egroupware/phpgwapi/inc/class.egw_cache.inc.php

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Class to manage caching in eGroupware: It allows to cache on 4 levels: a) tree: for all instances/domains runining on a certain source path b) instance: for all sessions on a given instance c) session: for all requests of a session, same as egw_session::appsession() d) request: just for this request (same as using a static variable) There's a get, a set and a unset method for each level: eg. getTree() or setInstance(), as well as a variant allowing to specify the level as first parameter: eg. unsetCache() getXXX($app,$location,$callback=null,array $callback_params,$expiration=0) has three optional parameters allowing to specify: 3. a callback if requested data is not yes stored. In that case the callback is called and it's value is stored in the cache AND retured 4. parameters to pass to the callback as array, see call_user_func_array 5. an expiration time in seconds to specify how long data should be cached, default 0 means infinit (this time is not garantied and not supported for all levels!) Data is stored under an application name and a location, like egw_session::appsession(). In fact data stored at cache level egw_cache::SESSION, is stored in the same way as egw_session::appsession() so both methods can be used with each other. The $app parameter should be either the app or the class name, which both are unique. The tree and instance wide cache uses a certain provider class, to store the data eg. in memcached or if there's nothing else configured in the filesystem (eGW's temp_dir).
2009-04-20 13:50:45 +02:00
<?php
/**
* eGroupWare API: Caching data
*
* @link http://www.egroupware.org
* @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
* @package api
* @subpackage cache
* @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @copyright (c) 2009 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @version $Id$
*/
/**
* Class to manage caching in eGroupware.
*
* It allows to cache on 4 levels:
* a) tree: for all instances/domains runining on a certain source path
* b) instance: for all sessions on a given instance
* c) session: for all requests of a session, same as egw_session::appsession()
* d) request: just for this request (same as using a static variable)
*
* There's a get, a set and a unset method for each level: eg. getTree() or setInstance(),
* as well as a variant allowing to specify the level as first parameter: eg. unsetCache()
*
* getXXX($app,$location,$callback=null,array $callback_params,$expiration=0)
* has three optional parameters allowing to specify:
* 3. a callback if requested data is not yes stored. In that case the callback is called
* and it's value is stored in the cache AND retured
* 4. parameters to pass to the callback as array, see call_user_func_array
* 5. an expiration time in seconds to specify how long data should be cached,
* default 0 means infinit (this time is not garantied and not supported for all levels!)
*
* Data is stored under an application name and a location, like egw_session::appsession().
* In fact data stored at cache level egw_cache::SESSION, is stored in the same way as
* egw_session::appsession() so both methods can be used with each other.
*
* The $app parameter should be either the app or the class name, which both are unique.
*
* The tree and instance wide cache uses a certain provider class, to store the data
* eg. in memcached or if there's nothing else configured in the session.
*/
class egw_cache
{
/**
* tree-wide storage
*/
const TREE = 'Tree';
/**
* instance-wide storage
*/
const INSTANCE = 'Instance';
/**
* session-wide storage
*/
const SESSION = 'Session';
/**
* request-wide storage
*/
const REQUEST = 'Request';
/**
* Default provider for tree and instance data
*
* Can be specified eg. in the header.inc.php by setting:
* $GLOBALS['egw_info']['server']['cache_provider_instance'] and optional
* $GLOBALS['egw_info']['server']['cache_provider_tree'] (defaults to instance)
*
* @var array
*/
static $default_provider = array('egw_cache_files');// array('egw_cache_memcache','localhost',11211);
/**
* Set some data in the cache
*
* @param string $level use egw_cache::(TREE|INSTANCE|SESSION|REQUEST)
* @param string $app application storing data
* @param string $location location name for data
* @param mixed $data
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
static public function setCache($level,$app,$location,$data,$expiration=0)
{
switch($level)
{
case self::SESSION:
case self::REQUEST:
return call_user_func(array(__CLASS__,'set'.$level),$app,$location,$data,$expiration);
case self::INSTANCE:
case self::TREE:
if (!($provider = self::get_provider($level)))
{
return false;
}
return $provider->set(self::keys($level,$app,$location),$data);
}
throw new egw_exception_wrong_parameter(__METHOD__."() unknown level '$level'!");
}
/**
* Get some data from the cache
*
* @param string $level use egw_cache::(TREE|INSTANCE|SESSION|REQUEST)
* @param string $app application storing data
* @param string $location location name for data
* @param callback $callback=null callback to get/create the value, if it's not cache
* @param array $callback_params=null array with parameters for the callback
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return mixed NULL if data not found in cache (and no callback specified)
*/
static public function getCache($level,$app,$location,$callback=null,array $callback_params=null,$expiration=0)
{
switch($level)
{
case self::SESSION:
case self::REQUEST:
return call_user_func(array(__CLASS__,'get'.$level),$app,$location,$callback,$callback_params,$expiration);
case self::INSTANCE:
case self::TREE:
if (!($provider = self::get_provider($level)))
{
return null;
}
$data = $provider->get($keys=self::keys($level,$app,$location));
if (is_null($data))
{
//error_log(__METHOD__."($level,$app,$location,".array2string($callback).','.array2string($callback_params).",$expiration) calling calback to create data.");
$data = call_user_func_array($callback,$callback_params);
$provider->set($keys,$data);
}
return $data;
}
throw new egw_exception_wrong_parameter(__METHOD__."() unknown level '$level'!");
}
/**
* Unset some data in the cache
*
* @param string $level use egw_cache::(TREE|INSTANCE|SESSION|REQUEST)
* @param string $app application storing data
* @param string $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
static public function unsetCache($level,$app,$location)
{
switch($level)
{
case self::SESSION:
case self::REQUEST:
return call_user_func(array(__CLASS__,'unset'.$level),$app,$location);
case self::INSTANCE:
case self::TREE:
if (!($provider = self::get_provider($level)))
{
return false;
}
return $provider->delete(self::keys($level,$app,$location));
}
throw new egw_exception_wrong_parameter(__METHOD__."() unknown level '$level'!");
}
/**
* Set some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param mixed $data
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
static public function setTree($app,$location,$data,$expiration=0)
{
return self::setCache(self::TREE,$app,$location,$data,$expiration);
}
/**
* Get some data from the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param callback $callback=null callback to get/create the value, if it's not cache
* @param array $callback_params=null array with parameters for the callback
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return mixed NULL if data not found in cache (and no callback specified)
*/
static public function getTree($app,$location,$callback=null,array $callback_params=null,$expiration=0)
{
return self::getCache(self::TREE,$app,$location,$callback,$callback_params,$expiration);
}
/**
* Unset some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
static public function unsetTree($app,$location)
{
return self::unsetCache(self::TREE,$app,$location);
}
/**
* Set some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param mixed $data
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
static public function setInstance($app,$location,$data,$expiration=0)
{
return self::setCache(self::INSTANCE,$app,$location,$data,$expiration);
}
/**
* Get some data from the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param callback $callback=null callback to get/create the value, if it's not cache
* @param array $callback_params=null array with parameters for the callback
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return mixed NULL if data not found in cache (and no callback specified)
*/
static public function getInstance($app,$location,$callback=null,array $callback_params=null,$expiration=0)
{
return self::getCache(self::INSTANCE,$app,$location,$callback,$callback_params,$expiration);
}
/**
* Unset some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
static public function unsetInstance($app,$location)
{
return self::getCache(self::INSTANCE,$app,$location);
}
/**
* Set some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param mixed $data
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
static public function setSession($app,$location,$data,$expiration=0)
{
if (isset($_SESSION[egw_session::EGW_SESSION_ENCRYPTED]))
{
if (egw_session::ERROR_LOG_DEBUG) error_log(__METHOD__.' called after session was encrypted --> ignored!');
return false; // can no longer store something in the session, eg. because commit_session() was called
}
$_SESSION[egw_session::EGW_APPSESSION_VAR][$app][$location] = $data;
return true;
}
/**
* Get some data from the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param callback $callback=null callback to get/create the value, if it's not cache
* @param array $callback_params=null array with parameters for the callback
* @param int $expiration=0 expiration time in seconds, default 0 = never
* @return mixed NULL if data not found in cache (and no callback specified)
*/
static public function getSession($app,$location,$callback=null,array $callback_params=null,$expiration=0)
{
if (isset($_SESSION[egw_session::EGW_SESSION_ENCRYPTED]))
{
if (egw_session::ERROR_LOG_DEBUG) error_log(__METHOD__.' called after session was encrypted --> ignored!');
return null; // can no longer store something in the session, eg. because commit_session() was called
}
if (!isset($_SESSION[egw_session::EGW_APPSESSION_VAR][$app][$location]) && !is_null($callback))
{
$_SESSION[egw_session::EGW_APPSESSION_VAR][$app][$location] = call_user_func_array($callback,$callback_params);
}
return $_SESSION[egw_session::EGW_APPSESSION_VAR][$app][$location];
}
/**
* Unset some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
static public function unsetSession($app,$location)
{
if (isset($_SESSION[egw_session::EGW_SESSION_ENCRYPTED]))
{
if (egw_session::ERROR_LOG_DEBUG) error_log(__METHOD__.' called after session was encrypted --> ignored!');
return false; // can no longer store something in the session, eg. because commit_session() was called
}
if (!isset($_SESSION[egw_session::EGW_APPSESSION_VAR][$app][$location]))
{
return false;
}
unset($_SESSION[egw_session::EGW_APPSESSION_VAR][$app][$location]);
return true;
}
/**
* Static varible to cache request wide
*
* @var array
*/
private static $request_cache = array();
/**
* Set some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param mixed $data
* @param int $expiration=0 expiration time is NOT used for REQUEST!
* @return boolean true if data could be stored, false otherwise
*/
static public function setRequest($app,$location,$data,$expiration=0)
{
self::$request_cache[$app][$location] = $data;
return true;
}
/**
* Get some data from the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @param callback $callback=null callback to get/create the value, if it's not cache
* @param array $callback_params=null array with parameters for the callback
* @param int $expiration=0 expiration time is NOT used for REQUEST!
* @return mixed NULL if data not found in cache (and no callback specified)
*/
static public function getRequest($app,$location,$callback=null,array $callback_params=null,$expiration=0)
{
if (!isset(self::$request_cache[$app][$location]) && !is_null($callback))
{
self::$request_cache[$app][$location] = call_user_func_array($callback,$callback_params);
}
return self::$request_cache[$app][$location];
}
/**
* Unset some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
static public function unsetRequest($app,$location)
{
if (!isset(self::$request_cache[$app][$location]))
{
return false;
}
unset(self::$request_cache[$app][$location]);
return $ret;
}
/**
* Get a caching provider for tree or instance level
*
* The returned provider already has an opened connection
*
* @param string $level egw_cache::(TREE|INSTANCE)
* @return egw_cache_provider
*/
static protected function get_provider($level)
{
static $providers = array();
if (!isset($providers[$level]))
{
$params = $GLOBALS['egw_info']['server']['cache_provider_'.strtolower($level)];
if (!isset($params) && $level == self::INSTANCE && isset(self::$default_provider))
{
$params = self::$default_provider;
}
if (!isset($params))
{
if ($level == self::TREE) // if no tree level provider use the instance level one
{
$providers[$level] = self::get_provider(self::INSTANCE);
}
else
{
$providers[$level] = false; // no provider specified
$reason = 'no provider specified';
}
}
elseif (!$params)
{
$providers[$level] = false; // cache for $level disabled
$reason = "cache for $level disabled";
}
else
{
if (!is_array($params)) $params = (array)$params;
$class = array_shift($params);
if (!class_exists($class))
{
$providers[$level] = false; // provider class not found
$reason = "provider $class not found";
}
else
{
try
{
$providers[$level] = new $class($params);
}
catch(Exception $e)
{
$providers[$level] = false; // eg. could not open connection to backend
$reason = "error instanciating provider $class: ".$e->getMessage();
}
}
}
if (!$providers[$level]) error_log(__METHOD__."($level) no provider found ($reason)!");
}
return $providers[$level];
}
/**
* Get keys array from $level, $app and $location
*
* @param string $level egw_cache::(TREE|INSTANCE)
* @param string $app
* @param string $location
* @return array
*/
static protected function keys($level,$app,$location)
{
static $bases = array();
if (!isset($bases[$level]))
{
switch($level)
{
case self::TREE:
$bases[$level] = $level.'-'.str_replace(array(':','/','\\'),'-',EGW_SERVER_ROOT);
break;
case self::INSTANCE:
$bases[$level] = $level.'-'.$GLOBALS['egw_info']['server']['install_id'];
break;
}
}
return array($bases[$level],$app,$location);
}
/**
* Let everyone know the methods of this class should be used only statically
*
*/
function __construct()
{
throw new egw_exception_wrong_parameter("All methods of class ".__CLASS__." should be called static!");
}
}
/**
* Interface for a caching provider for tree and instance level
*
* The provider can eg. create subdirs under /tmp for each key
* to store data as a file or concat them with a separator to
* get a single string key to eg. store data in memcached
*/
interface egw_cache_provider
{
/**
* Constructor, eg. opens the connection to the backend
*
* @throws Exception if connection to backend could not be established
* @param array $params eg. array(host,port) or array(directory) depending on the provider
*/
function __construct(array $params);
/**
* Stores some data in the cache
*
* @param array $keys eg. array($level,$app,$location)
* @param mixed $data
* @param int $expiration=0
* @return boolean true on success, false on error
*/
function set(array $keys,$data,$expiration=0);
/**
* Get some data from the cache
*
* @param array $keys eg. array($level,$app,$location)
* @return mixed data stored or NULL if not found in cache
*/
function get(array $keys);
/**
* Delete some data from the cache
*
* @param array $keys eg. array($level,$app,$location)
* @return boolean true on success, false on error (eg. $key not set)
*/
function delete(array $keys);
}