Page 253 - Beginning PHP 5.3

Chapter 8: Objects
In a real - world situation, make sure you don ’ t transmit sensitive information such as usernames as
passwords as plain text strings if there ’ s a chance that the data might be intercepted or read by
untrusted third parties.
If you do need to preserve all your object ’ s properties, you can use the built - in get_object_vars()
function to get an associative array of all the properties in the object, then use the array_keys() function
to get just the property names as an array, which you can then return from your __sleep() method:

class User {
public $username;
public $password;
public $loginsToday;

public function __sleep() {
// (Clean up; close database handles, etc)
return array_keys( get_object_vars( $this ) );

}
}

Finally, here ’ s an example that shows the __wakeup() method in action:
class User {
public function __wakeup() {
echo “Yawn... what’s for breakfast? < br / > ”;
}
}

$user = new User;
$userString = serialize( $user );
$obj = unserialize( $userString ); // Displays “Yawn... what’s for breakfast?”

Determining an Object ’ s Class

Earlier in the chapter you learned that you can use hints in method and function arguments to ensure
that the correct class of object is being passed. Sometimes, though, you might want to explicitly
check the class of a particular object that you ’ re working with. For example, you might want to check
that all the objects in an array are of a certain class, or treat objects differently depending on their class.

To find out the class of an object, you can use PHP ’ s built - in get_class() function, as follows:

class MyClass {
}

$obj = new MyClass();

echo get_class( $obj ); // Displays “MyClass”

215

c08.indd 215
c08.indd 215 9/21/09 9:03:48 AM
9/21/09 9:03:48 AM