Posted by Marek Kilimajer on 02/18/05 09:56

Greg Donald wrote:
> On Wed, 16 Feb 2005 09:36:26 -0800 (PST), Richard Lynch <ceo@l-i-e.com> wrote:
>
>>It's literally an hour's work to alter the code to use MySQL to store the
>>sessions instead of the hard drive.
>
>
> Not really, maybe 5 minutes.. here's the code:

The code misses one important thing - row locking. For concurent
requests, sess_open must block until the first request does
sess_close(). So you need to use InnoDB's row locking or
application-level GET_LOCK() and RELEASE_LOCK().

>
> Make the table in your database:
>
> CREATE TABLE `sessions` (
> `id` varchar(32) NOT NULL default '',
> `data` text NOT NULL,
> `expire` int(11) unsigned NOT NULL default '0',
> PRIMARY KEY (`id`)
> );
>
> Make a sessions.php file:
>
> <?php
>
> // MySQL database connection parameters:
> $dbhost = 'localhost';
> $dbuser = 'dbuser';
> $dbpasswd = 'dbpassword';
> $dbname = 'dbname';
>
> // Sessions table name:
> $tb_sessions = 'sessions';
>
> // Session lifetime in seconds:
> $online_expire = 900;
>
> // Use transparent sessions:
> ini_set( 'session.use_trans_sid', 1);
>
>
> // Below here should not require any changes
>
> $sdbh = '';
>
> function sess_open( $save_path, $session_name )
> {
> global $sdbh;
>
> if( ! $sdbh = mysql_pconnect( $dbhost, $dbuser, $dbpasswd ) )
> {
> echo mysql_error();
>
> exit();
> }
>
> return true;
> }
>
> function sess_close()
> {
> return true;
> }
>
> function sess_read( $key )
> {
> global $sdbh, $dbname, $tb_sessions;
>
> $sql = "
> SELECT data
> FROM $tb_sessions
> WHERE id = '$key'
> AND expire > UNIX_TIMESTAMP()
> ";
>
> $query = mysql_query( $sql ) or die( mysql_error() );
>
> if( mysql_num_rows( $query ) )
> {
> return mysql_result( $query, 0, 'data' );
> }
>
> return false;
> }
>
> function sess_write( $key, $val )
> {
> global $tb_sessions, $online_expire;
>
> $value = addslashes( $val );
>
> $sql = "
> REPLACE INTO $tb_sessions (
> id,
> data,
> expire
> ) VALUES (
> '$key',
> '$value',
> UNIX_TIMESTAMP() + $online_expire
> )
> ";
>
> return mysql_query( $sql ) or die( mysql_error() );
> }
>
> function sess_destroy( $key )
> {
> global $tb_sessions;
>
> $sql = "
> DELETE FROM $tb_sessions
> WHERE id = '$key'
> ";
>
> return mysql_query( $sql ) or die( mysql_error() );
> }
>
> function sess_gc()
> {
> global $tb_sessions;
>
> $sql = "
> DELETE FROM $tb_sessions
> WHERE expire < UNIX_TIMESTAMP()
> ";
>
> $query = mysql_query( $sql ) or die( mysql_error() );
>
> return mysql_affected_rows();
> }
>
> session_set_save_handler(
> 'sess_open',
> 'sess_close',
> 'sess_read',
> 'sess_write',
> 'sess_destroy',
> 'sess_gc'
> );
>
> session_start();
>
> $sn = session_name();
> $sid = session_id();
>
> ?>
>
> Then you just do include( 'sessions.php' );
>
> http://wiki.destiney.com/DBSessions/Install
>
>

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