Validate WooCommerce customer email TLD

mu-plugins/woocommerce-customer-email-tld.php

@@ -0,0 +1,65 @@
+<?php
+
+/*
+ * Plugin Name: Validate WooCommerce customer email TLD
+ * Plugin URI: https://github.com/szepeviktor/wordpress-website-lifecycle
+ */
+
+/*
+wget -qO- "https://data.iana.org/TLD/tlds-alpha-by-domain.txt" | sed -e "1d;s#^\\(\\S\\+\\)\$#'\1',#" | paste -s -d ""
+*/
+const IANA_TLDS = [
+'COM',
+];
+
+add_filter(
+    'woocommerce_process_registration_errors',
+    static function($validation_error, $username, $password, $email) {
+        if (filter_var($email, FILTER_VALIDATE_EMAIL) === false) {
+            $validation_error->add('invalid_email', __('The provided email address is not valid', 'woocommerce'));
+            return $validation_error;
+        }
+
+        $domain = explode('@', $email, 2);
+        $parts = explode('.', idn_to_ascii($domain[1]));
+        $tld = array_pop($parts);
+        if (! in_array(strtoupper($tld), IANA_TLDS, true)) {
+            $validation_error->add('invalid_email_domain', __('The provided email address is not valid', 'woocommerce'));
+        }
+        return $validation_error;
+    },
+    20,
+    4
+);
+
+add_action(
+    'woocommerce_after_checkout_validation',
+    static function ($data, $errors) {
+        if (filter_var($data['billing_email'], FILTER_VALIDATE_EMAIL) === false) {
+            $errors->add('invalid_email', __('The provided email address is not valid', 'woocommerce'));
+            return;
+        }
+
+        $domain = explode('@', $data['billing_email'], 2);
+        $parts = explode('.', idn_to_ascii($domain[1]));
+        $tld = array_pop($parts);
+        if (! in_array(strtoupper($tld), IANA_TLDS, true)) {
+            $errors->add('invalid_email_domain', __('The provided email address is not valid', 'woocommerce'));
+        }
+    },
+    20,
+    2
+);
+
+/* Alternative to woocommerce_after_checkout_validation
+add_action(
+    'woocommerce_checkout_process',
+    static function () {
+        $email = filter_input(INPUT_POST, 'billing_email', FILTER_VALIDATE_EMAIL);
+
+        wc_add_notice(__('The provided email address is not valid', 'woocommerce'), 'error');
+    },
+    20,
+    0
+);
+*/