DB Session Storage

db_session.php

<?php

/**
 * Simple Class which overwrites the session storage
 */
class Like_Saveit_Session_Handler {

	/**
	 * Store the db 
	 * @var object
	 */
	public $db;

	/**
	 * Store the session table name
	 * @var string 
	 */
	public $session_table;

	public function __construct() {
		global $wpdb;

		$wpdb->show_errors();

		$this->db = $wpdb;

		// use these class session handlers for the session
		session_set_save_handler(
				array( $this, 'sessionOpen' ), //
				array( $this, 'sessionClose' ), //
				array( $this, 'sessionRead' ), //
				array( $this, 'sessionWrite' ), //
				array( $this, 'sessionDestroy' ), //
				array( $this, 'sessionGC' ) //
		);
	}

	/**
	 * Open Session handler
	 */
	public function sessionOpen($database_name, $table_name) {
		$this->session_table = $table_name;
		return true;
	}

	/**
	 * Read Session handler
	 */
	public function sessionRead($sess_id) {

		$result = $this->db->get_row( "SELECT * FROM {$this->session_table} WHERE session_id = '{$sess_id}'", ARRAY_A );

		// if there are no results return empty string
		if ( !$result ) {
			return "";
		} else {
			return $result['session_variable'];
		}
	}

	/**
	 * Write Session handler
	 */
	public function sessionWrite($sess_id, $val) {

		$time_stamp = $this->getMicroTime();

		$result = $this->db->get_row( "SELECT session_id FROM {$this->session_table} WHERE session_id = '{$sess_id}'", ARRAY_A );

		if ( !$result ) {
			$insert = $this->db->insert(
					$this->session_table, array(
				'session_id' => $sess_id,
				'session_variable' => $val,
				'last_accessed' => $time_stamp
					)
			);
		} else {
			$update = $this->db->update(
					$this->session_table, array(
				'session_variable' => $val,
				'last_accessed' => $time_stamp
					), array( 'session_id' => $sess_id )
			);
		}
	}

	public function sessionClose() {
		return true;
	}

	public function sessionDestroy($sess_id) {
		$delete = $this->db->delete( $this->session_table, array( 'session_id' => $sess_id ) );
		return true;
	}

	public function sessionGC($max_lifetime) {
		$current_time = getMicroTime();
		$delete_query = "DELETE FROM {$session_table} WHERE last_accessed < ({$current_time} - {$max_lifetime})";
		return true;
	}

	public function getMicroTime() {
		$mtime = explode( " ", microtime() );
		return ($mtime[0] + $mtime[1]);
	}

}

//$sh = new Like_Saveit_Session_Handler;