PHP PDO - cannot serialize or unserialize PDO instances
Solution 1
Take a look at the __sleep and __wakeup magic methods. http://us.php.net/manual/en/language.oop5.magic.php#object.sleep
They allow you to specify which properties get serialized and which get ignored. The issue there is that you'll need to regularly pass in an instance of your PDO object.
Solution 2
PDO objects contain active links to databases (which may have a transaction initiated or db session settings and variabiles).
You cannot serialize a PDO object because the above would get lost and cannot be re-established automatically.
You should redesign your classes to access the current database link statically using a separate class (dedicated for holding db connections), instead of saving a reference in a member variable (I supose this is happening when you do new cart($connection))).
Comments
-
Run almost 4 years
I need to pass a PDO connection into a
cart
class from acontroller
,function __construct($connection) { $this->cart = new cart($connection); }
but I think the problem is with
serialize()
public function render_page() { if (!isset($_SESSION[SESSION_CART])) { $cart = $this->cart; } else { $cart = unserialize($_SESSION[SESSION_CART]); } $_SESSION[SESSION_CART] = serialize($cart); }
I get this error,
Fatal error: Uncaught exception 'PDOException' with message 'You cannot serialize or unserialize PDO instances' in C:\wamp\www\store_2012_MVC\local\controllers\class_base_extended_cart.php:89 Stack trace: #0 [internal function]: PDO->__sleep() #1 C:\wamp\www\store_2012_MVC\local\controllers\class_base_extended_cart.php(89): serialize(Object(cart)) #2 C:\wamp\www\store_2012_MVC\local\controllers\class_factory.php(75): base_extended_cart->render_page() #3 C:\wamp\www\store_2012_MVC\index.php(69): factory->render() #4 {main} thrown in C:\wamp\www\store_2012_MVC\local\controllers\class_base_extended_cart.php on line 89
How can I fix this?
Or can I use something else instead of
serialize()
?EDIT:
I tried it with
__sleep
and__wakeup
magic methods but still get the same error,class database_pdo { # database handler protected $connection = null; # make a connection public function __construct($dsn,$username,$password) { try { $this->connection = new PDO($dsn, $username, $password, array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8")); $this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); } catch (PDOException $e) { # call the get_error function $this->get_error($e); } } # don't forget to add getter method to get $this->connection, it's just a good practice. public function get_connection() { return $this->connection; } public function __sleep() { return array('connection'); } public function __wakeup() { $this->connection; } }