rss-bridge/caches/SQLiteCache.php
fulmeek 21d3bf3b60 caches: Refactor the API (#1060)
- For consistency, functions should always return null on non-existing data.

- WordPressPluginUpdateBridge appears to have used its own cache instance in the past. Obviously not used anymore.

- Since $key can be anything, the cache implementation must ensure to assign the related data reliably; most commonly by serializing and hashing the key in an appropriate way.

- Even though the default path for storage is perfectly fine, some people may want to use a different location. This is an example how a cache implementation is responsible for its requirements.
2019-04-29 20:12:43 +02:00

121 lines
3 KiB
PHP

<?php
/**
* Cache based on SQLite 3 <https://www.sqlite.org>
*/
class SQLiteCache implements CacheInterface {
protected $scope;
protected $key;
private $db = null;
public function __construct() {
if (!extension_loaded('sqlite3')) {
die('"sqlite3" extension not loaded. Please check "php.ini"');
}
$file = Configuration::getConfig(get_called_class(), 'file');
if (empty($file)) {
die('Configuration for ' . get_called_class() . ' missing. Please check your config.ini.php');
}
if (dirname($file) == '.') {
$file = PATH_CACHE . $file;
} elseif (!is_dir(dirname($file))) {
die('Invalid configuration for ' . get_called_class() . '. Please check your config.ini.php');
}
if (!is_file($file)) {
$this->db = new SQLite3($file);
$this->db->enableExceptions(true);
$this->db->exec("CREATE TABLE storage ('key' BLOB PRIMARY KEY, 'value' BLOB, 'updated' INTEGER)");
} else {
$this->db = new SQLite3($file);
$this->db->enableExceptions(true);
}
$this->db->busyTimeout(5000);
}
public function loadData(){
$Qselect = $this->db->prepare('SELECT value FROM storage WHERE key = :key');
$Qselect->bindValue(':key', $this->getCacheKey());
$result = $Qselect->execute();
if ($result instanceof SQLite3Result) {
$data = $result->fetchArray(SQLITE3_ASSOC);
if (isset($data['value'])) {
return unserialize($data['value']);
}
}
return null;
}
public function saveData($data){
$Qupdate = $this->db->prepare('INSERT OR REPLACE INTO storage (key, value, updated) VALUES (:key, :value, :updated)');
$Qupdate->bindValue(':key', $this->getCacheKey());
$Qupdate->bindValue(':value', serialize($data));
$Qupdate->bindValue(':updated', time());
$Qupdate->execute();
return $this;
}
public function getTime(){
$Qselect = $this->db->prepare('SELECT updated FROM storage WHERE key = :key');
$Qselect->bindValue(':key', $this->getCacheKey());
$result = $Qselect->execute();
if ($result instanceof SQLite3Result) {
$data = $result->fetchArray(SQLITE3_ASSOC);
if (isset($data['updated'])) {
return $data['updated'];
}
}
return null;
}
public function purgeCache($seconds){
$Qdelete = $this->db->prepare('DELETE FROM storage WHERE updated < :expired');
$Qdelete->bindValue(':expired', time() - $seconds);
$Qdelete->execute();
}
/**
* Set scope
* @return self
*/
public function setScope($scope){
if(is_null($scope) || !is_string($scope)) {
throw new \Exception('The given scope is invalid!');
}
$this->scope = $scope;
return $this;
}
/**
* Set key
* @return self
*/
public function setKey($key){
if (!empty($key) && is_array($key)) {
$key = array_map('strtolower', $key);
}
$key = json_encode($key);
if (!is_string($key)) {
throw new \Exception('The given key is invalid!');
}
$this->key = $key;
return $this;
}
////////////////////////////////////////////////////////////////////////////
private function getCacheKey(){
if(is_null($this->key)) {
throw new \Exception('Call "setKey" first!');
}
return hash('sha1', $this->scope . $this->key, true);
}
}