use session.gc_maxlifetime for session storage in cache, fixes #604

Closes #604

Merge request studip/studip!1786

lib/phplib/CT_Cache.class.php

@@ -5,52 +5,64 @@
 ## PHPLIB Data Storage Container using Stud.IP cache
 ## for use with Stud.IP and cache only!
 
-class CT_Cache {
-    const CACHE_KEY_PREFIX = 'session_data';
-    const SESSION_LIFETIME = 7200;
+class CT_Cache
+{
+    protected const CACHE_KEY_PREFIX = 'session_data';
+    protected const SESSION_LIFETIME = 7200;
 
     private $cache;
 
-    function ac_start() {
+    public function ac_start()
+    {
         $this->cache = StudipCacheFactory::getCache();
     }
 
-    function ac_get_lock() {
+    public function ac_get_lock()
+    {
     }
 
-    function ac_release_lock() {
+    public function ac_release_lock()
+    {
     }
 
-    function ac_newid($str, $name = null) {
+    public function ac_newid($str, $name = null)
+    {
         return $this->ac_get_value($str) === false ? $str : false;
     }
 
-    function ac_store($id, $name, $str) {
+    public function ac_store($id, $name, $str)
+    {
         $cache_key = self::CACHE_KEY_PREFIX . '/' . $id;
-        return $this->cache->write($cache_key, $str, self::SESSION_LIFETIME);
+        return $this->cache->write($cache_key, $str, ini_get('session.gc_maxlifetime') ?: self::SESSION_LIFETIME);
     }
 
-    function ac_delete($id, $name = null) {
+    public function ac_delete($id, $name = null)
+    {
         $cache_key = self::CACHE_KEY_PREFIX . '/' . $id;
         $this->cache->expire($cache_key);
     }
 
-    function ac_gc($gc_time, $name = null) {
+    public function ac_gc($gc_time, $name = null)
+    {
     }
 
-    function ac_halt($s) {
+    public function ac_halt($s)
+    {
         echo "<b>$s</b>";
         exit;
     }
 
-    function ac_get_value($id, $name = null) {
+    public function ac_get_value($id, $name = null)
+    {
         $cache_key = self::CACHE_KEY_PREFIX . '/' . $id;
         return $this->cache->read($cache_key);
     }
 
-    function ac_get_changed($id, $name = null) {
+    public function ac_get_changed($id, $name = null)
+    {
     }
 
-    function ac_set_changed($id, $name, $timestamp) {
+    public function ac_set_changed($id, $name, $timestamp)
+    {
     }
 }