fix: rewrite and improve caching (#3594)

caches/SQLiteCache.php

@@ -1,10 +1,10 @@
 <?php
 
+declare(strict_types=1);
+
 class SQLiteCache implements CacheInterface
 {
     private \SQLite3 $db;
-    private string $scope;
-    private string $key;
     private array $config;
 
     public function __construct(array $config)
@@ -31,85 +31,77 @@ class SQLiteCache implements CacheInterface
             $this->db->exec("CREATE TABLE storage ('key' BLOB PRIMARY KEY, 'value' BLOB, 'updated' INTEGER)");
         }
         $this->db->busyTimeout($config['timeout']);
+        // https://www.sqlite.org/pragma.html#pragma_journal_mode
+        $this->db->exec('PRAGMA journal_mode = wal');
+        // https://www.sqlite.org/pragma.html#pragma_synchronous
+        $this->db->exec('PRAGMA synchronous = NORMAL');
     }
 
-    public function loadData(int $timeout = 86400)
+    public function get(string $key, $default = null)
     {
+        $cacheKey = $this->createCacheKey($key);
         $stmt = $this->db->prepare('SELECT value, updated FROM storage WHERE key = :key');
-        $stmt->bindValue(':key', $this->getCacheKey());
+        $stmt->bindValue(':key', $cacheKey);
         $result = $stmt->execute();
         if (!$result) {
-            return null;
+            return $default;
         }
         $row = $result->fetchArray(\SQLITE3_ASSOC);
         if ($row === false) {
-            return null;
+            return $default;
         }
-        $value = $row['value'];
-        $modificationTime = $row['updated'];
-        if (time() - $timeout < $modificationTime) {
-            $data = unserialize($value);
-            if ($data === false) {
-                Logger::error(sprintf("Failed to unserialize: '%s'", mb_substr($value, 0, 100)));
-                return null;
+        $expiration = $row['updated'];
+        if ($expiration === 0 || $expiration > time()) {
+            $blob = $row['value'];
+            $value = unserialize($blob);
+            if ($value === false) {
+                Logger::error(sprintf("Failed to unserialize: '%s'", mb_substr($blob, 0, 100)));
+                // delete?
+                return $default;
             }
-            return $data;
+            return $value;
         }
-        // It's a good idea to delete expired cache items.
-        // However I'm seeing lots of  SQLITE_BUSY errors so commented out for now
-        // $stmt = $this->db->prepare('DELETE FROM storage WHERE key = :key');
-        // $stmt->bindValue(':key', $this->getCacheKey());
-        // $stmt->execute();
-        return null;
+        // delete?
+        return $default;
     }
-
-    public function saveData($data): void
+    public function set(string $key, $value, int $ttl = null): void
     {
-        $blob = serialize($data);
-
+        $cacheKey = $this->createCacheKey($key);
+        $blob = serialize($value);
+        $expiration = $ttl === null ? 0 : time() + $ttl;
         $stmt = $this->db->prepare('INSERT OR REPLACE INTO storage (key, value, updated) VALUES (:key, :value, :updated)');
-        $stmt->bindValue(':key', $this->getCacheKey());
+        $stmt->bindValue(':key', $cacheKey);
         $stmt->bindValue(':value', $blob, \SQLITE3_BLOB);
-        $stmt->bindValue(':updated', time());
-        $stmt->execute();
-    }
-
-    public function getTime(): ?int
-    {
-        $stmt = $this->db->prepare('SELECT updated FROM storage WHERE key = :key');
-        $stmt->bindValue(':key', $this->getCacheKey());
+        $stmt->bindValue(':updated', $expiration);
         $result = $stmt->execute();
-        if ($result) {
-            $row = $result->fetchArray(\SQLITE3_ASSOC);
-            if ($row !== false) {
-                return $row['updated'];
-            }
-        }
-        return null;
+        // Unclear whether we should $result->finalize(); here?
     }
 
-    public function purgeCache(int $timeout = 86400): void
+    public function delete(string $key): void
+    {
+        $key = $this->createCacheKey($key);
+        $stmt = $this->db->prepare('DELETE FROM storage WHERE key = :key');
+        $stmt->bindValue(':key', $key);
+        $result = $stmt->execute();
+    }
+
+    public function prune(): void
     {
         if (!$this->config['enable_purge']) {
             return;
         }
-        $stmt = $this->db->prepare('DELETE FROM storage WHERE updated < :expired');
-        $stmt->bindValue(':expired', time() - $timeout);
-        $stmt->execute();
+        $stmt = $this->db->prepare('DELETE FROM storage WHERE updated <= :now');
+        $stmt->bindValue(':now', time());
+        $result = $stmt->execute();
     }
 
-    public function setScope(string $scope): void
+    public function clear(): void
     {
-        $this->scope = $scope;
+        $this->db->query('DELETE FROM storage');
     }
 
-    public function setKey(array $key): void
+    private function createCacheKey($key)
     {
-        $this->key = json_encode($key);
-    }
-
-    private function getCacheKey()
-    {
-        return hash('sha1', $this->scope . $this->key, true);
+        return hash('sha1', $key, true);
     }
 }