/**
* Sets an fCache object to store sessions in
*
* While any type of fCache backend should technically work, it would be
* unwise to use the `file` and `directory` types. The `file` caching
* backend stores all values in a single file, which would quickly become a
* performance bottleneck and could cause data loss with many concurrent
* users. The `directory` caching backend would not make sense since it is
* the same general functionality as the default session handler, but it
* would be slightly slower since it is written in PHP and not C.
*
* It is recommended to set the `serializer` and `unserializer` `$config`
* settings on the fCache object to `string` for the best performance and
* minimal storage space.
*
* For better performance, check out using the built-in session handlers
* that are bundled with the following extensions:
*
* - [http://php.net/memcached.sessions memcached]
* - [http://php.net/memcache.examples-overview#example-3596 memcache]
* - [https://github.com/nicolasff/phpredis redis]
*
* The [http://pecl.php.net/package/igbinary igbinary] extension can
* provide even more of a performance boost by storing serialized data in
* binary format instead of as text.
*
* @param fCache $backend An fCache object to store session values in
* @param string $key_prefix A prefix to add to all session IDs before storing them in the cache
* @return void
*/
public static function setBackend($backend, $key_prefix = '')
{
if (self::$open || isset($_SESSION)) {
throw new fProgrammerException('%1$s must be called before any of %2$s, %3$s, %4$s, %5$s, %6$s, %7$s or %8$s', __CLASS__ . '::setLength()', __CLASS__ . '::add()', __CLASS__ . '::clear()', __CLASS__ . '::enablePersistence()', __CLASS__ . '::get()', __CLASS__ . '::open()', __CLASS__ . '::set()', 'session_start()');
}
self::$old_session_module_name = session_module_name();
self::$backend = $backend;
self::$key_prefix = $key_prefix;
session_set_save_handler(array('fSession', 'openCache'), array('fSession', 'closeCache'), array('fSession', 'readCache'), array('fSession', 'writeCache'), array('fSession', 'destroyCache'), array('fSession', 'gcCache'));
// This ensures the session is closed before the fCache object is destructed
register_shutdown_function(array('fSession', 'close'));
}