From 89e06769f1103dc1c763103d4828f136adec8cec Mon Sep 17 00:00:00 2001
From: Joshua Ramon Enslin <joshua@museum-digital.de>
Date: Thu, 28 Jan 2021 21:47:59 +0100
Subject: [PATCH] Add class for validating color codes

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

diff --git a/MD_STD_IN.php b/MD_STD_IN.php
index e68c575..f2107cf 100644
--- a/MD_STD_IN.php
+++ b/MD_STD_IN.php
@@ -85,6 +85,27 @@ final class MD_STD_IN {
 
     }
 
+    /**
+     * String sanitization for 3 o4 6 characters RGB color codes (sans the leading #).
+     *
+     * @param mixed $input Input string.
+     *
+     * @return string
+     */
+    public static function sanitize_rgb_color($input):string {
+
+        $output = \filter_var($input,
+            FILTER_SANITIZE_STRING,
+            FILTER_FLAG_NO_ENCODE_QUOTES);
+
+        if (!(preg_match('/^[a-zA-Z0-9]{3}$/', $output)) && !(preg_match('/^[a-zA-Z0-9]{6}$/', $output))) {
+            throw new MDInvalidColorCode("Invalid color code provided: " . $output);
+        }
+
+        return $output;
+
+    }
+
     /**
      * Retrieves HTTP input texts from GET or POST variables, whatever is provided.
      * If neither is given, returns a provided default.