Setting up redis-backed sessions in PHP

redis_session_setup.php

<?php

$redis_session_handle = null ;

function redis_session_get_connection () {
    global $redis_session_handle ;
    if (!$redis_session_handle) {
        require_once (__DIR__ . '/../libs/Rediska.php') ;
        $redis_session_handle = new Rediska (array (
            'servers' => array (
                array (
                    'host' => REDIS_HOST,
                    'port' => REDIS_PORT,
                    'db'   => REDIS_DB,
                ),
            )
        )) ;
    }
    return $redis_session_handle ;
}

function redis_session_read ($id) {
    $redis = redis_session_get_connection () ;
    return $redis -> get ('sessions:php:' . $id) ;
}

function redis_session_write ($id, $data) {
    $redis = redis_session_get_connection () ;
    $redis -> setAndExpire ('sessions:php:' . $id, $data, ini_get ("session.gc_maxlifetime")) ;
    return true ;
}

function redis_session_destroy ($id) {
    $redis = redis_session_get_connection () ;
    $redis -> delete ('sessions:php:' . $id) ;
    return true ;	
}

function redis_session_open ($save_path, $session_name) {
    return true ;
}

function redis_session_close () {
    return true ;
}

function redis_session_gc ($maxlifetime) {
    return true ;
}

session_set_save_handler (
    "redis_session_open",
    "redis_session_close",
    "redis_session_read",
    "redis_session_write",
    "redis_session_destroy",
    "redis_session_gc"
);

?>