diff --git a/src/MD_STD_CACHE.php b/src/MD_STD_CACHE.php
index 87e03a1..e498252 100644
--- a/src/MD_STD_CACHE.php
+++ b/src/MD_STD_CACHE.php
@@ -55,18 +55,25 @@ final class MD_STD_CACHE {
      * Caches and serves a page through redis. Should be called at the start
      * of the script generating a page.
      *
-     * @param string  $redisKey Key to cache by in redis.
-     * @param integer $expiry   Expiration time in seconds.
+     * @param string     $redisKey Key to cache by in redis.
+     * @param integer    $expiry   Expiration time in seconds.
+     * @param Redis|null $redis    Redis connection already opened, if one exists.
+     *                             If this parameter is not provided, a separate
+     *                             redis connection is opened for this function.
      *
      * @return string
      */
-    public static function serve_page_through_redis_cache(string $redisKey, int $expiry = 3600):string {
+    public static function serve_page_through_redis_cache(string $redisKey, int $expiry = 3600, ?Redis $redis = null):string {
 
         if (PHP_SAPI === 'cli') {
             return '';
         }
 
-        $redis = self::open_redis_default();
+        if ($redis === null) {
+            $redis = self::open_redis_default();
+            $closeRedis = true;
+        }
+        else $closeRedis = false;
 
         if ($redis->ping() !== false) {
 
@@ -94,7 +101,10 @@ final class MD_STD_CACHE {
             }
 
         }
-        $redis->close();
+
+        if ($closeRedis === true) {
+            $redis->close();
+        }
 
         return '';