I've been trying to use database sessions in a project I'm working on but so far its not working out. The session is created just fine, but it refuses to store anything. When I look at the database entry the session_data field is always empty.

Here is the code I'm using to manage my sessions:

PHP Code:

<?php
class SessionManager {
    
    var $life_time;
    var $conn;
    
   function __construct() 
   {
      // Read the maxlifetime setting from PHP
      $this->life_time = get_cfg_var("session.gc_maxlifetime");
      // Register this object as the session handler
      session_set_save_handler( 
        array( &$this, "open" ), 
        array( &$this, "close" ),
        array( &$this, "read" ),
        array( &$this, "write"),
        array( &$this, "destroy"),
        array( &$this, "gc" ));
        
        $this->conn = mysql_connect('host', 'user', 'pass');
        mysql_select_db('table', $this->conn);
   }
   
    function open( $save_path, $session_name )
    {
        global $sess_save_path;
        $sess_save_path = $save_path;
        // Don't need to do anything. Just return TRUE.
        return true;
    }

    function close() 
    {
        return true;
    }

    function read( $id ) 
    {
        // Set empty result
        $data = '';

        // Fetch session data from the selected database

        $time = time();

        $newid = @mysql_real_escape_string($id, $this->conn);
        $sql = "SELECT `session_data` FROM `sessions` WHERE 
                `session_id` = '$newid' AND `expires` > $time";

        $result = @mysql_query($sql, $this->conn);                           
        $count = @mysql_num_rows($result);

        if($count > 0) 
        {     
            $row = @mysql_fetch_assoc($result, MYSQL_ASSOC);
            $data = $row['session_data'];
        }

        return $data;
    }
    
     function write( $id, $data ) 
     {

         // Build query                
         $time = time() + $this->life_time;

         $newid = mysql_real_escape_string($id, $this->conn);
         $newdata = mysql_real_escape_string($data, $this->conn);

         $sql = "REPLACE INTO `sessions`
(`session_id`,`session_data`,`expires`) VALUES('$newid',
'$newdata', $time)";

         if(!$rs = @mysql_query($sql, $this->conn))
             return false;

         return true;
     }
     
     function destroy( $id ) {

         // Build query
         $newid = mysql_real_escape_string($id, $this->conn);
         $sql = "DELETE FROM `sessions` WHERE `session_id` =
'$newid'";

         @mysql_query($sql, $this->conn);

         return true;

      }
      
      function gc() {

         // Garbage Collection
         // Build DELETE query.  Delete all records who have passed the expiration time
         $sql = 'DELETE FROM `sessions` WHERE `expires` <
UNIX_TIMESTAMP();';

         @mysql_query($sql, $this->conn);

         // Always return TRUE
         return true;

      }
    
}
?>

and here is the code I'm using to test it:

PHP Code:

require_once('include/session.php');
$sess = new SessionManager();
session_start();
$_SESSION['username'] = $username;

header('Location: redirect.php?loc=home'); 


PHP Code:

require_once('include/session.php');
$sess = new SessionManager();
session_start();
echo $_SESSION['username']; 


In this case there is no output and when I look in the database this is what I see:

session_id                         | session_data | expires
27d13b0d405f9c9547fe5090baa34d6f                    1221342837

If anyone has some insight as to what my problem is I'd appreciate it.

I personally used this, with a mysql db some years ago:
It may not be the cleanest code, nor totally fool proofed, but it worked ok.
I didn't see anything wrong in your code, but I'm a bit sleepy, so it may have passed through.

In a prepended file, to declare the:

PHP Code:

session_set_save_handler('_sessOpen', 
                         '_sessClose', 
                         '_sessRead', 
                         '_sessWrite', 
                         '_sessDestroy', 
                         '_sessClean'); 
                         
session_start(); 


mysqlSession.php:

PHP Code:

<?php

/*********************************************
** $RCSfile: auth.php,v $
** $Revision: 157 $
** $Date: 2006-10-11 19:27:36Z $
** $Author: tmo $
** Client : fcs
** Creation date: 10 août 06 14:35:07
** Usage : 
** Short description : 
*********************************************/

/*
 * MYSQL session save handler
 * Store the sessions in an SQL database.
 *  

CREATE TABLE sessions
(
    id varchar(32) NOT NULL,
    access int(10) unsigned,
    data text,
    PRIMARY KEY (id)
);
*/
$GLOBALS['debug']=FALSE;
function _sessOpen() { 
    if($GLOBALS['debug']===TRUE){
        echo"<pre>".print_r(func_get_args(),1)."</pre>";
        _sessReport('open');
    }
    $db=sessDbConnect();
    
    if(!$GLOBALS['_sess_db']){
        echo mysql_error();
        die('_open');
    } 
    else{
      return true;
    } 
    return FALSE; 
} 

function sessDbConnect(){
    $db=mysql_connect(DB_HOST, DB_USER, DB_PWD);
    $tbl=mysql_select_db(DB_NAME, $db);
    $GLOBALS['_sess_db']=&$db;
    return $db;
}

function _sessClose(){ 
    if($GLOBALS['debug']===TRUE){
        echo"<pre>".print_r(func_get_args(),1)."</pre>";
        _sessReport('close');
    }
    return mysql_close(sessDbConnect()); 
} 

function _sessRead($id){ 
    if($GLOBALS['debug']===TRUE){
        echo"<pre>".print_r(func_get_args(),1)."</pre>";
        _sessReport('read');
    }
    $id = mysql_real_escape_string($id); 
    $sql = "SELECT data 
            FROM   sessions 
            WHERE  id = '$id'"; 
    if ($result = mysql_query($sql, sessDbConnect())){
        if (mysql_num_rows($result)){ 
                $record = mysql_fetch_assoc($result); 
                return $record['data']; 
        } 
    }
    else{
        echo mysql_error();
        die('_READ');
    } 
    return ''; 
} 

function _sessWrite($id, $data){ 
    if($GLOBALS['debug']===TRUE){
        echo"<pre>".print_r(func_get_args(),1)."</pre>";
        _sessReport('write');
    }
    $access = time(); 
    $id = mysql_real_escape_string($id); 
    $access = mysql_real_escape_string($access); 
    $data = mysql_real_escape_string($data); 
    $sql = "REPLACE  
          INTO    sessions 
          VALUES  ('$id', '$access', '$data')";
    $ret=mysql_query($sql, sessDbConnect());
    if(!$ret){
        echo mysql_error();
        die('_WRITE');
    } 
    return $ret;
} 

function _sessDestroy($id){ 
    if($GLOBALS['debug']===TRUE){
        echo"<pre>".print_r(func_get_args(),1)."</pre>";
        _sessReport('destroy');
    }
    $id = mysql_real_escape_string($id); 
    $sql = "DELETE 
            FROM   sessions 
            WHERE  id = '$id'"; 
    $ret=mysql_query($sql, sessDbConnect());
    if(!$ret){
        echo mysql_error();
        die('_DESTROY');
    } 
    return $ret; 
} 

function _sessClean($max){ 
    if($GLOBALS['debug']===TRUE){
        echo"<pre>".print_r(func_get_args(),1)."</pre>";
        _sessReport('clean');
    }
    $old = time() - $max; 
    $old = mysql_real_escape_string($old); 
    $sql = "DELETE 
            FROM   sessions 
            WHERE  access < '$old'"; 
    $ret=mysql_query($sql, sessDbConnect()); 
    if(!$ret){
        echo mysql_error();
        die('_CLEAN');
    } 
    return $ret;
} 

function _sessReport($str){
    //echo("\n<br/>".$str);
}

I tried your code in place of mine and I have the same problem.