From 143a4680e25ac4d46bb12bea7efcbef4f7480909 Mon Sep 17 00:00:00 2001
From: Joshua Ramon Enslin <joshua@museum-digital.de>
Date: Sat, 25 Sep 2021 21:56:01 +0200
Subject: [PATCH] Add validation function for phone numbers

---
 src/MD_STD_IN.php | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/MD_STD_IN.php b/src/MD_STD_IN.php
index 6e53a9f..d76c175 100644
--- a/src/MD_STD_IN.php
+++ b/src/MD_STD_IN.php
@@ -212,6 +212,27 @@ final class MD_STD_IN {
 
     }
 
+    /**
+     * Sanitizes and validates a phone number. An empty string passes.
+     *
+     * @param mixed $input Input string.
+     *
+     * @return string
+     */
+    public static function validate_phone_number(mixed $input):string {
+
+        if ($input === "") {
+            return "";
+        }
+
+        if (!preg_match("#^[()0-9/ +-]+$#", $input)) {
+            throw new MDgenericInvalidInputsException("Invalid phone number entered.");
+        }
+
+        return $input;
+
+    }
+
     /**
      * Sanitizes a string to a float.
      *