egroupware_official/api/src/Cache.php
Ralf Becker 8bb4f56149 implement (increment|decrement)Cache to avoid race-conditions if multiple processes update a value
implemented in memcached and APCu backends, default implementation using get&set in base-class
2021-05-31 20:32:10 +02:00

901 lines
30 KiB
PHP

<?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) 2009-16 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @version $Id$
*/
namespace EGroupware\Api;
/**
* 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 deprecated 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 returned
* 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 infinite (this time is not supported for request level!)
*
* Data is stored under an application name and a location, like egw_session::appsession().
* In fact data stored at cache level Api\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).
*
* "Admin >> clear cache and register hooks" always only clears instance level cache of
* calling instance. It never clears tree level cache, which makes it important to set
* reasonable expiry times or think about an other means of clearing that particular item.
* (Not clearing of tree-level cache is important, as regenerating it is an expensive
* operation for a huge scale EGroupware hosting operation.)
*
* Apps needing to talk to multiple EGroupware instances (eg. EGroupware Managementserver)
* can use install_id of instance as $level parameter to (set|get|unset)Cache method.
*
* If a callback is used to calculate the data, in case it's not found in the cache, e.g.:
* $data = Api\Cache::getCache(Api\Cache::(TREE|INSTANCE), $app, $location, function($params)
* {
* // code to calculate / query $data
* return $data;
* }, $params, $expiration);
* then we lock the $app:$location by storing some specific data, so only one callback is used
* to calculate the data, and other processes sleep until the data is calculate to avoid races.
*/
class 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)
*
* Default is set (if not set here) after class definition to Cache\Apc or Cache\Files,
* depending on function 'apc_fetch' exists or not
*
* @var array
*/
static $default_provider; // = array('EGroupware\Api\Cache\Files');// array('EGroupware\Api\Cache\Memcache','localhost');
/**
* Maximum expiration time, if set unlimited expiration (=0) or bigger expiration times are replaced with that time
*
* @var int
*/
static $max_expiration;
/**
* Used to determine keys for tree- and instance-level caches
*
* @var string
*/
static $egw_server_root = EGW_SERVER_ROOT;
/**
* Add some data in the cache, only if the key does not yet exist
*
* @param string $level use Api\Cache::(TREE|INSTANCE)
* @param string $app application storing data
* @param string $location location name for data
* @param mixed $data
* @param int $expiration =0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise incl. key already existed
*/
public static function addCache($level,$app,$location,$data,$expiration=0)
{
//error_log(__METHOD__."('$level','$app','$location',".array2string($data).",$expiration)");
switch($level)
{
case self::SESSION:
case self::REQUEST:
throw new Exception\WrongParameter(__METHOD__."('$level', ...) unsupported level parameter!");
case self::INSTANCE:
case self::TREE:
default:
if (!($provider = self::get_provider($level)))
{
return false;
}
// limit expiration to configured maximum time
if (isset(self::$max_expiration) && (!$expiration || $expiration > self::$max_expiration))
{
$expiration = self::$max_expiration;
}
return $provider->add(self::keys($level,$app,$location),$data,$expiration);
}
throw new Exception\WrongParameter(__METHOD__."() unknown level '$level'!");
}
/**
* Set some data in the cache
*
* @param string $level use Cache::(TREE|INSTANCE|SESSION|REQUEST)
* @param string $app application storing data
* @param string $location location name for data
* @param mixed $data
* @param int $expiration =0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
public static function setCache($level,$app,$location,$data,$expiration=0)
{
//error_log(__METHOD__."('$level','$app','$location',".array2string($data).",$expiration)");
switch($level)
{
case self::SESSION:
case self::REQUEST:
return call_user_func(array(__CLASS__,'set'.$level),$app,$location,$data,$expiration);
case self::INSTANCE:
case self::TREE:
default:
if (!($provider = self::get_provider($level)))
{
return false;
}
// limit expiration to configured maximum time
if (isset(self::$max_expiration) && (!$expiration || $expiration > self::$max_expiration))
{
$expiration = self::$max_expiration;
}
return $provider->set(self::keys($level,$app,$location),$data,$expiration);
}
throw new Exception\WrongParameter(__METHOD__."() unknown level '$level'!");
}
/**
* Increment some value in the cache
*
* @param string $level use Cache::(TREE|INSTANCE), Cache::(SESSION|REQUEST) are NOT supported!
* @param string $app application storing data
* @param string $location location name for data
* @param int $offset =1 how much to increment by
* @param int $intial_value =0 value to set and return, if not in cache
* @param int $expiration =0
* @return false|int new value on success, false on error
*/
public static function incrementCache(string $level, string $app, string $location, int $offset=1, int $intial_value=0, int $expiration=0)
{
//error_log(__METHOD__."('$level', '$app', '$location', $offset, $inital_value, $expiration)");
switch($level)
{
case self::SESSION:
case self::REQUEST:
break;
case self::INSTANCE:
case self::TREE:
default:
if (!($provider = self::get_provider($level)))
{
return false;
}
// limit expiration to configured maximum time
if (isset(self::$max_expiration) && (!$expiration || $expiration > self::$max_expiration))
{
$expiration = self::$max_expiration;
}
return $provider->increment(self::keys($level, $app, $location), $offset, $intial_value, $expiration);
}
throw new Exception\WrongParameter(__METHOD__."() unsupported level '$level'!");
}
/**
* Decrements value in cache, but never below 0
*
* If new value would be below 0, 0 will be set as new value!
*
* @param string $level use Cache::(TREE|INSTANCE), Cache::(SESSION|REQUEST) are NOT supported!
* @param string $app application storing data
* @param string $location location name for data
* @param int $offset =1 how much to increment by
* @param int $intial_value =0 value to set and return, if not in cache
* @param int $expiration =0
* @return false|int new value on success, false on error
*/
public static function decrementCache(string $level, string $app, string $location, int $offset=1, int $intial_value=0, int $expiration=0)
{
//error_log(__METHOD__."('$level', '$app', '$location', $offset, $inital_value, $expiration)");
switch($level)
{
case self::SESSION:
case self::REQUEST:
break;
case self::INSTANCE:
case self::TREE:
default:
if (!($provider = self::get_provider($level)))
{
return false;
}
// limit expiration to configured maximum time
if (isset(self::$max_expiration) && (!$expiration || $expiration > self::$max_expiration))
{
$expiration = self::$max_expiration;
}
return $provider->decrement(self::keys($level, $app, $location), $offset, $intial_value, $expiration);
}
throw new Exception\WrongParameter(__METHOD__."() unsupported level '$level'!");
}
/**
* Content stored to signal one callback is already running and calculating the data, to not run it multiple times
*/
const CALLBACK_LOCK = '***LOCKED***';
/**
* Maximum time an item is locked, to recover from eg. a crash while the lock is set
*/
const CALLBACL_LOCK_TIMEOUT = 10; // 10s
/**
* Time other processes sleep to wait for one callback to calculate the data
*/
const CALLBACK_LOCK_USLEEP = 50000; // 50ms
/**
* Get some data from the cache
*
* @param string $level use Api\Cache::(TREE|INSTANCE|SESSION|REQUEST)
* @param string $app application storing data
* @param string|array $location location(s) name for data
* @param callback $callback =null callback to get/create the value, if it's not cache
* @param array $callback_params =array() 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) or
* if $location is an array: location => data pairs for existing location-data, non-existing is not returned
*/
public static function getCache($level,$app,$location,$callback=null,array $callback_params=array(),$expiration=0)
{
switch($level)
{
case self::SESSION:
case self::REQUEST:
foreach((array)$location as $l)
{
$data[$l] = call_user_func(array(__CLASS__,'get'.$level),$app,$l,$callback,$callback_params,$expiration);
}
return is_array($location) ? $data : $data[$l];
case self::INSTANCE:
case self::TREE:
default:
if (!($provider = self::get_provider($level)))
{
return null;
}
try {
if (is_array($location))
{
if (!is_null($callback))
{
throw new Exception\WrongParameter(__METHOD__."() you can NOT use multiple locations (\$location parameter is an array) together with a callback!");
}
if (is_a($provider, 'EGroupware\Api\Cache\ProviderMultiple'))
{
$data = $provider->mget($keys=self::keys($level,$app,$location));
}
else // default implementation calls get multiple times
{
$data = array();
foreach($location as $l)
{
$data[$l] = $provider->get($keys=self::keys($level,$app,$l));
if (!isset($data[$l])) unset($data[$l]);
}
}
}
else
{
// try reading cached data and, if not found AND a callback to do so given, calculate it
// only allow one process to do the (heavy) calculation by storing some lock-data
// other processes reading the lock-data sleep for a short time, before try reading it again
for($n=10+self::CALLBACL_LOCK_TIMEOUT*1000000/self::CALLBACK_LOCK_USLEEP; $n >= 0; $n--)
{
$data = $provider->get($keys=self::keys($level,$app,$location));
if ($data === self::CALLBACK_LOCK)
{
usleep(self::CALLBACK_LOCK_USLEEP);
}
elseif($data === null && isset($callback))
{
$provider->set($keys, self::CALLBACK_LOCK, self::CALLBACL_LOCK_TIMEOUT);
try {
$data = call_user_func_array($callback, $callback_params);
}
catch(\Throwable $e) {
// remove lock, before re-throwing the exception/error
$provider->delete($keys);
throw $e;
}
// limit expiration to configured maximum time
if (isset(self::$max_expiration) && (!$expiration || $expiration > self::$max_expiration))
{
$expiration = self::$max_expiration;
}
$provider->set($keys, $data, $expiration);
break;
}
else
{
break;
}
}
}
}
catch(Exception $e) {
unset($e);
$data = null;
}
return $data;
}
throw new Exception\WrongParameter(__METHOD__."() unknown level '$level'!");
}
/**
* Unset some data in the cache
*
* @param string $level use Api\Cache::(TREE|INSTANCE|SESSION|REQUEST)
* @param string $app application storing data
* @param string $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
public static function unsetCache($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:
default:
if (!($provider = self::get_provider($level, false)))
{
return false;
}
return $provider->delete(self::keys($level,$app,$location));
}
throw new Exception\WrongParameter(__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 $expiration =0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
public static function setTree($app,$location,$data,$expiration=0)
{
//error_log(__METHOD__."('$app','$location',".array2string($data).",$expiration)");
return self::setCache(self::TREE,$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 =array() array with parameters for the callback
* @param int $expiration =0 expiration time in seconds, default 0 = never
* @return mixed NULL if data not found in cache (and no callback specified)
*/
public static function getTree($app,$location,$callback=null,array $callback_params=array(),$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 $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
public static function unsetTree($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 $expiration =0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
public static function setInstance($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 =array() array with parameters for the callback
* @param int $expiration =0 expiration time in seconds, default 0 = never
* @return mixed NULL if data not found in cache (and no callback specified)
*/
public static function getInstance($app,$location,$callback=null,array $callback_params=array(),$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 $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
public static function unsetInstance($app,$location)
{
return self::unsetCache(self::INSTANCE,$app,$location);
}
/**
* Prefix for appname to store expiration time in session cache
*/
const SESSION_EXPIRATION_PREFIX = '*expiration*';
/**
* 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 $expiration =0 expiration time in seconds, default 0 = never
* @return boolean true if data could be stored, false otherwise
*/
public static function setSession($app,$location,$data,$expiration=0)
{
if (isset($_SESSION[Session::EGW_SESSION_ENCRYPTED]))
{
if (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
}
$_SESSION[Session::EGW_APPSESSION_VAR][$app][$location] = $data;
if ($expiration > 0)
{
$_SESSION[Session::EGW_APPSESSION_VAR][self::SESSION_EXPIRATION_PREFIX.$app][$location] = time()+$expiration;
}
return true;
}
/**
* Get some data from the cache for the whole source tree (all instances)
*
* Returns a reference to the var in the session!
*
* @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 =array() array with parameters for the callback
* @param int $expiration =0 expiration time in seconds, default 0 = never
* @return mixed NULL if data not found in cache (and no callback specified)
*/
public static function &getSession($app, $location, $callback=null, array $callback_params=array(), $expiration=0)
{
if (isset($_SESSION[Session::EGW_SESSION_ENCRYPTED]))
{
if (Session::ERROR_LOG_DEBUG) error_log(__METHOD__.' called after session was encrypted --> ignored!');
$ret = null; // can no longer store something in the session, eg. because commit_session() was called
return $ret;
}
// check if entry is expired and clean it up in that case
if (isset($_SESSION[Session::EGW_APPSESSION_VAR][self::SESSION_EXPIRATION_PREFIX.$app][$location]) &&
$_SESSION[Session::EGW_APPSESSION_VAR][self::SESSION_EXPIRATION_PREFIX.$app][$location] < time())
{
unset($_SESSION[Session::EGW_APPSESSION_VAR][$app][$location],
$_SESSION[Session::EGW_APPSESSION_VAR][self::SESSION_EXPIRATION_PREFIX.$app][$location]);
}
if (!isset($_SESSION[Session::EGW_APPSESSION_VAR][$app][$location]) && !is_null($callback))
{
$_SESSION[Session::EGW_APPSESSION_VAR][$app][$location] = call_user_func_array($callback,$callback_params);
}
return $_SESSION[Session::EGW_APPSESSION_VAR][$app][$location];
}
/**
* Unset some data in the cache for the whole source tree (all instances)
*
* @param string $app application storing data
* @param string $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
public static function unsetSession($app,$location)
{
if (isset($_SESSION[Session::EGW_SESSION_ENCRYPTED]))
{
if (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
}
// check if entry is expired and clean it up in that case
if (isset($_SESSION[Session::EGW_APPSESSION_VAR][self::SESSION_EXPIRATION_PREFIX.$app][$location]) &&
$_SESSION[Session::EGW_APPSESSION_VAR][self::SESSION_EXPIRATION_PREFIX.$app][$location] < time())
{
unset($_SESSION[Session::EGW_APPSESSION_VAR][$app][$location],
$_SESSION[Session::EGW_APPSESSION_VAR][self::SESSION_EXPIRATION_PREFIX.$app][$location]);
}
if (!isset($_SESSION[Session::EGW_APPSESSION_VAR][$app][$location]))
{
return false;
}
unset($_SESSION[Session::EGW_APPSESSION_VAR][$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 $expiration =0 expiration time is NOT used for REQUEST!
* @return boolean true if data could be stored, false otherwise
*/
public static function setRequest($app,$location,$data,$expiration=0)
{
unset($expiration); // not used, but required by function signature
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 =array() array with parameters for the callback
* @param int $expiration =0 expiration time is NOT used for REQUEST!
* @return mixed NULL if data not found in cache (and no callback specified)
*/
public static function getRequest($app,$location,$callback=null,array $callback_params=array(),$expiration=0)
{
unset($expiration); // not used, but required by function signature
if (!isset(self::$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 $location location name for data
* @return boolean true if data was set, false if not (like isset())
*/
public static function unsetRequest($app,$location)
{
if (!isset(self::$request_cache[$app][$location]))
{
return false;
}
unset(self::$request_cache[$app][$location]);
return true;
}
/**
* Get a caching provider for tree or instance level
*
* The returned provider already has an opened connection
*
* @param string $level Api\Cache::(TREE|INSTANCE) or install_id
* @param boolean $log_not_found =true false do not log if no provider found, used eg. to supress error via unsetCache during installation
* @return Cache\Provider|Cache\ProviderMultiple
*/
static protected function get_provider($level, $log_not_found=true)
{
static $providers = array();
if ($level != self::TREE) $level = self::INSTANCE;
if (!isset($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] && $log_not_found) error_log(__METHOD__."($level) no provider found ($reason)!".function_backtrace());
}
//error_log(__METHOD__."($level) = ".array2string($providers[$level]).', cache_provider='.array2string($GLOBALS['egw_info']['server']['cache_provider_'.strtolower($level)]));
return $providers[$level];
}
/**
* Get class-name of caching provider
*
* @param string $level
* @return string class-name of provider
*/
public static function getProvider($level=self::INSTANCE)
{
$provider = self::get_provider($level);
return get_class($provider);
}
/**
* Get a system configuration, even if in setup and it's not read
*
* @param string $name
* @param boolean $throw =true throw an exception, if we can't retriev the value
* @return string|boolean string with config or false if not found and !$throw
*/
public static function get_system_config($name, $throw=true)
{
if(!isset($GLOBALS['egw_info']['server'][$name]))
{
if (isset($GLOBALS['egw_setup']) && isset($GLOBALS['egw_setup']->db) || $GLOBALS['egw']->db)
{
$db = $GLOBALS['egw']->db ? $GLOBALS['egw']->db : $GLOBALS['egw_setup']->db;
try {
if (($rs = $db->select(Config::TABLE,'config_value',array(
'config_app' => 'phpgwapi',
'config_name' => $name,
),__LINE__,__FILE__)))
{
$GLOBALS['egw_info']['server'][$name] = $rs->fetchColumn();
}
else
{
error_log(__METHOD__."('$name', $throw) config value NOT found!");//.function_backtrace());
}
}
catch(Db\Exception $e)
{
if ($throw) error_log(__METHOD__."('$name', $throw) cound NOT query value: ".$e->getMessage());//.function_backtrace());
}
}
if (!$GLOBALS['egw_info']['server'][$name] && $throw)
{
throw new Exception (__METHOD__."($name) \$GLOBALS['egw_info']['server']['$name'] is NOT set!");
}
}
return $GLOBALS['egw_info']['server'][$name];
}
/**
* Flush (delete) whole (instance) cache or application/class specific part of it
*
* @param string $level =self::INSTANCE
* @param string $app =null app-name or "all" to empty complete cache
*/
public static function flush($level=self::INSTANCE, $app=null)
{
$ret = true;
if (!($provider = self::get_provider($level)))
{
$ret = false;
}
else
{
if (!$provider->flush($app !== "all" ? self::keys($level, $app) : array()))
{
if ($level == self::INSTANCE)
{
self::generate_instance_key();
}
else
{
$ret = false;
}
}
}
//error_log(__METHOD__."('$level', '$app') returning ".array2string($ret));
return $ret;
}
/**
* Unset instance key, so it get read again and re-read install_id from database
*/
public static function unset_instance_key()
{
self::$instance_key = null;
$GLOBALS['egw_info']['server']['install_id'] = self::get_system_config('install_id', false);
}
/**
* Key used for instance specific data
*
* @var string
*/
private static $instance_key;
/**
* Generate a new instance key and by doing so effectivly flushes whole instance cache
*
* @param string $install_id =null default use install_id of current instance
* @return string new key also stored in self::$instance_key
*/
public static function generate_instance_key($install_id=null)
{
if (!isset($install_id))
{
self::$instance_key = null;
$install_id = self::get_system_config('install_id');
}
$instance_key = self::INSTANCE.'-'.$install_id.'-'.microtime(true);
self::setTree(__CLASS__, $install_id, $instance_key);
//error_log(__METHOD__."(install_id='$install_id') returning '".$instance_key."'");
return $instance_key;
}
/**
* Get keys array from $level, $app and $location
*
* @param string $level Api\Cache::(TREE|INSTANCE) or instance_id
* @param string $app =null
* @param string $location =null
* @return array
*/
public static function keys($level, $app=null, $location=null)
{
static $tree_key = null;
switch($level)
{
case self::TREE:
if (!isset($tree_key))
{
$tree_key = $level.'-'.str_replace(array(':','/','\\'),'-', self::$egw_server_root);
// add charset to key, if not utf-8 (as everything we store depends on charset!)
if (($charset = self::get_system_config('system_charset',false)) && $charset != 'utf-8')
{
$tree_key .= '-'.$charset;
}
}
$level_key = $tree_key;
break;
default: // arbitrary install_id given --> check for current instance
if ($level !== $GLOBALS['egw_info']['server']['install_id'])
{
$level_key = self::getTree(__CLASS__, $level);
if (!isset($level_key)) $level_key = self::generate_instance_key($level);
break;
}
// fall-through for current instance
case self::INSTANCE:
if (!isset(self::$instance_key))
{
self::$instance_key = self::getTree(__CLASS__, self::get_system_config('install_id'));
//error_log(__METHOD__."('$level',...) instance_key read from tree-cache=".array2string(self::$instance_key));
if (!isset(self::$instance_key)) self::$instance_key = self::generate_instance_key();
}
$level_key = self::$instance_key;
break;
}
$keys = array($level_key);
if (isset($app))
{
$keys[] = $app;
if (isset($location)) $keys[] = $location;
}
return $keys;
}
/**
* Let everyone know the methods of this class should be used only statically
*
*/
function __construct()
{
throw new Exception\WrongParameter("All methods of class ".__CLASS__." should be called static!");
}
}
// setting apc(u) as default provider, if apc(u)_fetch function exists AND further checks in Api\Cache\Apc(u) recommed it
if (is_null(Cache::$default_provider))
{
Cache::$default_provider =
PHP_SAPI === 'cli' ? 'EGroupware\Api\Cache\Files' :
(function_exists('apcu_fetch') && Cache\Apcu::available() ? 'EGroupware\Api\Cache\Apcu' :
(function_exists('apc_fetch') && Cache\Apc::available() ? 'EGroupware\Api\Cache\Apc' :
'EGroupware\Api\Cache\Files'));
}
//error_log('Cache::$default_provider='.array2string(Cache::$default_provider));