Session lib - Printable Version

Code:
&lt;?php

/*



CREATE TABLE `<insert table name>` (

  `sid` char(32) NOT NULL,

  `expire` int(11) NOT NULL,

  `value` text NOT NULL,

  PRIMARY KEY  (`sid`)

) ENGINE=MyISAM DEFAULT CHARSET=utf8;



*/



class Session 

{

    var $CI;



    

/*

class constructor. sets the callback functions for using 

a database with the session. Sets the session name and starts the 

session.

*/    

    function __construct()

    {        

        $this->CI =& get_instance();

        session_set_save_handler(array(&$this, "open"), 

                                        array(&$this, "close"),

                                array(&$this, "select"),

                              array(&$this, "write"),

                            array(&$this, "destroy"),

                                array(&$this, "gc"));

                                

     

      session_name($this->CI->config->item('sess_cookie_name'));

        session_start();

    }

    

    

/*

class destructor. Does nothing yet

*/    

    function __destruct()

    {

        /*session_write_close();*/

    }    

    

/*

* Don't do anything as I dont open a db

* The assumption is that the db has been autoloaded

*/

    function open($session_path, $session_name) 

    {

        return 1;

    }

    

/*

* Doesn't actually do anything as I don't close the db

* allow the script ending to auto close db connections

*/

    function close() 

    {

        return 1;

    }

    

/*

* Reads the session data from the database

*/

    function select($SID) 

    {

        $where = array('sid' => $SID, 'expire >' => time());

       $this->CI->db->select('value');

       $query = $this->CI->db->get($this->CI->config->item('sess_table_name'));

       

       $row = $query->row();

       return $row->value;

    } 

    

/*

* This function writes the session data to the database.

* If that SID already exists, then the existing data will be updated.

*/

    function write($SID, $value) 

    {

    

            

       $expiration = time() + $this->CI->config->item('sess_expiration');       

       $query = "INSERT INTO " . $this->CI->config->item('sess_table_name') . 

                                          " VALUES('$SID', '$expiration', '$value')";

            

      if( !$this->CI->db->simple_query($query))

      {

          $query = "UPDATE " . $this->CI->config->item('sess_table_name') . 

                                                       " SET expire='" . $expiration . 

                                     "', value='" . $value . "' WHERE sid='". $SID . 

                                                       "' AND expire > '". time() . "'";

           $this->CI->db->query($query);

      }    

    } 

    

    

/*

* Deletes all session information having input SID (only one row)

*/

    function destroy($SID) 

    {

        $query = "DELETE FROM " . $this->CI->config->item('sess_table_name') . " WHERE sid = '$SID'";

       $this->CI->db->query($query);

    } 

    

/*

* Deletes all sessions that have expired.

*/

    function gc($lifetime) 

    {

        $query = "DELETE FROM " . $this->CI->config->item('sess_table_name') . " WHERE expire < " . time();

       $this->CI->db->query($query);

       return $query->num_rows();

    }



}//end class

?&gt;