Merge branch 'main' into issue-3911issue-3911

1 files changed, 143 insertions, 0 deletions

diff --git a/lib/classes/cache/DbCache.php b/lib/classes/cache/DbCache.php
new file mode 100644
index 0000000..c7abef2
--- /dev/null
+++ b/lib/classes/cache/DbCache.php
@@ -0,0 +1,143 @@
+<?php
+
+namespace Studip\Cache;
+
+use DBManager;
+use Psr\Cache\CacheItemInterface;
+
+/**
+ * StudipCache implementation using database table
+ *
+ * @author    Elmar Ludwig <elmar.ludwig@uos.de>
+ */
+class DbCache extends Cache
+{
+    /**
+     * @return string A display name (that can be translated) for this cache class.
+     */
+    public static function getDisplayName(): string
+    {
+        return _('Datenbank');
+    }
+
+    /**
+     * Expire item from the cache.
+     *
+     * @param string $arg a single key
+     */
+    public function expire($arg)
+    {
+        $db = DBManager::get();
+
+        $stmt = $db->prepare('DELETE FROM cache WHERE cache_key = ?');
+        $stmt->execute([$arg]);
+    }
+
+    /**
+     * Expire all items from the cache.
+     */
+    public function flush()
+    {
+        $db = DBManager::get();
+
+        $db->exec('TRUNCATE TABLE cache');
+    }
+
+    /**
+     * Delete all expired items from the cache.
+     */
+    public function purge()
+    {
+        $db = DBManager::get();
+
+        $stmt = $db->prepare('DELETE FROM cache WHERE expires < ?');
+        $stmt->execute([time()]);
+    }
+
+    /**
+     * Return statistics.
+     *
+     * @return array|array[]
+     *@see Cache::getStats()
+     *
+     */
+    public function getStats(): array
+    {
+        return [
+            __CLASS__ => [
+                'name' => _('Anzahl Einträge'),
+                'value' => DBManager::get()->fetchColumn("SELECT COUNT(*) FROM `cache`")
+            ]
+        ];
+    }
+
+    /**
+     * Return the Vue component name and props that handle configuration.
+     *
+     * @return array
+     *@see Cache::getConfig()
+     *
+     */
+    public static function getConfig(): array
+    {
+        return [
+            'component' => null,
+            'props' => []
+        ];
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function getItem(string $key): CacheItemInterface
+    {
+        $query = "SELECT `content`, `expires`
+                  FROM `cache`
+                  WHERE `cache_key` = :key
+                    AND `expires` > UNIX_TIMESTAMP()";
+        $result = DBManager::get()->fetchOne($query, [':key' => $key]);
+
+        $item = new Item($key);
+        if (!empty($result)) {
+            $item->setHit();
+            if ($result['content']) {
+                $item->set(unserialize($result['content']));
+            }
+            if ($result['expires']) {
+                $expiration = new \DateTime();
+                $expiration->setTimestamp($result['expires']);
+                $item->expiresAt($expiration);
+            }
+        }
+        return $item;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function hasItem(string $key): bool
+    {
+        $query = "SELECT 1
+                  FROM `cache`
+                  WHERE `cache_key` = :key
+                    AND `expires` > UNIX_TIMESTAMP()";
+        return (bool) DBManager::get()->fetchColumn($query, [':key' => $key]);
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function save(CacheItemInterface $item): bool
+    {
+        $expiration = $this->getExpiration($item);
+        if ($expiration < 1) {
+            // The item would expire immediately.
+            return false;
+        }
+
+        return DBManager::get()->execute(
+            'REPLACE INTO `cache` VALUES (?, ?, ?)',
+            [$item->getKey(), serialize($item->get()), $expiration]
+        );
+    }
+}