rss-bridge/caches/SQLiteCache.php
Dag 0a118310cb
fix(sqlitecache): store blob as blob (#3555)
serialize() can return output with null bytes and other
non-text data. The prior behavior truncated data
which later results in unserialize() errors.

This happens when e.g. caching an object with a private field
or when caching e.g. a JPEG file (starts with 0xFFD8FFE1)

Fixes errors such as e.g.:

unserialize(): Error at offset 20 of 24 bytes at caches/SQLiteCache.php line 51
2023-07-20 19:11:13 +02:00

115 lines
3.5 KiB
PHP

<?php
class SQLiteCache implements CacheInterface
{
private \SQLite3 $db;
private string $scope;
private string $key;
private array $config;
public function __construct(array $config)
{
$default = [
'file' => null,
'timeout' => 5000,
'enable_purge' => true,
];
$config = array_merge($default, $config);
$this->config = $config;
if (!$config['file']) {
throw new \Exception('sqlite cache needs a file');
}
if (is_file($config['file'])) {
$this->db = new \SQLite3($config['file']);
$this->db->enableExceptions(true);
} else {
// Create the file and create sql schema
$this->db = new \SQLite3($config['file']);
$this->db->enableExceptions(true);
$this->db->exec("CREATE TABLE storage ('key' BLOB PRIMARY KEY, 'value' BLOB, 'updated' INTEGER)");
}
$this->db->busyTimeout($config['timeout']);
}
public function loadData(int $timeout = 86400)
{
$stmt = $this->db->prepare('SELECT value, updated FROM storage WHERE key = :key');
$stmt->bindValue(':key', $this->getCacheKey());
$result = $stmt->execute();
if (!$result) {
return null;
}
$row = $result->fetchArray(\SQLITE3_ASSOC);
if ($row === false) {
return null;
}
$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;
}
return $data;
}
// 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());
// $stmt->execute();
return null;
}
public function saveData($data): void
{
$blob = serialize($data);
$stmt = $this->db->prepare('INSERT OR REPLACE INTO storage (key, value, updated) VALUES (:key, :value, :updated)');
$stmt->bindValue(':key', $this->getCacheKey());
$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());
$result = $stmt->execute();
if ($result) {
$row = $result->fetchArray(\SQLITE3_ASSOC);
if ($row !== false) {
return $row['updated'];
}
}
return null;
}
public function purgeCache(int $timeout = 86400): void
{
if (!$this->config['enable_purge']) {
return;
}
$stmt = $this->db->prepare('DELETE FROM storage WHERE updated < :expired');
$stmt->bindValue(':expired', time() - $timeout);
$stmt->execute();
}
public function setScope(string $scope): void
{
$this->scope = $scope;
}
public function setKey(array $key): void
{
$this->key = json_encode($key);
}
private function getCacheKey()
{
return hash('sha1', $this->scope . $this->key, true);
}
}