<?php

        $m_host = ""; //MySQL Host
        $m_user = ""; //MySQL User
        $m_pass = ""; //MySQL Pass
        $m_db   = ""; //MySQL Database

        $session_expire = 600; // Session expire time, in seconds (minutes * 60 = seconds)

        $gc_probability = 50; // Probability that the garbage collection function will be called. 50% chance by default

        ini_set("session.gc_probability",$gc_probability);

        /* Open function; Opens/starts session

        Opens a connection to the database and stays open until specifically closed
        This function is called first and with each page load */

        function open ($s,$n) // do not modify function parameters
        {
                global $session_connection, $m_host, $m_user, $m_pass, $m_db;
                $session_connection = mysql_pconnect($m_host,$m_user,$m_pass);
                mysql_select_db($m_db,$session_connection);
                return true;
        }

        /* Read function; downloads data from repository to current session

        Queries the mysql database, unencrypts data, and returns it.
        This function is called after 'open' with each page load. */
        function read ($id) // do not modify function parameters
        {
                global $session_connection,$session_read;
                $query = "SELECT data FROM sess_data WHERE id=\"{$id}\"";
                $res = mysql_query($query,$session_connection);
                if(mysql_num_rows($res) != 1) return ""; // must return string, not 'false'
                else
                {
                        $session_read = mysql_fetch_assoc($res);
                        $session_read["data"] = base64_decode($session_read["data"]);
                        return $session_read["data"];
                }
        }


/* Write function; uploads data from current session to repository

        Inserts/updates mysql records of current session. Called after 'read'
        with each page load */
        function write ($id,$data) // do not modify function parameters
        {
                if(!$data) { return false; }
                global $session_connection, $session_read, $session_expire;
                $expire = time() + $session_expire;
                $data = mysql_real_escape_string(base64_encode($data));
                if($session_read) $query = "UPDATE sess_data SET data=\"{$data}\", expire=\"{$expire}\" WHERE id=\"{$id}\"";
                else $query = "INSERT INTO sess_data SET id=\"{$id}\", data=\"{$data}\"";
                mysql_query($query,$session_connection);
                return true;
        }

        /*Close function; closes session

        closes mysql connection */
        function close ()
        {
                global $session_connection;
                mysql_close($session_connection);
                return true;
        }


        /* destroy function; deletes session data

        deletes records of current session. called ONLY when function 'session_destroy()'
        is called */
        function destroy ($id) // do not modify function parameters
        {
                global $session_connection;
                $query = "DELETE FROM sess_data WHERE id=\"{$id}\"";
                mysql_query($query,$session_connection);
                return true;
        }

        /* gc function; cleans expired sessions

        deletes all rows where expire < time(); called with a $gc_probability chance of executing */
        function gc ($expire)
        {
                global $session_connection;
                $query = "DELETE FROM sess_data WHERE expire < ".time();
                mysql_query($query,$session_connection);
        }


        // Set custom handlers
        session_set_save_handler ("open", "close", "read", "write", "destroy", "gc");

        // Start session
        session_start();
?>

// MySQL Database Description

create table sess_data (
id2 int not null auto_increment,
id text not null,
data text,
expire int not null,
primary key(id2)
);