INTL_IDNA_VARIANT_UTS46 is not supported on all systems (#173)

* INTL_IDNA_VARIANT_UTS46 is not supported on all systems

Fall back to INTL_IDNA_VARIANT_2003 if INTL_IDNA_VARIANT_UTS46 is not found.

* Fix syntax error

* Update DNSCheckValidation.php

EmailValidator/Validation/DNSCheckValidation.php

@@ -18,6 +18,13 @@ class DNSCheckValidation implements EmailValidation
      * @var InvalidEmail
      */
     private $error;
+    
+    public function __construct()
+    {
+        if (!extension_loaded('intl')) {
+            throw new \LogicException(sprintf('The %s class requires the Intl extension.', __CLASS__));
+        }
+    }
 
     public function isValid($email, EmailLexer $emailLexer)
     {
@@ -44,7 +51,11 @@ class DNSCheckValidation implements EmailValidation
 
     protected function checkDNS($host)
     {
-        $host = rtrim(idn_to_ascii($host, IDNA_DEFAULT, INTL_IDNA_VARIANT_UTS46), '.') . '.';
+        $variant = INTL_IDNA_VARIANT_2003;
+        if ( defined('INTL_IDNA_VARIANT_UTS46') ) {
+            $variant = INTL_IDNA_VARIANT_UTS46;
+        }
+        $host = rtrim(idn_to_ascii($host, IDNA_DEFAULT, $variant), '.') . '.';
 
         $Aresult = true;
         $MXresult = checkdnsrr($host, 'MX');

EmailValidator/Validation/SpoofCheckValidation.php

@@ -16,7 +16,7 @@ class SpoofCheckValidation implements EmailValidation
 
     public function __construct()
     {
-        if (!class_exists(Spoofchecker::class)) {
+        if (!extension_loaded('intl')) {
             throw new \LogicException(sprintf('The %s class requires the Intl extension.', __CLASS__));
         }
     }

README.md

@@ -6,7 +6,7 @@ With the help of [PHPStorm](https://www.jetbrains.com/phpstorm/)
 ## Requirements ##
 
  * [Composer](https://getcomposer.org) is required for installation
- * [Spoofchecking](https://github.com/egulias/EmailValidator/blob/master/EmailValidator/Validation/SpoofCheckValidation.php) validation requires that your PHP system have the [PHP Internationalization Libraries](https://php.net/manual/en/book.intl.php) (also known as PHP Intl)
+ * [Spoofchecking](https://github.com/egulias/EmailValidator/blob/master/EmailValidator/Validation/SpoofCheckValidation.php) and [DNSCheckValidation](https://github.com/egulias/EmailValidator/blob/master/EmailValidator/Validation/DNSCheckValidation.php) validation requires that your PHP system have the [PHP Internationalization Libraries](https://php.net/manual/en/book.intl.php) (also known as PHP Intl)
 
 ## Installation ##