When do/should I use __construct(), __get(), __set(), and __call() in PHP?

Question

A similar question discusses __construct, but I left it in my title for people searching who find this one.

Apparently, __get and __set take a parameter that is the

Answer 1

Overloading methods is especially useful when working with PHP objects that contain data that should be easily accessable. __get() is called when accessing a non-existent propery, __set() is called when trying to write a non-existent property and __call() is called when a non-existent method is invoked.

For example, imagine having a class managing your config:

class Config
{
    protected $_data = array();

    public function __set($key, $val)
    {
        $this->_data[$key] = $val;
    }

    public function __get($key)
    {
        return $this->_data[$key];
    }

    ...etc

}

This makes it a lot easier to read and write to the object, and gives you the change to use custom functionality when reading or writing to object. Example:

$config = new Config();
$config->foo = 'bar';

echo $config->foo; // returns 'bar'