made Stud.IP cache compatible with PSR-6, re #3701

Merge request studip/studip!2570

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/classes/cache/KeyTrait.php b/lib/classes/cache/KeyTrait.php
new file mode 100644
index 0000000..021aaba
--- /dev/null
+++ b/lib/classes/cache/KeyTrait.php
@@ -0,0 +1,31 @@
+<?php
+namespace Studip\Cache;
+
+/**
+ * Trait for unique cache hashes per key for each system based on db configuration which should
+ * be sufficient to eliminate cache mishaps.
+ *
+ * @author      Jan-Hendrik Willms <tleilax+studip@gmail.com>
+ * @license     GPL2 or any later version
+ * @package     studip
+ * @subpackage  cache
+ * @since       Stud.IP 5.0
+ */
+trait KeyTrait
+{
+    protected ?string $cache_prefix = null;
+
+    /**
+     * Returns a prefix cache key based on db configuration.
+     *
+     * @param  string $offset
+     * @return string
+     */
+    protected function getCacheKey(string $offset): string
+    {
+        if ($this->cache_prefix === null) {
+            $this->cache_prefix = md5("{$GLOBALS['DB_STUDIP_HOST']}|{$GLOBALS['DB_STUDIP_DATABASE']}");
+        }
+        return "$this->cache_prefix/$offset";
+    }
+}