,Steuernummer konnte nicht validiert werden.

erpnext_germany/utils/eu_vat.py

@@ -0,0 +1,12 @@
+import zeep
+
+
+def is_valid_eu_vat_id(vat_id) -> bool:
+	"""Use the EU VAT checker to validate a VAT ID."""
+	country_code = vat_id[:2].upper()
+	vat_number = vat_id[2:].replace(" ", "")
+
+	client = zeep.Client("https://ec.europa.eu/taxation_customs/vies/checkVatService.wsdl")
+	result = client.service.checkVat(vatNumber=vat_number, countryCode=country_code)
+
+	return result.valid

erpnext_germany/utils/test_utils.py

@@ -0,0 +1,21 @@
+from unittest import TestCase
+from .eu_vat import is_valid_vat_id
+
+
+class TestUtils(TestCase):
+	def test_validate_vat_id(self):
+		valid_ids = [
+			"DE329035522", # ALYF
+			"DE210157578", # SAP
+		]
+		invalid_ids = [
+			"ABC123",
+			"Test Test",
+			"DE1234567890",
+		]
+
+		for vat_id in valid_ids:
+			self.assertTrue(is_valid_vat_id(vat_id))
+
+		for vat_id in invalid_ids:
+			self.assertFalse(is_valid_vat_id(vat_id))