Why can't a PDO object be serialized?

Question

I am making a multi-threaded CLI-PHP application and need to serialize PDO object to pass it between work inside the thread, and wake it up from a sleeping thre

Answer 1

What's being done at http://php.net/manual/en/language.oop5.magic.php is creating a wrapper that can be serialized since the PDO link itself cannot be.

dsn = $dsn;
        $this->username = $username;
        $this->password = $password;
        $this->connect();
    }

    private function connect()
    {
        $this->link = new PDO($this->dsn, $this->username, $this->password);
    }

    public function __sleep()
    {
        return array('dsn', 'username', 'password');
    }

    public function __wakeup()
    {
        $this->connect();
    }
}?>

The PDO object apparently does not keep the dsn, user, pwd after connecting, and so cannot be directly serialized. But if you created a wrapper like in the example above, where you stored this information, you could serialize the wrapper. Then when you unserialize, it will create a new PDO object and reconnect by passing the credentials in from the wrapper to PDO.