__get

and

__set

methods are called when there is an attempt either to use or to set a new value to any of the class property

class Person{
    public $firstName;
 
    public function __get($propertyName){
        echo "attempted to read property: $propertyName" . PHP_EOL;
    } 
    public function __set($propertyNane, $propertyValue){
        echo "attempted to set new value to property: $propertyNane" . PHP_EOL;
    } 
}
 
$p = new Person();
 
$p->firstName = 'Doe';
echo $p->firstName . PHP_EOL;
 
$p->lastName = 'John';
echo $p->lastName;

If the property is

public

, the methods are not going to be called (if the property does not exist, or exists but is not public, the methods will get called) If we make

$firstName

property

private

or

protected

, the methods will be called for the

$firstName

property

__get

,

__set

,

__call

and

__callStatic

are invoked when the method or property is inaccessible