unserialize pdo mysql error - invalid data source name - mysql

Question

I have these classes below for my online store.
This super class holds all common methods used by the child classes.
class grandpa
{
public function test1($string)
{
return $string;
}
}
So do the PDO connection,
class database_pdo extends grandpa
{
protected $connection = null;
protected $dsn,$username,$password;
public function __construct($dsn,$username,$password)
{
$this->dsn = $dsn;
$this->username = $username;
$this->password = $password;
$this->get_connection();
}
public function get_connection()
{
try
{
$this->connection = new PDO($this->dsn, $this->username, $this->password, array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));
$this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch (PDOException $e)
{
$this->get_error($e);
}
}
public function __sleep()
{
return array('dsn', 'username', 'password');
}
public function __wakeup()
{
$this->get_connection();
}
public function get_error($e)
{
$this->connection = null;
die($e->getMessage());
}
public function __destruct()
{
$this->connection = null;
}
}
I have this class extend from pdo for other common methods that require pdo connection,
class papa extends database_pdo
{
protected $connection = null;
public function __construct($connection)
{
$this->connection = $connection;
}
public function test2($string)
{
return $string;
}
}
The child classes,
class kido_1 extends papa
{
public function __construct($connection)
{
parent::__construct($connection);
}
public function test3($string)
{
return $string;
}
}
How it use the classes above,
# Host used to access DB.
define('DB_HOST', 'localhost');
# Username used to access DB.
define('DB_USER', 'xxx');
# Password for the username.
define('DB_PASS', 'xxx');
# Name of your databse.
define('DB_NAME', 'xxx');
# Data source name.
define('DSN', 'mysql:host='.DB_HOST.';dbname='.DB_NAME);
$connection = new database_pdo(DSN,DB_USER,DB_PASS);
$kido = new kido($connection);
$_SESSION['cart'] = serialize($kido);
$kido = unserialize($_SESSION['cart']);
print_r($kido->test3('hello'));
I get this error,
invalid data source name
It is caused by unserialize() that I need it for my cart data...
How can I fix this? Or a better way of rewrite these classes?

Answer 1

Your papa::connection is a PDO object. Therefore, when you are trying to serialize $kido, you are trying to serialize a resource, which is not possible.
Try adding a $this->connection = null; in your database_pdo::__sleep() method.

Answer 2

a solution I think...
class papa extends grandpa
{
protected $connection = null;
public function __construct($connection)
{
$this->connection = $connection;
}
public function test2($string)
{
return $string;
}
}