PHP Sessions & MySQL (Custom Session Handler)

[toneeedavis]

Hi Guys,

I am currently trying to write a bit of code that handles the sessions in a mysql database.

• Setting the Data - Worknig Fine

• Reading the Data - Clears the session data

I am having problems with reading the data back again. When i try this it clears the data stored in teh session.

Here is the code for my Session Class:

<?php

    /**
     * File         : session.lib..php
     * Project      : Sessions
     * Author       : AD
     * Description  : Sessions stored into the database
     * Version      : 1.0 - 27/07/2009 - Initial Creation
     **/

    class SessionManager 
    {

            var $life_time;

            function SessionManager() 
            {

                    // 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->sql = new Site_Sql;              // Initiates the sql class
            }

            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();

                    $this->sql->Connect();

                    $_query = sprintf("SELECT session_data FROM tbl_sessions WHERE session_id='%s' AND expires > '%s'", mysql_escape_string($id), mysql_escape_string($time));

                    //debug
                    echo $_query;

                    $results = $this->sql->Query($_query);

                    $row_count = $results->FetchNUM();                          

                    if($row_count > 0) 
                    {
                            $row= $results->FetchRow();
                            $data = $row['session_data'];

                    }       

                    $this->sql->Close();

                    return $data;

            }

            function write( $id, $data ) 
            {

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

                    $this->sql->Connect();

                    $_query = sprintf("INSERT INTO tbl_sessions (session_id, session_data, expires) VALUES ('%s', '%s', '%s') ON DUPLICATE KEY UPDATE session_data='%s', expires='%s'", mysql_escape_string($id), mysql_escape_string($data), mysql_escape_string($time), mysql_escape_string($data), mysql_escape_string($time));

                     // Debug
                    echo $_query;

                    $results = $this->sql->Query($_query);

                    $this->sql->Close();

                    return TRUE;
            }

            function destroy( $id ) 
            {

                    // Build query
                    $newid = mysql_real_escape_string($id);

                    $this->sql->Connect();

                    $_query = sprintf("DELETE FROM tbl_sessions WHERE session_id='%s'", mysql_escape_string($id));

                    // debug
                    echo $_query;

                    $results = $this->sql->Query($_query);

                    $this->sql->Close();

                    return TRUE;
            }

            function gc() 
            {

                    // Garbage Collection

                    $this->sql->Connect();

                    $_query = sprintf("DELETE FROM tbl_sessions WHERE expires < UNIX_TIMESTAMP()");

                    //debug
                    echo $_query;

                    $results = $this->sql->Query($_query);

                    $this->sql->Close();

                    // Always return TRUE
                    return true;
            }
    }

?>

and here is the code to set the session:

<?php  

echo "Sessions<br><br>";

echo "Creating Session: info...";



$SessionManager= new SessionManager;
session_start();

$_SESSION['info'] = "This is a variable in a session";

echo "...Done<br><br>";

echo "Click <a href=\"view.php\">here</a> to view the session<br><br>";

echo "Debug:<br><br>";


session_write_close();

?>

and the code for viewing the session:

<?php  

echo "Sessions<br><br>";

$SessionManager= new SessionManager;
session_start();

echo "Session Name: info<br>";
echo "Session Data: " . $_SESSION['infooo'] . "<br><br>";

echo "Click <a href=\"del.php\">here</a> to delete the session<br><br>";

echo "Debug:<br><br>";


?>

I hope someone can help me with this as its driving me up the wall!

Thankyou in advance.

Tony

[NogDog]

Could it simply be that you misspelled "info" as "infooo" in the last piece of code you posted?

[toneeedavis]

Haha, nope, i was doing some testing, must have forgotten to change it back, still having the same problems.

Tony

[Weedpacket]

Hang on; what exactly is the criterion that gc() uses to decide if a session is old enough to be deleted?

[NogDog]

Weedpacket;10923122 wrote:

Hang on; what exactly is the criterion that gc() uses to decide if a session is old enough to be deleted?

Ooh...good catch. It looks like gc() would be deleting any data that wasn't saved less than a second ago.

[toneeedavis]

Hi Guys,

Thanks for all of your efforts on this...

GC isnt the problem, have commented it all out, but the session data is being removed from the db.

mysql> select * from tbl_sessions;
+----------------------------+----------------------------------------------+------------+
| session_id                   | session_data                                    | expires    |
+----------------------------+----------------------------------------------+------------+
| XXXXXXXXXXXXXXXXX | info|s:31:"This is a variable in a session"; | 1248763183 | 
+----------------------------+----------------------------------------------+------------+
1 row in set (0.00 sec)

i then go to the view page, and for some reason it runs the write functions because i get this output for the sql query:

INSERT INTO tbl_sessions (session_id, session_data, expires) VALUES ('XXXXXXXXXXXXXXXXX', '', '1248763189') ON DUPLICATE KEY UPDATE session_data='', expires='1248763189'

As you can see the session_data field is empty, but i dont know why, is my sql query wrong?

after that the database looks like this:

mysql> select * from tbl_sessions;
+----------------------------+----------------------------------------------+------------+
| session_id                   | session_data                                    | expires    |
+----------------------------+----------------------------------------------+------------+
| XXXXXXXXXXXXXXXXX |                                                           | 1248763183 | 
+----------------------------+----------------------------------------------+------------+
1 row in set (0.00 sec)

[toneeedavis]

Hi Guys,

Iv now found the problem, when the read is done its not returning a value, because i have the wrong array in there, it should read row[0] rather than row['session_data'].

ALL FIXED AND WORKING 🙂

Thanks for everyones help.

Kind Regards

Tony

[NogDog]

Glad you found the problem, even if we didn't.

Don't forget to mark this thread "resolved" (if it is) via the "Thread Tools" link near the top.

[Bjom]

You might have a look at my custom session handler - as an inspiration if it helps, or if you find any flaws - I'm happy about any code review that I can get...or....simply use it if you like it.

http://code.google.com/p/pagebricks/

Bjom