Implementing observer pattern in PHP
// Implementation function: Notify security module and advertising module when logging in
// Predefined interface: SplObserver observer and SplSubject observer
class User implements SplSubject
{
protected $login_num;
protected $hobby;
protected $_subject;
public function __construct($login_num, $hobby)
{
$this->login_num = $login_num;
$this->hobby = $hobby;
//Storage observer object
$this->_subject = new SplObjectStorage();
}
public function __get($name)
{
// TODO: Implement __get() method.
return $this->$name;
}
public function login()
{
// Operation...
$this->notify();
}
// SplSubject interface
public function attach(SplObserver $observer)
{
// TODO: Implement attach() method.
$this->_subject->attach($ observer);
}
public function detach(SplObserver $observer)
{
// TODO: Implement detach() method.
$this->_subject->detach($observer);
}
public function notify()
{
/ / TODO: Implement notify() method.
foreach ($this->_subject as $observer) {
$observer->update($this);
}
}
}
// The observer observes user login here
// Security check
class safe implements SplObserver
{
public function update(SplSubject $subject)
{
// TODO: Implement update() method.
if ($subject->login_num > 10) {
echo 'You have logged in more than 10 times today. There may be a password leak problem. Please reset your password! ';
} else {
echo 'Today's' . $subject->login_num . 'Safe login! ';
}
}
}
// Advertising promotion
class ad implements SplObserver
{
public function update(SplSubject $subject)
{
// TODO: Implement update() method.
if ($subject-> hobby == 'sports') {
echo 'This is a sports advertisement! ';
} else {
echo 'Random ad! ';
}
}
}
$hobby = ['sports', 'eat', 'drink', 'sleep', ' play'];
$user = new User(random_int(1, 20), $hobby[shuffle($hobby)]);
$user->attach(new safe( ));
$user->attach(new ad());
// A series of observers are triggered when the user logs in
$user->login ();
