PHP hook, building hooks in your application
Introduction
One of the real challenges in building any type of framework, core or application is making it possible for the developers to hook into the business logic at specific points. Since PHP is not event based, nor it works with interrupts you have to come up an alternative.
The test case
Lets assume we are the main developers of a webshop framework. Programmers can use our framework to build complete webshops. Programmers can manage the orders that are placed on the webshop with the order class. The order class is part of our framework and we don’t want it to be extended by any programmer. However we don’t want to limit to programmers in their possibilities to hook into the orders process.
For example programmers should be able to send an email to the webshopowner if an order changes from one specific delivery status to another. This functionality is not part of the default behavior in our framework and is custom for the progammers webshop implementation.
Like said before, PHP doesn’t provide interrupts or real events so we need to come up with another way to implement hooks into our application. Lets take a look at the observer pattern.
Implementing the Observer pattern
The observer pattern is a design-pattern that describes a way for objects to be notified to specific state-changes in objects of the application.
For the first implementation we can use SPL. The SPL provides in two simple objects:
SPLSubject
- attach (new observer to attach)
- detach (existing observer to detach)
- notify (notify all observers)
SPLObserver
- update (Called from the subject (i.e. when it’s value has changed).
iOrderRef = $iOrderRef;
// Get order information from the database or an other resources
$this->iStatus = Order::STATUS_SHIPPED;
}
/**
* Attach an observer
*
* @param SplObserver $oObserver
* @return void
*/
public function attach(SplObserver $oObserver)
{
$sHash = spl_object_hash($oObserver);
if (isset($this->aObservers[$sHash])) {
throw new Exception('Observer is already attached');
}
$this->aObservers[$sHash] = $oObserver;
}
/**
* Detach observer
*
* @param SplObserver $oObserver
* @return void
*/
public function detach(SplObserver $oObserver)
{
$sHash = spl_object_hash($oObserver);
if (!isset($this->aObservers[$sHash])) {
throw new Exception('Observer not attached');
}
unset($this->aObservers[$sHash]);
}
/**
* Notify the attached observers
*
* @param string $sEvent, name of the event
* @param mixed $mData, optional data that is not directly available for the observers
* @return void
*/
public function notify()
{
foreach ($this->aObservers as $oObserver) {
try {
$oObserver->update($this);
} catch(Exception $e) {
}
}
}
/**
* Add an order
*
* @param array $aOrder
* @return void
*/
public function delete()
{
$this->notify();
}
/**
* Return the order reference number
*
* @return int
*/
public function getRef()
{
return $this->iOrderRef;
}
/**
* Return the current order status
*
* @return int
*/
public function getStatus()
{
return $this->iStatus;
}
/**
* Update the order status
*/
public function updateStatus($iStatus)
{
$this->notify();
// ...
$this->iStatus = $iStatus;
// ...
$this->notify();
}
}
/**
* Order status handler, observer that sends an email to secretary
* if the status of an order changes from shipped to delivered, so the
* secratary can make a phone call to our customer to ask for his opinion about the service
*
* @package Shop
*/
class OrderStatusHandler implements SplObserver
{
/**
* Previous orderstatus
* @var int
*/
protected $iPreviousOrderStatus;
/**
* Current orderstatus
* @var int
*/
protected $iCurrentOrderStatus;
/**
* Update, called by the observable object order
*
* @param Observable_Interface $oSubject
* @param string $sEvent
* @param mixed $mData
* @return void
*/
public function update(SplSubject $oSubject)
{
if(!$oSubject instanceof Order) {
return;
}
if(is_null($this->iPreviousOrderStatus)) {
$this->iPreviousOrderStatus = $oSubject->getStatus();
} else {
$this->iCurrentOrderStatus = $oSubject->getStatus();
if($this->iPreviousOrderStatus === Order::STATUS_SHIPPED && $this->iCurrentOrderStatus === Order::STATUS_DELIVERED) {
$sSubject = sprintf('Order number %d is shipped', $oSubject->getRef());
//mail('secratary@example.com', 'Order number %d is shipped', 'Text');
echo 'Mail sended to the secratary to help her remember to call our customer for a survey.';
}
}
}
}
$oOrder = new Order(26012011);
$oOrder->attach(new OrderStatusHandler());
$oOrder->updateStatus(Order::STATUS_DELIVERED);
$oOrder->delete();
?>
There are several problems with the implementation above. To most important disadvantage is that we have only one update method in our observer. In this update method we don’t know when and why we are getting notified, just that something happened. We should keep track of everything that happens in the subject. (Or use debug_backtrace… just joking, don’t even think about using it that way ever!).
Taking it a step further, events
Lets take a look at the next example, we will extend the Observer implementation with some an additional parameter for the eventname that occured.
Finishing up, optional data
iOrderRef = $iOrderRef;
// Get order information from the database or something else...
$this->iStatus = Order::STATUS_SHIPPED;
}
/**
* Attach an observer
*
* @param Observer_Interface $oObserver
* @return void
*/
public function attachObserver(Observer_Interface $oObserver)
{
$sHash = spl_object_hash($oObserver);
if (isset($this->aObservers[$sHash])) {
throw new Exception('Observer is already attached');
}
$this->aObservers[$sHash] = $oObserver;
}
/**
* Detach observer
*
* @param Observer_Interface $oObserver
* @return void
*/
public function detachObserver(Observer_Interface $oObserver)
{
$sHash = spl_object_hash($oObserver);
if (!isset($this->aObservers[$sHash])) {
throw new Exception('Observer not attached');
}
unset($this->aObservers[$sHash]);
}
/**
* Notify the attached observers
*
* @param string $sEvent, name of the event
* @param mixed $mData, optional data that is not directly available for the observers
* @return void
*/
public function notifyObserver($sEvent, $mData=null)
{
foreach ($this->aObservers as $oObserver) {
try {
$oObserver->update($this, $sEvent, $mData);
} catch(Exception $e) {
}
}
}
/**
* Add an order
*
* @param array $aOrder
* @return void
*/
public function add($aOrder = array())
{
$this->notifyObserver('onAdd');
}
/**
* Return the order reference number
*
* @return int
*/
public function getRef()
{
return $this->iOrderRef;
}
/**
* Return the current order status
*
* @return int
*/
public function getStatus()
{
return $this->iStatus;
}
/**
* Update the order status
*/
public function updateStatus($iStatus)
{
$this->notifyObserver('onBeforeUpdateStatus');
// ...
$this->iStatus = $iStatus;
// ...
$this->notifyObserver('onAfterUpdateStatus');
}
}
/**
* Order status handler, observer that sends an email to secretary
* if the status of an order changes from shipped to delivered, so the
* secratary can make a phone call to our customer to ask for his opinion about the service
*
* @package Shop
*/
class OrderStatusHandler implements Observer_Interface
{
protected $iPreviousOrderStatus;
protected $iCurrentOrderStatus;
/**
* Update, called by the observable object order
*
* @param Observable_Interface $oObservable
* @param string $sEvent
* @param mixed $mData
* @return void
*/
public function update(Observable_Interface $oObservable, $sEvent, $mData=null)
{
if(!$oObservable instanceof Order) {
return;
}
switch($sEvent) {
case 'onBeforeUpdateStatus':
$this->iPreviousOrderStatus = $oObservable->getStatus();
return;
case 'onAfterUpdateStatus':
$this->iCurrentOrderStatus = $oObservable->getStatus();
if($this->iPreviousOrderStatus === Order::STATUS_SHIPPED && $this->iCurrentOrderStatus === Order::STATUS_DELIVERED) {
$sSubject = sprintf('Order number %d is shipped', $oObservable->getRef());
//mail('secratary@example.com', 'Order number %d is shipped', 'Text');
echo 'Mail sended to the secratary to help her remember to call our customer for a survey.';
}
}
}
}
$oOrder = new Order(26012011);
$oOrder->attachObserver(new OrderStatusHandler());
$oOrder->updateStatus(Order::STATUS_DELIVERED);
$oOrder->add();
?>
Now we are able to take action on different events that occur.
Disadvantages
Although this implementation works quite well there are some drawbacks. One of those drawbacks is that we need to dispatch an event in our framework, if we don’t programmers can’t hook into our application. Triggering events everywhere give us a small performance penalty however I do think this way of working gives the programmers a nice way to hook into your application on those spots that you want them to hook in.
Just for the record
Notice that this code is just an example and can still use some improvements, for example: each observer is initialized even it will maybe never be notified, therefore I suggest to make use of lazy in some cases for loading the objects. There are other systems to hook into an application, more to follow!
https://www.rwaq.org/users/engelhardt31iajosef-20250912095432
HarryPaync
19 Sep 25 at 9:56 pm
купить диплом в евпатории [url=http://rudik-diplom1.ru/]купить диплом в евпатории[/url] .
Diplomi_axer
19 Sep 25 at 9:56 pm
kraken сайт зеркала kraken onion, kraken onion ссылка, kraken onion зеркала, kraken рабочая ссылка onion, сайт kraken onion, kraken darknet, kraken darknet market, kraken darknet ссылка, сайт kraken darknet, kraken актуальные ссылки, кракен ссылка kraken, kraken официальные ссылки, kraken ссылка тор, kraken ссылка зеркало, kraken ссылка на сайт, kraken онион, kraken онион тор, кракен онион, кракен онион тор, кракен онион зеркало, кракен даркнет маркет, кракен darknet, кракен onion, кракен ссылка onion, кракен onion сайт, kra ссылка, kraken сайт, kraken актуальные ссылки, kraken зеркало, kraken ссылка зеркало, kraken зеркало рабочее, актуальные зеркала kraken, kraken сайт зеркала, kraken маркетплейс зеркало, кракен ссылка, кракен даркнет
RichardPep
19 Sep 25 at 9:57 pm
Cash Compass играть в 1хслотс
Eddiefen
19 Sep 25 at 9:58 pm
Way cool! Some very valid points! I appreciate you writing this
article and the rest of the site is really good.
dewascatter slot
19 Sep 25 at 9:58 pm
https://xn--krken23-bn4c.com
Howardreomo
19 Sep 25 at 10:02 pm
диплом техникума купить [url=https://www.frei-diplom12.ru]диплом техникума купить[/url] .
Diplomi_uvPt
19 Sep 25 at 10:02 pm
I was wondering if you ever thought of changing
the page layout of your website? Its very well written; I love what youve got to say.
But maybe you could a little more in the way of content so
people could connect with it better. Youve got an awful lot of text for
only having one or two pictures. Maybe you
could space it out better?
americanhistoryprojects.com lừa đảo công an truy quét cấm người chơi tham gia
19 Sep 25 at 10:04 pm
купить диплом в верхней пышме [url=https://rudik-diplom1.ru/]купить диплом в верхней пышме[/url] .
Diplomi_dqer
19 Sep 25 at 10:05 pm
Adoro de verdade o 888 Casino, parece mesmo sensacao unica de cassino. Ha uma infinidade de titulos variados, incluindo slots de ultima geracao. Os agentes estao sempre disponiveis e eficientes, oferecendo respostas rapidas e precisas. Os ganhos sao pagos em tempo recorde, as vezes os bonus poderiam ser mais frequentes. No geral, o 888 Casino oferece uma experiencia de jogo memoravel para os apaixonados por jogos digitais! Note tambem que a navegacao e simples e rapida, o que amplifica o prazer de jogar.
888 casino slot games|
Michaely7zef
19 Sep 25 at 10:06 pm
Hi mates, its enormous paragraph on the topic of
educationand completely explained, keep it up all the time.
انفجار
19 Sep 25 at 10:07 pm
диплом техникума купить цена [url=https://frei-diplom8.ru/]диплом техникума купить цена[/url] .
Diplomi_sbsr
19 Sep 25 at 10:08 pm
Ich finde absolut irre DrueGlueck Casino, es hat eine durchgeknallte Casino-Energie. Es gibt eine Flut an abwechslungsreichen Casino-Titeln, inklusive stylischer Casino-Tischspiele. Der Casino-Support ist rund um die Uhr da, antwortet in Sekundenschnelle. Casino-Transaktionen sind simpel und zuverlassig, ab und zu mehr Freispiele im Casino waren top. Am Ende ist DrueGlueck Casino ein Casino, das man nicht verpassen darf fur die, die mit Stil im Casino wetten! Extra die Casino-Plattform hat einen krassen Look, das Casino-Erlebnis total intensiviert.
drueckglueck kontakt|
moonbadger7zef
19 Sep 25 at 10:08 pm
Farmasi Nutriplus România oferă suplimente și produse de wellness care îmbină inovația,
calitatea și accesibilitatea. Descoperă o gamă variată pentru un stil de
viață sănătos, cu beneficii reale, prețuri atractive și garanția unei mărci de încredere.
Farmasi Nutriplus
19 Sep 25 at 10:08 pm
I’ve learn several excellent stuff here.
Certainly value bookmarking for revisiting. I surprise how much attempt you put to
make this sort of excellent informative site.
Margene
19 Sep 25 at 10:11 pm
купить диплом в шахтах [url=https://www.rudik-diplom8.ru]https://www.rudik-diplom8.ru[/url] .
Diplomi_nsMt
19 Sep 25 at 10:11 pm
купить диплом тренера [url=https://www.rudik-diplom11.ru]купить диплом тренера[/url] .
Diplomi_aoMi
19 Sep 25 at 10:11 pm
купить диплом логиста [url=www.rudik-diplom1.ru]купить диплом логиста[/url] .
Diplomi_izer
19 Sep 25 at 10:12 pm
Футболки полиция и рисунки на футболке печать в Якутске. Buff бейсболка и толстовка оранжевая в Казани. Логотипы на футболке и коричневые футболки в Новороссийске. Штанга для одежды настенная и упаковка спанбонд в Казани. Футболки оптом женские без надписей и футболки надпись: футболка без нанесения оптом
Gregorysnisp
19 Sep 25 at 10:13 pm
куплю диплом медсестры в москве [url=https://www.frei-diplom13.ru]куплю диплом медсестры в москве[/url] .
Diplomi_nekt
19 Sep 25 at 10:13 pm
После первичной диагностики начинается активная фаза медикаментозного вмешательства. Современные препараты вводятся капельничным методом, что позволяет быстро снизить уровень токсинов в крови, восстановить нормальный обмен веществ и стабилизировать работу внутренних органов. Этот этап играет решающую роль в безопасном выводе из запоя.
Ознакомиться с деталями – http://vyvod-iz-zapoya-donetsk-dnr00.ru/vyvod-iz-zapoya-na-domu-doneczk-dnr/
Michaelduxuh
19 Sep 25 at 10:13 pm
все онлайн займы [url=http://zaimy-17.ru]все онлайн займы[/url] .
zaimi_bmSa
19 Sep 25 at 10:14 pm
https://xn--krken21-bn4c.com
Howardreomo
19 Sep 25 at 10:14 pm
Hello there! This is my first visit to your blog!
We are a group of volunteers and starting a new
project in a community in the same niche. Your blog provided us beneficial information to work on. You have done a marvellous
job!
علائم اپی گلوتیت در کودکان
19 Sep 25 at 10:15 pm
bs2best at, bs2web at и bs2 market: глубокий анализ технологий 2025 года
bs2best at
bs2best.at blacksprut marketplace Official
CharlesNarry
19 Sep 25 at 10:15 pm
легальный диплом купить [url=https://frei-diplom4.ru/]легальный диплом купить[/url] .
Diplomi_kjOl
19 Sep 25 at 10:15 pm
купить диплом по реестру [url=http://frei-diplom5.ru]купить диплом по реестру[/url] .
Diplomi_gbPa
19 Sep 25 at 10:16 pm
https://zenless.game-chan.net/archives/1094/comment-page-236#comment-26943
Jeffreycen
19 Sep 25 at 10:18 pm
Hi there, I discovered your web site by means of Google while looking for a comparable topic, your website
came up, it appears to be like good. I’ve bookmarked it in my google
bookmarks.
Hi there, simply changed into aware of your weblog via Google, and found that it’s truly informative.
I’m going to watch out for brussels. I will
appreciate should you continue this in future. Many other folks will probably be benefited from your writing.
Cheers!
Fundspire Análise
19 Sep 25 at 10:19 pm
Adoro o role insano de Flabet Casino, da uma energia de cassino que e um espetaculo. Tem uma enxurrada de jogos de cassino irados, com caca-niqueis de cassino modernos e viciantes. A equipe do cassino entrega um atendimento que e uma joia, dando solucoes na hora e com precisao. Os pagamentos do cassino sao lisos e blindados, as vezes mais bonus regulares no cassino seria brabo. No geral, Flabet Casino garante uma diversao de cassino que e uma explosao para os amantes de cassinos online! De lambuja a interface do cassino e fluida e cheia de vibe, o que deixa cada sessao de cassino ainda mais alucinante.
de quem e a flabet|
whimsyjelly6zef
19 Sep 25 at 10:19 pm
купить диплом в муроме [url=www.rudik-diplom7.ru/]купить диплом в муроме[/url] .
Diplomi_krPl
19 Sep 25 at 10:19 pm
купить диплом цена [url=https://www.rudik-diplom10.ru]купить диплом цена[/url] .
Diplomi_spSa
19 Sep 25 at 10:19 pm
купить диплом с занесением в реестр цена [url=www.frei-diplom6.ru/]купить диплом с занесением в реестр цена[/url] .
Diplomi_viOl
19 Sep 25 at 10:19 pm
https://xn--krken21-bn4c.com
Howardreomo
19 Sep 25 at 10:19 pm
Je suis accro a Instant Casino, ca balance une vibe de jeu dementielle. Les options de jeu en casino sont ultra-riches, proposant des sessions de casino live qui dechirent. Les agents du casino sont rapides comme l’eclair, repondant en un flash. Les transactions de casino sont simples comme un neon, par contre j’aimerais plus de promos de casino qui dechirent. Bref, Instant Casino est un casino en ligne qui cartonne pour les aventuriers du casino ! A noter aussi le design du casino est une explosion visuelle, ce qui rend chaque session de casino encore plus kiffante.
instant casino site|
cosmicgecko1zef
19 Sep 25 at 10:19 pm
купить диплом с реестром вуза [url=www.frei-diplom2.ru]купить диплом с реестром вуза[/url] .
Diplomi_muEa
19 Sep 25 at 10:20 pm
Купить диплом любого университета мы поможем. Купить диплом о высшем образовании Ростов на Дону – [url=http://diplomybox.com/kupit-diplom-o-vysshem-obrazovanii-rostov-na-donu/]diplomybox.com/kupit-diplom-o-vysshem-obrazovanii-rostov-na-donu[/url]
Cazruxk
19 Sep 25 at 10:20 pm
купить диплом в реестр [url=https://frei-diplom3.ru]купить диплом в реестр[/url] .
Diplomi_ksKt
19 Sep 25 at 10:20 pm
J’apprecie enormement 1xbet Casino, ca procure une aventure pleine de frissons. Il y a une profusion de titres varies, proposant des jeux de table elegants et classiques. Les agents sont toujours disponibles et efficaces, garantissant une aide immediate. Les transactions sont parfaitement protegees, bien que j’aimerais plus d’offres promotionnelles. Pour conclure, 1xbet Casino est un incontournable pour les passionnes de jeux numeriques ! De plus la navigation est intuitive et rapide, facilite chaque session de jeu.
1xbet download 2024|
bibin6zef
19 Sep 25 at 10:21 pm
buy coke in telegram cocain in prague from dominican republic
prague-drugs-693
19 Sep 25 at 10:21 pm
диплом техникума купить [url=www.frei-diplom9.ru]диплом техникума купить[/url] .
Diplomi_nbea
19 Sep 25 at 10:21 pm
https://www.band.us/page/99959103/
HarryPaync
19 Sep 25 at 10:22 pm
best steroids to get cut
References:
1 year steroid transformation – myspace.com,
myspace.com
19 Sep 25 at 10:22 pm
https://xn--krken21-bn4c.com
Howardreomo
19 Sep 25 at 10:23 pm
Descubre Farmasi España y ordena productos cosméticos veganos de alta calidad.
Aprovecha increíbles descuentos frente al precio de catálogo oficial.
Compra maquillaje, cuidado personal y belleza natural con confianza, envío
rápido y garantía de satisfacción en Farmasi España.
Farmasi Spain
19 Sep 25 at 10:25 pm
Cool blog! Is your theme custom made or did you download it
from somewhere? A design like yours with a few simple tweeks would really make
my blog jump out. Please let me know where you got your design. Cheers
pg66.com
19 Sep 25 at 10:26 pm
С помощью инструментов, которые доступны на сайте, пользователь может увидеть границы государств, города, исторические места, религиозные центры и многое другое.
http://trivenistrainers.com/yarismalar-ve-piyangolar-internet-casinolarinda-hediyeler-ile-yueksek-hediyelerin-dagitimi/
19 Sep 25 at 10:27 pm
Когда запой становится угрозой для жизни и здоровья, своевременная помощь профессионала может стать решающим фактором для скорейшего восстановления. В Мурманске, где суровые климатические условия добавляют стресса и осложнений, квалифицированные наркологи оказывают помощь на дому, обеспечивая оперативную детоксикацию и индивидуальную терапию в привычной обстановке. Такой подход позволяет пациентам избежать лишних перемещений и получить поддержку в комфортной атмосфере.
Получить дополнительные сведения – http://vyvod-iz-zapoya-murmansk0.ru
AlfredDierb
19 Sep 25 at 10:28 pm
купить проведенный диплом о высшем образовании [url=www.frei-diplom5.ru]купить проведенный диплом о высшем образовании[/url] .
Diplomi_owPa
19 Sep 25 at 10:28 pm
высшее образование купить диплом с занесением в реестр [url=www.frei-diplom4.ru]высшее образование купить диплом с занесением в реестр[/url] .
Diplomi_eyOl
19 Sep 25 at 10:28 pm