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);
$oOrder->add();
?>
Now we are able to take action on different events that occur.
Disadvantages
Although this implementation works quite well there are some drawbacks. One of those drawbacks is that we need to dispatch an event in our framework, if we don’t programmers can’t hook into our application. Triggering events everywhere give us a small performance penalty however I do think this way of working gives the programmers a nice way to hook into your application on those spots that you want them to hook in.
Just for the record
Notice that this code is just an example and can still use some improvements, for example: each observer is initialized even it will maybe never be notified, therefore I suggest to make use of lazy in some cases for loading the objects. There are other systems to hook into an application, more to follow!
where to get cheap accutane without a prescription
generic accutane online
20 Oct 25 at 2:40 pm
1хБет код для регистрации на бонус в 2026-м — введите промокод и получите предложение в размере 100% до 100$. Данный код 1xBet позволяет заработать приветственный бонус от букмекера 1xBet при регистрации. Промокод всегда доступен по ссылке ниже — http://kitanoseeds.ru/img/pgs/?1xbet_promokod_pri_registracii_na_segodnya_besplatno.html.
Jamesslurn
20 Oct 25 at 2:42 pm
Wow, that’s what I was searching for, what a stuff!
present here at this blog, thanks admin of this site.
read more here
20 Oct 25 at 2:45 pm
купить диплом в славянске-на-кубани [url=https://rudik-diplom2.ru]https://rudik-diplom2.ru[/url] .
Diplomi_trpi
20 Oct 25 at 2:46 pm
купить диплом колледжа в москве [url=frei-diplom11.ru]frei-diplom11.ru[/url] .
Diplomi_xssa
20 Oct 25 at 2:48 pm
pferderennen mannheim wetten
Feel free to surf to my web blog: esc buchmacher deutschland
– Carolyn,
Carolyn
20 Oct 25 at 2:53 pm
[url=https://stockermobileapp.com/]The world’s first AI-driven personal stock screener[/url] redefines how traders find and evaluate stocks. This innovative platform combines artificial intelligence with human-like decision-making. You no longer need to rely solely on intuition or random tips, this smart system finds the most relevant stocks for your strategy. The more you use it, the smarter it becomes. It allows full customization to fit both beginners and experienced traders. With real-time data integration and instant analysis, the system gives you a competitive edge once reserved for hedge funds. This isn’t another stock scanner, it’s a thinking assistant. Suitable for anyone looking to improve portfolio performance, your investment strategy becomes consistent and informed. User privacy and data protection come first. Trade smarter on the go with your personal AI-powered platform. Users describe it as having a virtual financial analyst on demand. It’s designed to support your decisions, not automate them blindly. Developers refine algorithms using real trading feedback. You can uncover hidden investment opportunities in seconds. Start using your own personal AI stock screener and make smarter choices. The next generation of investing has already begun.
https://stockermobileapp.com/
StevenBoymn
20 Oct 25 at 2:54 pm
alarm clock with cd player [url=https://alarm-radio-clocks.com]https://alarm-radio-clocks.com[/url] .
Cd Player Radio Alarm Clocks_ogOa
20 Oct 25 at 2:55 pm
купить диплом в междуреченске [url=https://rudik-diplom15.ru]https://rudik-diplom15.ru[/url] .
Diplomi_wvPi
20 Oct 25 at 2:55 pm
https://odysee.com/@lifegoodneskwick73
Anthonycam
20 Oct 25 at 2:56 pm
подготовка проекта перепланировки квартиры [url=http://proekt-pereplanirovki-kvartiry11.ru]http://proekt-pereplanirovki-kvartiry11.ru[/url] .
proekt pereplanirovki kvartiri_rgot
20 Oct 25 at 2:56 pm
What’s up Dear, are you really visiting this web page regularly, if so
after that you will definitely take fastidious know-how.
Finxor GPT Avis
20 Oct 25 at 2:57 pm
best cd alarm clock radio [url=www.alarm-radio-clocks.com]www.alarm-radio-clocks.com[/url] .
Cd Player Radio Alarm Clocks_myOa
20 Oct 25 at 2:57 pm
купить диплом в омске [url=https://rudik-diplom2.ru]купить диплом в омске[/url] .
Diplomi_eipi
20 Oct 25 at 2:58 pm
Длительный запой представляет собой крайне опасное состояние, способное нанести непоправимый вред организму. При отсутствии своевременного вмешательства алкогольная интоксикация может привести к серьезным осложнениям, таким как нарушение работы сердца, печени, почек и нервной системы, а также развитию алкогольного психоза. В таких ситуациях экстренная медицинская помощь является залогом спасения жизни и предотвращения необратимых последствий. Клиника «ЗдоровьеНорм» предлагает круглосуточный выезд специалистов для вывода из запоя на дому в Краснодаре и по всему Краснодарскому краю. Наши врачи работают 24 часа в сутки, обеспечивая полный комплекс процедур по детоксикации, снятию абстинентного синдрома и восстановлению организма, при этом гарантируя полную анонимность и индивидуальный подход к каждому пациенту.
Изучить вопрос глубже – [url=https://narcolog-na-dom-krasnodar0.ru/]нарколог на дом срочно краснодар[/url]
WalterHof
20 Oct 25 at 2:58 pm
It’s actually very difficult in this busy life to listen news on Television, therefore I simply use web for that purpose, and get the newest news.
with local private key creation and offline capabilities to keep your data safe. Compatible with TRON’s ecosystem
20 Oct 25 at 2:59 pm
online connect
MichaelSig
20 Oct 25 at 3:01 pm
pin-up [url=https://pinup5008.ru/]https://pinup5008.ru/[/url]
pin_up_uz_axSt
20 Oct 25 at 3:04 pm
диплом техникума купить с проводкой [url=http://frei-diplom11.ru]диплом техникума купить с проводкой[/url] .
Diplomi_eosa
20 Oct 25 at 3:05 pm
Алкогольная зависимость — сложное хроническое заболевание, требующее комплексного подхода и квалифицированной помощи. В клинике «Тюменьбезалко» в центре Тюмени разработаны эффективные программы реабилитации, сочетающие современные медицинские методы, психологическую поддержку и социальную адаптацию. Опытные врачи-наркологи и психотерапевты помогают пациентам преодолеть употребление алкоголя, восстановить физическое и эмоциональное здоровье и вернуться к полноценной жизни.
Детальнее – http://lechenie-alkogolizma-tyumen10.ru
Devinpag
20 Oct 25 at 3:05 pm
В условиях современного ритма жизни алкоголизм нередко оборачивается тяжёлыми последствиями — от кратковременных запоев до хронической зависимости с серьёзными осложнениями. Наркологическая клиника «ТюменьМед» предлагает круглосуточную поддержку и выезд специалистов на дом в любое время суток, обеспечивая быстрое и безопасное восстановление здоровья. Использование инновационных методик, мобильных лабораторий и дистанционного контроля позволяет пациентам пройти детоксикацию и начать новый этап жизни в комфортных для них условиях.
Получить дополнительные сведения – https://narkologicheskaya-klinika-tyumen10.ru/
WilliamFeece
20 Oct 25 at 3:06 pm
Excellent blog here! Also your website loads up fast!
What host are you using? Can I get your affiliate link to
your host? I wish my website loaded up as fast as yours lol
m98 ทางเข้า
20 Oct 25 at 3:08 pm
Joined $MTAUR rush—prizes await. ICO’s tokenomics sound. Mazes challenging.
mtaur coin
WilliamPargy
20 Oct 25 at 3:09 pm
I always spent my half an hour to read this webpage’s posts daily along with a mug of coffee.
Adam & Eve bondage
20 Oct 25 at 3:11 pm
MELBET-лучшие коэффиценты
Лучший букмекер,со своей историей поможет вам заработать целое состояние.
Присоединяйтесь к нам ,пополняйте счет на любую сумму и забирайте свой бонус с [url=https://melbetkz.lol]MELBET[/url]
Artemstylew
20 Oct 25 at 3:11 pm
clock radio alarm clock cd [url=https://alarm-radio-clocks.com/]alarm-radio-clocks.com[/url] .
Cd Player Radio Alarm Clocks_ljOa
20 Oct 25 at 3:11 pm
Normally I don’t learn post on blogs, however I would like
to say that this write-up very forced me to try and do it! Your writing taste has been surprised me.
Thanks, very great post.
시알리스 구매
20 Oct 25 at 3:12 pm
Что думаете, стоит ли заказывать у https://trksfera.ru
? Цены нормальные, доставка работает. Но хочется узнать про фактическое качество.
Stevenref
20 Oct 25 at 3:13 pm
перепланировка квартиры дизайн проект [url=https://proekt-pereplanirovki-kvartiry11.ru]перепланировка квартиры дизайн проект[/url] .
proekt pereplanirovki kvartiri_riot
20 Oct 25 at 3:17 pm
пин ап восстановить пароль [url=http://pinup5007.ru]пин ап восстановить пароль[/url]
pin_up_uz_yqsr
20 Oct 25 at 3:18 pm
«Капельница от запоя» в современном понимании — это не одна универсальная смесь, а последовательность управляемых шагов с понятной целью, измеримыми показателями и заранее назначенными точками переоценки. В наркологической клинике «СеверАльфа Мед» мы используем модульные инфузионные протоколы и бережный мониторинг, чтобы безопасно снять интоксикацию, восстановить водно-электролитный баланс, снизить тремор и вернуть физиологичный сон без «переседации». Каждый этап сопровождается сервисом конфиденциального уровня: нейтральные формулировки в документах, немаркированная логистика, «тихие» каналы связи, доступ к записям строго по ролям. Это делает путь пациента предсказуемым и защищённым от лишнего внимания.
Изучить вопрос глубже – [url=https://kapelnicza-ot-zapoya-murmansk15.ru/]капельница от запоя анонимно в мурманске[/url]
WilliamMayox
20 Oct 25 at 3:21 pm
купить диплом специалиста [url=www.rudik-diplom14.ru/]купить диплом специалиста[/url] .
Diplomi_euea
20 Oct 25 at 3:22 pm
пин ап apk скачать [url=https://www.pinup5007.ru]https://www.pinup5007.ru[/url]
pin_up_uz_aksr
20 Oct 25 at 3:24 pm
диплом юридического колледжа купить [url=www.frei-diplom11.ru/]www.frei-diplom11.ru/[/url] .
Diplomi_vjsa
20 Oct 25 at 3:24 pm
Квартира с отделкой https://новостройкивспб.рф экономия времени и предсказуемый бюджет. Фильтруем по планировкам, материалам, классу дома и акустике. Проверяем стандарт отделки, толщину стяжки, ровность стен, работу дверей/окон, скрытые коммуникации. Приёмка по дефект-листу, штрафы за просрочку.
ShawnTut
20 Oct 25 at 3:26 pm
купить диплом в орле [url=https://www.rudik-diplom2.ru]https://www.rudik-diplom2.ru[/url] .
Diplomi_pnpi
20 Oct 25 at 3:29 pm
купить диплом в славянске-на-кубани [url=http://rudik-diplom15.ru/]http://rudik-diplom15.ru/[/url] .
Diplomi_xyPi
20 Oct 25 at 3:30 pm
пин ап как зарегистрироваться [url=http://pinup5008.ru/]http://pinup5008.ru/[/url]
pin_up_uz_ijSt
20 Oct 25 at 3:33 pm
кракен
кракен маркет
JamesDaync
20 Oct 25 at 3:34 pm
проект перепланировки квартиры в москве [url=http://proekt-pereplanirovki-kvartiry11.ru]http://proekt-pereplanirovki-kvartiry11.ru[/url] .
proekt pereplanirovki kvartiri_ofot
20 Oct 25 at 3:35 pm
Excited for $MTAUR coin’s role in personalizing characters—fancy outfits via tokens? Yes please. Presale’s low barrier ($10 min) opens it to everyone. Community events sound epic.
minotaurus token
WilliamPargy
20 Oct 25 at 3:37 pm
Квартира с отделкой https://новостройкивспб.рф экономия времени и предсказуемый бюджет. Фильтруем по планировкам, материалам, классу дома и акустике. Проверяем стандарт отделки, толщину стяжки, ровность стен, работу дверей/окон, скрытые коммуникации. Приёмка по дефект-листу, штрафы за просрочку.
ShawnTut
20 Oct 25 at 3:38 pm
купить диплом маркетолога [url=https://rudik-diplom14.ru]купить диплом маркетолога[/url] .
Diplomi_vqea
20 Oct 25 at 3:38 pm
I don’t even know the way I ended up here, but I thought this publish used to be
good. I do not know who you’re however certainly you’re
going to a well-known blogger for those who are not already.
Cheers!
cleaning service Port Moody
20 Oct 25 at 3:40 pm
The Supreme Court agreed Monday to decide if the federal government may bar certain drug users from owning guns or if the law violates the Second Amendment, taking up a second significant guns case of its current term.
[url=https://kra42cc.net]kra42 сс[/url]
The appeal represents a rare circumstance in which the Trump administration is defending a gun prohibition, which it described in briefing at the Supreme Court as a “narrow” limitation on one of “Americans’ most cherished freedoms.”
[url=https://kra-42—cc.ru]kra42 сс[/url]
The case centers on Ali Danial Hemani, a dual citizen of the United States and Pakistan, who was indicted in 2023 on a single count of violating the guns-and-drugs law after the FBI found a 9mm pistol, 60 grams of marijuana, and 4.7 grams of cocaine at his family home. This prosecution, the government told the high court, rested Hemani’s habitual use of marijuana.
The court will likely hear arguments in the Hemani case next year and hand down a decision by the end of June.
kra42 сс
https://kra42-cc.net
A federal district court dismissed the charge, noting a landmark decision from the Supreme Court in 2022 that made it easier for Americans to carry handguns in public and also required similar gun prohibitions to have a connection to history.
But just how closely analogous prosecutors must come to a historic law has been a matter of debate. Last year, for instance, the Supreme Court upheld a federal law that bars guns for Americans who are the subject of certain domestic abuse restraining orders, rejecting an argument pressed by gun rights groups that the prohibition violated the Second Amendment.
The conservative 5th US Circuit Court of Appeals upheld that decision, holding in a brief decision that the historical record points only to laws that barred guns for Americans who are actively intoxicated or under the influence of drugs at the time of their arrest. The government, the court ruled, could not target habitual users.
The Trump administration appealed that decision.
CoreyBib
20 Oct 25 at 3:41 pm
pin up virtual sport tikish [url=https://www.pinup5007.ru]pin up virtual sport tikish[/url]
pin_up_uz_znsr
20 Oct 25 at 3:41 pm
Квартира с отделкой https://новостройкивспб.рф экономия времени и предсказуемый бюджет. Фильтруем по планировкам, материалам, классу дома и акустике. Проверяем стандарт отделки, толщину стяжки, ровность стен, работу дверей/окон, скрытые коммуникации. Приёмка по дефект-листу, штрафы за просрочку.
ShawnTut
20 Oct 25 at 3:42 pm
pin up uz ro‘yxatdan o‘tish [url=https://www.pinup5007.ru]https://www.pinup5007.ru[/url]
pin_up_uz_jjsr
20 Oct 25 at 3:42 pm
Hi there! I could have sworn I’ve been to this website before
but after browsing through a few of the posts I realized it’s new to me.
Nonetheless, I’m definitely happy I discovered it and I’ll be book-marking
it and checking back frequently!
https://google-chrome.ru.com/
20 Oct 25 at 3:43 pm
купить диплом монтажника [url=https://rudik-diplom15.ru]купить диплом монтажника[/url] .
Diplomi_ymPi
20 Oct 25 at 3:44 pm