Add direct validation function for noda mail checker

src/NodaMailChecker.php

@@ -107,4 +107,26 @@ final class NodaMailChecker {
         return self::validateMailDomainAccessibilityCached($mysqli, $domain);
 
     }
+
+    /**
+     * Validates mail address, throwing an exception if the mail address is not valid.
+     *
+     * @param MDMysqli $mysqli       DB connection.
+     * @param string   $mail_address Address.
+     *
+     * @return string
+     */
+    public static function validateMail(MDMysqli $mysqli, string $mail_address):string {
+
+        if (empty($mail_address)) return $mail_address;
+
+        $mail_address = MD_STD_IN::sanitize_email($mail_address);
+
+        if (self::validateMailByDomainAccessibilityCached($mysqli, $mail_address) === false) {
+            throw new MDInvalidEmail("The host name of the entered mail address is invalid");
+        }
+
+        return $mail_address;
+
+    }
 }