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<?php
/**
* Caching for CakePHP.
*
*
* PHP 5
*
* CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
* Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
*
* Licensed under The MIT License
* Redistributions of files must retain the above copyright notice.
*
* @copyright Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
* @link http://cakephp.org CakePHP(tm) Project
* @package cake.libs
* @since CakePHP(tm) v 1.2.0.4933
* @license MIT License (http://www.opensource.org/licenses/mit-license.php)
*/
App::uses('Inflector', 'Utility');
/**
* Cache provides a consistent interface to Caching in your application. It allows you
* to use several different Cache engines, without coupling your application to a specific
* implementation. It also allows you to change out cache storage or configuration without effecting
* the rest of your application.
*
* You can configure Cache engines in your application's `bootstrap.php` file. A sample configuration would
* be
*
* {{{
* Cache::config('shared', array(
* 'engine' => 'Apc',
* 'prefix' => 'my_app_'
* ));
* }}}
*
* This would configure an APC cache engine to the 'shared' alias. You could then read and write
* to that cache alias by using it for the `$config` parameter in the various Cache methods. In
* general all Cache operations are supported by all cache engines. However, Cache::increment() and
* Cache::decrement() are not supported by File caching.
*
* @package cake.libs
*/
class Cache {
/**
* Cache configuration stack
* Keeps the permanent/default settings for each cache engine.
* These settings are used to reset the engines after temporary modification.
*
* @var array
*/
protected static $_config = array();
/**
* Whether to reset the settings with the next call to Cache::set();
*
* @var array
*/
protected static $_reset = false;
/**
* Engine instances keyed by configuration name.
*
* @var array
*/
protected static $_engines = array();
/**
* Set the cache configuration to use. config() can
* both create new configurations, return the settings for already configured
* configurations.
*
* To create a new configuration, or to modify an existing configuration permanently:
*
* `Cache::config('my_config', array('engine' => 'File', 'path' => TMP));`
*
* If you need to modify a configuration temporarily, use Cache::set().
* To get the settings for a configuration:
*
* `Cache::config('default');`
*
* There are 4 built-in caching engines:
*
* - `FileEngine` - Uses simple files to store content. Poor performance, but good for
* storing large objects, or things that are not IO sensitive.
* - `ApcEngine` - Uses the APC object cache, one of the fastest caching engines.
* - `MemcacheEngine` - Uses the PECL::Memcache extension and Memcached for storage.
* Fast reads/writes, and benefits from memcache being distributed.
* - `XcacheEngine` - Uses the Xcache extension, an alternative to APC.
*
* The following keys are used in core cache engines:
*
* - `duration` Specify how long items in this cache configuration last.
* - `prefix` Prefix appended to all entries. Good for when you need to share a keyspace
* with either another cache config or annother application.
* - `probability` Probability of hitting a cache gc cleanup. Setting to 0 will disable
* cache::gc from ever being called automatically.
* - `servers' Used by memcache. Give the address of the memcached servers to use.
* - `compress` Used by memcache. Enables memcache's compressed format.
* - `serialize` Used by FileCache. Should cache objects be serialized first.
* - `path` Used by FileCache. Path to where cachefiles should be saved.
* - `lock` Used by FileCache. Should files be locked before writing to them?
* - `user` Used by Xcache. Username for XCache
* - `password` Used by Xcache. Password for XCache
*
* @see app/Config/core.php for configuration settings
* @param string $name Name of the configuration
* @param array $settings Optional associative array of settings passed to the engine
* @return array(engine, settings) on success, false on failure
* @throws CacheException
*/
public static function config($name = null, $settings = array()) {
if (is_array($name)) {
$settings = $name;
}
$current = array();
if (isset(self::$_config[$name])) {
$current = self::$_config[$name];
}
if (!empty($settings)) {
self::$_config[$name] = array_merge($current, $settings);
}
if (empty(self::$_config[$name]['engine'])) {
return false;
}
$engine = self::$_config[$name]['engine'];
if (!isset(self::$_engines[$name])) {
self::_buildEngine($name);
$settings = self::$_config[$name] = self::settings($name);
} elseif ($settings = self::set(self::$_config[$name], null, $name)) {
self::$_config[$name] = $settings;
}
return compact('engine', 'settings');
}
/**
* Finds and builds the instance of the required engine class.
*
* @param string $name Name of the config array that needs an engine instance built
* @return void
*/
protected static function _buildEngine($name) {
$config = self::$_config[$name];
list($plugin, $class) = pluginSplit($config['engine'], true);
$cacheClass = $class . 'Engine';
App::uses($cacheClass, $plugin . 'Cache/Engine');
if (!class_exists($cacheClass)) {
return false;
}
$cacheClass = $class . 'Engine';
if (!is_subclass_of($cacheClass, 'CacheEngine')) {
throw new CacheException(__d('cake_dev', 'Cache engines must use CacheEngine as a base class.'));
}
self::$_engines[$name] = new $cacheClass();
if (self::$_engines[$name]->init($config)) {
if (self::$_engines[$name]->settings['probability'] && time() % self::$_engines[$name]->settings['probability'] === 0) {
self::$_engines[$name]->gc();
}
return true;
}
return false;
}
/**
* Returns an array containing the currently configured Cache settings.
*
* @return array Array of configured Cache config names.
*/
public static function configured() {
return array_keys(self::$_config);
}
/**
* Drops a cache engine. Deletes the cache configuration information
* If the deleted configuration is the last configuration using an certain engine,
* the Engine instance is also unset.
*
* @param string $name A currently configured cache config you wish to remove.
* @return boolen success of the removal, returns false when the config does not exist.
*/
public static function drop($name) {
if (!isset(self::$_config[$name])) {
return false;
}
unset(self::$_config[$name], self::$_engines[$name]);
return true;
}
/**
* Temporarily change the settings on a cache config. The settings will persist for the next write
* operation (write, decrement, increment, clear). Any reads that are done before the write, will
* use the modified settings. If `$settings` is empty, the settings will be reset to the
* original configuration.
*
* Can be called with 2 or 3 parameters. To set multiple values at once.
*
* `Cache::set(array('duration' => '+30 minutes'), 'my_config');`
*
* Or to set one value.
*
* `Cache::set('duration', '+30 minutes', 'my_config');`
*
* To reset a config back to the originally configured values.
*
* `Cache::set(null, 'my_config');`
*
* @param mixed $settings Optional string for simple name-value pair or array
* @param string $value Optional for a simple name-value pair
* @param string $config The configuration name you are changing. Defaults to 'default'
* @return array Array of settings.
*/
public static function set($settings = array(), $value = null, $config = 'default') {
if (is_array($settings) && $value !== null) {
$config = $value;
}
if (!isset(self::$_config[$config]) || !isset(self::$_engines[$config])) {
return false;
}
if (!empty($settings)) {
self::$_reset = true;
}
if (self::$_reset === true) {
if (empty($settings)) {
self::$_reset = false;
$settings = self::$_config[$config];
} else {
if (is_string($settings) && $value !== null) {
$settings = array($settings => $value);
}
$settings = array_merge(self::$_config[$config], $settings);
if (isset($settings['duration']) && !is_numeric($settings['duration'])) {
$settings['duration'] = strtotime($settings['duration']) - time();
}
}
self::$_engines[$config]->settings = $settings;
}
return self::settings($config);
}
/**
* Garbage collection
*
* Permanently remove all expired and deleted data
*
* @param string $config The config name you wish to have garbage collected. Defaults to 'default'
* @return void
*/
public static function gc($config = 'default') {
self::$_engines[$config]->gc();
}
/**
* Write data for key into cache. Will automatically use the currently
* active cache configuration. To set the currently active configuration use
* Cache::config()
*
* ### Usage:
*
* Writing to the active cache config:
*
* `Cache::write('cached_data', $data);`
*
* Writing to a specific cache config:
*
* `Cache::write('cached_data', $data, 'long_term');`
*
* @param string $key Identifier for the data
* @param mixed $value Data to be cached - anything except a resource
* @param string $config Optional string configuration name to write to. Defaults to 'default'
* @return boolean True if the data was successfully cached, false on failure
*/
public static function write($key, $value, $config = 'default') {
$settings = self::settings($config);
if (empty($settings)) {
return null;
}
if (!self::isInitialized($config)) {
return false;
}
$key = self::$_engines[$config]->key($key);
if (!$key || is_resource($value)) {
return false;
}
$success = self::$_engines[$config]->write($settings['prefix'] . $key, $value, $settings['duration']);
self::set(null, $config);
if ($success === false && $value !== '') {
trigger_error(
__d('cake_dev',
"%s cache was unable to write '%s' to %s cache",
$config,
$key,
self::$_engines[$config]->settings['engine']
),
E_USER_WARNING
);
}
return $success;
}
/**
* Read a key from the cache. Will automatically use the currently
* active cache configuration. To set the currently active configuration use
* Cache::config()
*
* ### Usage:
*
* Reading from the active cache configuration.
*
* `Cache::read('my_data');`
*
* Reading from a specific cache configuration.
*
* `Cache::read('my_data', 'long_term');`
*
* @param string $key Identifier for the data
* @param string $config optional name of the configuration to use. Defaults to 'default'
* @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it
*/
public static function read($key, $config = 'default') {
$settings = self::settings($config);
if (empty($settings)) {
return null;
}
if (!self::isInitialized($config)) {
return false;
}
$key = self::$_engines[$config]->key($key);
if (!$key) {
return false;
}
return self::$_engines[$config]->read($settings['prefix'] . $key);
}
/**
* Increment a number under the key and return incremented value.
*
* @param string $key Identifier for the data
* @param integer $offset How much to add
* @param string $config Optional string configuration name. Defaults to 'default'
* @return mixed new value, or false if the data doesn't exist, is not integer,
* or if there was an error fetching it.
*/
public static function increment($key, $offset = 1, $config = 'default') {
$settings = self::settings($config);
if (empty($settings)) {
return null;
}
if (!self::isInitialized($config)) {
return false;
}
$key = self::$_engines[$config]->key($key);
if (!$key || !is_integer($offset) || $offset < 0) {
return false;
}
$success = self::$_engines[$config]->increment($settings['prefix'] . $key, $offset);
self::set(null, $config);
return $success;
}
/**
* Decrement a number under the key and return decremented value.
*
* @param string $key Identifier for the data
* @param integer $offset How much to subtract
* @param string $config Optional string configuration name. Defaults to 'default'
* @return mixed new value, or false if the data doesn't exist, is not integer,
* or if there was an error fetching it
*/
public static function decrement($key, $offset = 1, $config = 'default') {
$settings = self::settings($config);
if (empty($settings)) {
return null;
}
if (!self::isInitialized($config)) {
return false;
}
$key = self::$_engines[$config]->key($key);
if (!$key || !is_integer($offset) || $offset < 0) {
return false;
}
$success = self::$_engines[$config]->decrement($settings['prefix'] . $key, $offset);
self::set(null, $config);
return $success;
}
/**
* Delete a key from the cache.
*
* ### Usage:
*
* Deleting from the active cache configuration.
*
* `Cache::delete('my_data');`
*
* Deleting from a specific cache configuration.
*
* `Cache::delete('my_data', 'long_term');`
*
* @param string $key Identifier for the data
* @param string $config name of the configuration to use. Defaults to 'default'
* @return boolean True if the value was successfully deleted, false if it didn't exist or couldn't be removed
*/
public static function delete($key, $config = 'default') {
$settings = self::settings($config);
if (empty($settings)) {
return null;
}
if (!self::isInitialized($config)) {
return false;
}
$key = self::$_engines[$config]->key($key);
if (!$key) {
return false;
}
$success = self::$_engines[$config]->delete($settings['prefix'] . $key);
self::set(null, $config);
return $success;
}
/**
* Delete all keys from the cache.
*
* @param boolean $check if true will check expiration, otherwise delete all
* @param string $config name of the configuration to use. Defaults to 'default'
* @return boolean True if the cache was successfully cleared, false otherwise
*/
public static function clear($check = false, $config = 'default') {
if (!self::isInitialized($config)) {
return false;
}
$success = self::$_engines[$config]->clear($check);
self::set(null, $config);
return $success;
}
/**
* Check if Cache has initialized a working config for the given name.
*
* @param string $config name of the configuration to use. Defaults to 'default'
* @return bool Whether or not the config name has been initialized.
*/
public static function isInitialized($config = 'default') {
if (Configure::read('Cache.disable')) {
return false;
}
return isset(self::$_engines[$config]);
}
/**
* Return the settings for the named cache engine.
*
* @param string $name Name of the configuration to get settings for. Defaults to 'default'
* @return array list of settings for this engine
* @see Cache::config()
* @access public
* @static
*/
public static function settings($name = 'default') {
if (!empty(self::$_engines[$name])) {
return self::$_engines[$name]->settings();
}
return array();
}
}
/**
* Storage engine for CakePHP caching
*
* @package cake.libs
*/
abstract class CacheEngine {
/**
* Settings of current engine instance
*
* @var int
* @access public
*/
public $settings = array();
/**
* Initialize the cache engine
*
* Called automatically by the cache frontend
*
* @param array $settings Associative array of parameters for the engine
* @return boolean True if the engine has been successfully initialized, false if not
*/
public function init($settings = array()) {
$this->settings = array_merge(
array('prefix' => 'cake_', 'duration'=> 3600, 'probability'=> 100),
$this->settings,
$settings
);
if (!is_numeric($this->settings['duration'])) {
$this->settings['duration'] = strtotime($this->settings['duration']) - time();
}
return true;
}
/**
* Garbage collection
*
* Permanently remove all expired and deleted data
* @return void
*/
public function gc() { }
/**
* Write value for a key into cache
*
* @param string $key Identifier for the data
* @param mixed $value Data to be cached
* @param mixed $duration How long to cache for.
* @return boolean True if the data was successfully cached, false on failure
*/
abstract public function write($key, $value, $duration);
/**
* Read a key from the cache
*
* @param string $key Identifier for the data
* @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it
*/
abstract public function read($key);
/**
* Increment a number under the key and return incremented value
*
* @param string $key Identifier for the data
* @param integer $offset How much to add
* @return New incremented value, false otherwise
*/
abstract public function increment($key, $offset = 1);
/**
* Decrement a number under the key and return decremented value
*
* @param string $key Identifier for the data
* @param integer $offset How much to subtract
* @return New incremented value, false otherwise
*/
abstract public function decrement($key, $offset = 1);
/**
* Delete a key from the cache
*
* @param string $key Identifier for the data
* @return boolean True if the value was successfully deleted, false if it didn't exist or couldn't be removed
*/
abstract public function delete($key);
/**
* Delete all keys from the cache
*
* @param boolean $check if true will check expiration, otherwise delete all
* @return boolean True if the cache was successfully cleared, false otherwise
*/
abstract public function clear($check);
/**
* Cache Engine settings
*
* @return array settings
*/
public function settings() {
return $this->settings;
}
/**
* Generates a safe key for use with cache engine storage engines.
*
* @param string $key the key passed over
* @return mixed string $key or false
*/
public function key($key) {
if (empty($key)) {
return false;
}
$key = Inflector::underscore(str_replace(array(DS, '/', '.'), '_', strval($key)));
return $key;
}
}
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