Examples

Examples – Examples for the usage of Event_Dispatcher

Examples usage of Event_Dispatcher

The following examples show you how to use Event_Dispatcher to create more flexible applications.

Basic example

<?php
require_once 'Event/Dispatcher.php';
    
/**
 * Dummy class that simulated authentication
 */
class Auth
{
    var 
$_dispatcher null;
    var 
$_user;
    
    function 
Auth(&$dispatcher)
    {
         
$this->_dispatcher = &$dispatcher;
    }
    
    function 
login($username$password)
    {
        
// Your code that authenticates goes here
        // ....
        // imagine $this->_user contains a User object
        
        
$this->_dispatcher->post($this->_user'onLogin');
    }
}

function 
logAuth(&$notification)
{
    
$user = &$notification->getNotificationObject();
    
$username $user->getUsername();
    
    
// write logfile
    
error_log("$username logged in."3'/tmp/auth.log');
}

$dispatcher = &Event_Dispatcher::getInstance();

// catch all onLogin events to write a logfile
$dispatcher->addObserver('logAuth''onLogin');

$auth = &new Auth($dispatcher);

// simulate login
$auth->login($_GET['user'], $_GET['pass']);
?>

In this example, Event_Dispatcher is used to allow observers to hook into the authentication process. Whenever a user authenticates, a notification onLogin is sent.

This can be used to write logfiles or block the application for other users.

Cancelling notifications

<?php
require_once 'Event/Dispatcher.php';
    
/**
 * Dummy class that simulated authentication
 */
class Auth
{
    var 
$_dispatcher null;
    var 
$_user;
    
    function 
Auth(&$dispatcher)
    {
         
$this->_dispatcher = &$dispatcher;
    }
    
    function 
login($username$password)
    {
        
// Your code that authenticates goes here
        // ....
        // imagine $this->_user contains a User object
        
        
$notification $this->_dispatcher->post($this->_user'onLogin');
        
        if (
$notification->isNotificationCancelled()) {
            echo 
"You are not allowed to login";
            
$this->_user->logout();
        }
    }
}

function 
logAuth(&$notification)
{
    
$user = &$notification->getNotificationObject();
    
$username $user->getUsername();
    
    
// If a special user authenticated, cancel
    // the notification
    
if ($username === 'foo') {
        
$notification->cancelNotification();
    } else {
        
// write logfile
        
error_log("$username logged in."3'/tmp/auth.log');
    }
}

$dispatcher = &Event_Dispatcher::getInstance();

// catch all onLogin events to write a logfile
$dispatcher->addObserver('logAuth''onLogin');

$auth = &new Auth($dispatcher);

// simulate login
$auth->login($_GET['user'], $_GET['pass']);
?>

In this case, the cancelNotification() method is used to cancel the notification if a certain user tries to authenticate.

The login method has been changed as well to check whether the notification has been cancelled and to take the necessary steps.

This allows you to add some flexible rules to your authentication system.

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Last updated: Thu, 18 Dec 2014 — Download Documentation
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