TCache is the base class for cache classes with different cache storage implementation.
TCache implements the interface {@link ICache} with the following methods,
- {@link get} : retrieve the value with a key (if any) from cache
- {@link set} : store the value with a key into cache
- {@link add} : store the value only if cache does not have this key
- {@link delete} : delete the value with the specified key from cache
- {@link flush} : delete all values from cache
Each value is associated with an expiration time. The {@link get} operation
ensures that any expired value will not be returned. The expiration time by
the number of seconds. A expiration time 0 represents never expire.
By definition, cache does not ensure the existence of a value
even if it never expires. Cache is not meant to be an persistent storage.
Child classes must implement the following methods:
- {@link getValue}
- {@link setValue}
- {@link addValue}
- {@link deleteValue}
and optionally {@link flush}
Since version 3.1.2, TCache implements the \ArrayAccess interface such that
the cache acts as an array.
* @package Prado\Caching */ namespace Prado\Caching; use Prado\Exceptions\TConfigurationException; /** * TEACache class *
/**
* Initializes this module.
* This method is required by the IModule interface.
* @param TXmlElement configuration for this module, can be null
* @throws TConfigurationException if xcache extension is not installed or not started, check your php.ini
*/
public function init($config)
{
if (!function_exists('xcache_isset')) {
throw new TConfigurationException('xcache_extension_required');
}
$enabled = (int) ini_get('xcache.cacher') !== 0;
$var_size = (int) ini_get('xcache.var_size');
if (!($enabled && $var_size > 0)) {
throw new TConfigurationException('xcache_extension_not_enabled');
}
parent::init($config);
}
/**
* Initializes this module.
* This method is required by the IModule interface.
* @param TXmlElement configuration for this module, can be null
* @throws TConfigurationException if apc extension is not installed or not started, check your php.ini
*/
public function init($config)
{
if (!extension_loaded('apc')) {
throw new TConfigurationException('apccache_extension_required');
}
if (ini_get('apc.enabled') == false) {
throw new TConfigurationException('apccache_extension_not_enabled');
}
if (substr(php_sapi_name(), 0, 3) === 'cli' and ini_get('apc.enable_cli') == false) {
throw new TConfigurationException('apccache_extension_not_enabled_cli');
}
parent::init($config);
}
/**
* Initializes this module.
* This method is required by the IModule interface.
* attach {@link doInitializeCache} to TApplication.OnLoadStateComplete event
* attach {@link doFlushCacheExpired} to TApplication.OnSaveState event
*
* @param TXmlElement configuration for this module, can be null
*/
public function init($config)
{
$this->getApplication()->attachEventHandler('OnLoadStateComplete', array($this, 'doInitializeCache'));
$this->getApplication()->attachEventHandler('OnSaveState', array($this, 'doFlushCacheExpired'));
parent::init($config);
}
/**
* Initializes this module.
* This method is required by the IModule interface. It checks if the DbFile
* property is set, and creates a SQLiteDatabase instance for it.
* The database or the cache table does not exist, they will be created.
* Expired values are also deleted.
* @param TXmlElement configuration for this module, can be null
* @throws TConfigurationException if sqlite extension is not installed,
* DbFile is set invalid, or any error happens during creating database or cache table.
*/
public function init($config)
{
if (!function_exists('sqlite_open')) {
throw new TConfigurationException('sqlitecache_extension_required');
}
if ($this->_file === null) {
$this->_file = $this->getApplication()->getRuntimePath() . '/sqlite.cache';
}
$error = '';
if (($this->_db = new \SQLiteDatabase($this->_file, 0666, $error)) === false) {
throw new TConfigurationException('sqlitecache_connection_failed', $error);
}
if (@$this->_db->query('DELETE FROM ' . self::CACHE_TABLE . ' WHERE expire<>0 AND expire<' . time()) === false) {
if ($this->_db->query('CREATE TABLE ' . self::CACHE_TABLE . ' (key CHAR(128) PRIMARY KEY, value BLOB, expire INT)') === false) {
throw new TConfigurationException('sqlitecache_table_creation_failed', sqlite_error_string(sqlite_last_error()));
}
}
$this->_initialized = true;
parent::init($config);
}
/**
* Initializes this module.
* This method is required by the IModule interface. It makes sure that
* UniquePrefix has been set, creates a Memcache instance and connects
* to the memcache server.
* @param TApplication Prado application, can be null
* @param TXmlElement configuration for this module, can be null
* @throws TConfigurationException if memcache extension is not installed or memcache sever connection fails
*/
public function init($config)
{
if (!extension_loaded('memcache') && !$this->_useMemcached) {
throw new TConfigurationException('memcache_extension_required');
}
if (!extension_loaded('memcached') && $this->_useMemcached) {
throw new TConfigurationException('memcached_extension_required');
}
$this->_cache = $this->_useMemcached ? new Memcached() : new Memcache();
$this->loadConfig($config);
if (count($this->_servers)) {
foreach ($this->_servers as $server) {
Prado::trace('Adding server ' . $server['Host'] . ' from serverlist', '\\Prado\\Caching\\TMemCache');
if ($this->_cache->addServer($server['Host'], $server['Port'], $server['Persistent'], $server['Weight'], $server['Timeout'], $server['RetryInterval']) === false) {
throw new TConfigurationException('memcache_connection_failed', $server['Host'], $server['Port']);
}
}
} else {
Prado::trace('Adding server ' . $this->_host, '\\Prado\\Caching\\TMemCache');
if ($this->_cache->addServer($this->_host, $this->_port) === false) {
throw new TConfigurationException('memcache_connection_failed', $this->_host, $this->_port);
}
}
if ($this->_threshold !== 0) {
$this->_cache->setCompressThreshold($this->_threshold, $this->_minSavings);
}
$this->_initialized = true;
parent::init($config);
}