What is __get()

class Penguin extends Animal {

	public function __construct($id) {
		$this->getPenguinFromDb($id);
	}

	public function getPenguinFromDb($id) {
	// elegant and robust database code goes here
	}
}

Now if our penguin has the properties “name” and “age” after it is loaded, we’d be able to do:

$tux = new Penguin(3);
echo $tux->name . " is " . $tux->age . " years old\n";

However imagine something changed about the backend database or information provider, so instead of “name”, the property was called “username”. And imagine this is a complex application which refers to the “name” property in too many places for us to change. We can use the __get method to pretend that the “name” property still exists:

class Penguin extends Animal {

	public function __construct($id) {
		$this->getPenguinFromDb($id);
	}

	public function getPenguinFromDb($id) {
	// elegant and robust database code goes here
	}

	public function __get($field) {
		if($field == 'name') {
			return $this->username;
	}
}

This technique isn’t really a good way to write whole systems, because it makes code hard to debug, but it is a very valuable tool. It can also be used to only load properties on demand or show calculated fields as properties, and a hundred other applications that I haven’t even thought of!