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!
Мы применяем модульный подход: медицинские и психологические интервенции настраиваются как «кубики», а последовательность их включения зависит от состояния пациента. Схема гибко масштабируется — от краткого курса стабилизации до расширенной реабилитации с семейной поддержкой. Ниже — каркас маршрута, которым мы руководствуемся чаще всего.
Узнать больше – [url=https://narcologicheskaya-klinika-stavropol0.ru/]запой наркологическая клиника[/url]
RonaldEralf
24 Oct 25 at 11:13 pm
Hi there! I know this is kinda off topic but I was wondering if you knew where I could find a captcha plugin for my comment form?
I’m using the same blog platform as yours and I’m having difficulty finding one?
Thanks a lot!
slot gacor 777
24 Oct 25 at 11:14 pm
На первом контакте координатор задаёт несколько точных вопросов: длительность эпизода, наличие рвоты/тремора/бессонницы, приём лекарств, хронические заболевания. Эти данные нужны не «для галочки»: по ним заранее выстраивается протокол инфузии, рассчитывается скорость, подбираются уколы до капельницы и объём наблюдения после. Врач приезжает уже с персональным планом и поправляет его по факту осмотра.
Получить больше информации – [url=https://vyvod-iz-zapoya-petrozavodsk0.ru/]вывод из запоя клиника петрозаводск[/url]
PatrickSlode
24 Oct 25 at 11:16 pm
1xbet tr giri? [url=www.1xbet-7.com/]www.1xbet-7.com/[/url] .
1xbet_faol
24 Oct 25 at 11:19 pm
News.biz.ua — динамичная лента Украины с фокусом на бизнес, экономику, технологии и транспорт, дополненная оперативными сводками и спортом. Портал сочетает короткие новости и тематические разборы, чтобы быстро понять, что влияет на рынки и повседневность. Удобные рубрики, курсы валют и аккуратная верстка помогают читать с любого устройства. Откройте https://news.biz.ua/ — держите руку на пульсе решений Кабмина, корпоративных трендов и историй, которые меняют повестку дня.
liciwthsob
24 Oct 25 at 11:20 pm
диплом техникума купить в украине [url=http://www.frei-diplom12.ru]диплом техникума купить в украине[/url] .
Diplomi_ooPt
24 Oct 25 at 11:21 pm
купить проведенный диплом вуза [url=https://www.frei-diplom1.ru]https://www.frei-diplom1.ru[/url] .
Diplomi_ojOi
24 Oct 25 at 11:21 pm
купить диплом в чайковском [url=https://rudik-diplom13.ru]купить диплом в чайковском[/url] .
Diplomi_mhon
24 Oct 25 at 11:21 pm
1xbetgiri? [url=www.1xbet-7.com/]www.1xbet-7.com/[/url] .
1xbet_pzol
24 Oct 25 at 11:22 pm
https://t.me/s/bs_1xbet/13
https://t.me/bs_1xbet/39
24 Oct 25 at 11:24 pm
1x bet [url=www.1xbet-9.com/]www.1xbet-9.com/[/url] .
1xbet_xaSn
24 Oct 25 at 11:25 pm
https://t.me/bs_1xbet/2
https://t.me/s/bs_1xbet/41
24 Oct 25 at 11:25 pm
1xbet [url=https://www.1xbet-4.com]https://www.1xbet-4.com[/url] .
1xbet_idol
24 Oct 25 at 11:26 pm
купить диплом ташкентского техникума [url=www.frei-diplom12.ru]купить диплом ташкентского техникума[/url] .
Diplomi_njPt
24 Oct 25 at 11:27 pm
купить диплом с занесением в реестр цена [url=www.frei-diplom1.ru]купить диплом с занесением в реестр цена[/url] .
Diplomi_tjOi
24 Oct 25 at 11:27 pm
как можно купить диплом колледжа [url=http://frei-diplom11.ru]http://frei-diplom11.ru[/url] .
Diplomi_umsa
24 Oct 25 at 11:30 pm
The directives largely roll back efforts made over the last decade attempting to eradicate toxic culture in the military, both to decrease harmful behaviors like harassment, but also to meet practical needs of getting people in uniform and keeping them there longer as the military branches faced years of struggles filling the ranks.
[url=https://ckmosstroy.ru/kra43-at]kra40 at[/url]
Many major reforms were described by the officials who implemented them as driven by that need; when former Defense Secretary Ash Carter opened up combat roles to women in 2015, he said the military “cannot afford to cut ourselves off from half the country’s talents and skills” if it wanted to succeed in national defense.
[url=https://kra–43-cc.ru/kra42.cc]kra42 at[/url]
And while the military had made changes in recent years in an attempt to lessen instances of harassment, discrimination or toxic leadership by creating reporting mechanisms so that troops would come forward, Hegseth said those efforts went too far and were undercutting commanders.
“The definition of ‘toxic’ has been turned upside down, and we’re correcting that,” Hegseth vowed on Tuesday, adding that the Defense Department would be undertaking a review of words like “hazing” and “bullying” which he said had been “weaponized.”
kra49 cc
https://kra-42.ru/kra40cc
ClydeBlomo
24 Oct 25 at 11:30 pm
https://t.me/bs_1xbet/18
https://t.me/bs_1xbet/10
24 Oct 25 at 11:31 pm
Уже при первичном звонке мы собираем ключевую информацию: длительность употребления, типы веществ, сопутствующие заболевания, прошлые реакции на лекарства, эпизоды судорог и психозов, недавние значения АД/ЧСС. Это позволяет подготовить персональный стартовый протокол ещё до визита: поставить цель на первые 72 часа, определить метрики (сон, «тяга», дневная энергия), запланировать вечерний ритуал и расписать дистанционные чек-ины. Прозрачность шагов снижает тревогу у пациента и семьи и повышает соблюдаемость — фундамент устойчивого результата.
Ознакомиться с деталями – [url=https://narkologicheskaya-klinika-kamensk-uralskij0.ru/]частная наркологическая клиника[/url]
Brandonrig
24 Oct 25 at 11:31 pm
1xbet turkey [url=www.1xbet-7.com/]www.1xbet-7.com/[/url] .
1xbet_ebol
24 Oct 25 at 11:31 pm
https://t.me/s/bs_1xbet/16
https://t.me/bs_1xbet/17
24 Oct 25 at 11:31 pm
купить диплом хореографа [url=http://www.rudik-diplom13.ru]купить диплом хореографа[/url] .
Diplomi_kion
24 Oct 25 at 11:32 pm
диплом мед колледжа купить [url=www.frei-diplom12.ru]www.frei-diplom12.ru[/url] .
Diplomi_afPt
24 Oct 25 at 11:32 pm
If you are going for best contents like I do, just go to see this web page daily because it presents quality contents,
thanks
teslabahis yeni giriş
24 Oct 25 at 11:33 pm
купить диплом института с реестром [url=frei-diplom1.ru]купить диплом института с реестром[/url] .
Diplomi_svOi
24 Oct 25 at 11:35 pm
1xbet tr giri? [url=https://1xbet-7.com/]https://1xbet-7.com/[/url] .
1xbet_pmol
24 Oct 25 at 11:38 pm
The Oktoberfest beer festival in Munich will remain shut on Wednesday until at least 5 pm (1500 GMT) after police said they discovered explosives in a residential building in the north of the city that caught fire and left one person dead.
[url=https://kra38с-cc.ru]kra38 сс[/url]
As part of a major operation that police earlier said posed no danger to the public, special forces were investigating an area in the north of Munich where Bild newspaper and multiple other reports said shots and explosions had been heard.
[url=https://at-kra41cc.ru]kra41 сс[/url]
Police said the residential building had been deliberately set on fire in a family dispute and one person who was found there had died and another was missing, but not believed to be in danger.
[url=https://kra39сc-c.ru]kra38 at[/url]
Special forces had to be brought in to defuse booby traps found in the building, according to police.
“We are currently investigating all possibilities. Possible connections to other locations in Munich are being examined, including the Theresienwiese (where the Oktoberfest is located),” said Munich police on the WhatsApp messaging service.
“For this reason, the opening of the festival grounds has been delayed,” police added.
kra39 сс
https://at-kra40cc.ru
Rodneynen
24 Oct 25 at 11:38 pm
купить диплом в кстово [url=https://rudik-diplom6.ru/]https://rudik-diplom6.ru/[/url] .
Diplomi_akKr
24 Oct 25 at 11:38 pm
The scale of these recent attacks means Ukraine needs any help it can get to minimize the impacts – and volunteers are playing an increasingly important role in the defensive mix.
[url=https://kra48.at-kra48.cc ]kra47[/url]
Civilians are forming units tasked with shooting down smaller drones with machine guns or, most recently, specially developed interceptor drones.
[url=https://kra41cc.net ]kra47 cc[/url]
The chief of staff of one of Kyiv’s volunteer formation legions, Andriy, whose call-sign is Stolyar, said his unit is composed of people from all walks of life – from construction workers to businessmen to poets.
He told CNN the training for his legion lasts for about six weeks and includes basic knowledge, simulator practice and topography lessons. Andriy asked for his last name not to be published for security reasons.
“A person must understand how to operate an aircraft. Drones are becoming increasingly complex – this is aviation, and it requires constant attention, knowledge, and skills,” he said.
kra46
https://kra47at.com
Edwardheicy
24 Oct 25 at 11:40 pm
Ежедневная уборка квартир и дома необходима тем людям, у которых нет возможности самостоятельно регулярно поддерживать чистоту в
помещении.
клининг от Uberu24
24 Oct 25 at 11:41 pm
Yes! Finally someone writes about Noble Fundrelix.
Noble Fundrelix Legit Or Not
24 Oct 25 at 11:42 pm
1xbet [url=www.1xbet-9.com]1xbet[/url] .
1xbet_wuSn
24 Oct 25 at 11:43 pm
one x bet [url=www.1xbet-4.com]www.1xbet-4.com[/url] .
1xbet_vmol
24 Oct 25 at 11:46 pm
Hi there great website! Does running a blog such as this require a large
amount of work? I’ve very little expertise in programming however I
had been hoping to start my own blog soon. Anyhow, if you have any recommendations or tips for new
blog owners please share. I understand this is off topic but I simply needed to ask.
Many thanks!
Auto accident lawyer
24 Oct 25 at 11:47 pm
купить диплом в нижнем тагиле [url=http://rudik-diplom2.ru]купить диплом в нижнем тагиле[/url] .
Diplomi_ispi
24 Oct 25 at 11:47 pm
купить диплом в серове [url=http://rudik-diplom13.ru/]купить диплом в серове[/url] .
Diplomi_nfon
24 Oct 25 at 11:48 pm
Hi there very nice web site!! Guy .. Beautiful ..
Superb .. I will bookmark your site and take the feeds additionally?
I’m glad to find a lot of useful info right here in the put up, we want work out more techniques in this regard, thank
you for sharing. . . . . .
Live Draw Sdy
24 Oct 25 at 11:48 pm
You can definitely see your skills in the article you write.
The arena hopes for more passionate writers such as you who
are not afraid to mention how they believe. Always follow your heart.
Live Draw Hk
24 Oct 25 at 11:50 pm
казахстан купить диплом техникума [url=frei-diplom11.ru]казахстан купить диплом техникума[/url] .
Diplomi_pesa
24 Oct 25 at 11:52 pm
1xbet giri? adresi [url=www.1xbet-7.com/]www.1xbet-7.com/[/url] .
1xbet_cwol
24 Oct 25 at 11:52 pm
https://t.me/bs_1xbet/16
https://t.me/s/bs_1xbet/37
24 Oct 25 at 11:54 pm
https://t.me/bs_1xbet/8
https://t.me/bs_1xbet/5
24 Oct 25 at 11:55 pm
В клинике «ЮгМед Альянс» выстроена система непрерывного медицинского наблюдения. При поступлении проводится комплексная диагностика, назначается детоксикация и поддерживающая терапия, затем начинается стабилизация физического и эмоционального состояния. Благодаря круглосуточной работе бригад и возможности экстренного выезда на дом пациенты получают помощь без задержек. Конфиденциальность соблюдается на всех уровнях — от первичного звонка до выписки. Для удобства родственников организована система информирования: короткие апдейты по согласованным каналам связи и только в определённое время, чтобы не нарушать покой пациента.
Подробнее – [url=https://narkologicheskaya-klinika-stavropol0.ru/]наркологическая клиника стационар в ставрополе[/url]
JerrodFef
24 Oct 25 at 11:55 pm
1xbet resmi [url=https://1xbet-9.com/]1xbet-9.com[/url] .
1xbet_yaSn
24 Oct 25 at 11:57 pm
купить диплом в вольске [url=rudik-diplom6.ru]rudik-diplom6.ru[/url] .
Diplomi_xsKr
24 Oct 25 at 11:57 pm
birxbet [url=1xbet-7.com]1xbet-7.com[/url] .
1xbet_leol
24 Oct 25 at 11:58 pm
1xbet guncel [url=https://1xbet-4.com]https://1xbet-4.com[/url] .
1xbet_dzol
25 Oct 25 at 12:00 am
Oh no, primary maths teaches everyday սses including financial planning, so guarantee yоur child ցets it
correctly starting y᧐ung age.
Hey hey, composed pom pi pi, maths іs amօng of the leading
subjects ɗuring Junior College, establishing groundwork tⲟ Α-Level
advanced math.
Anderson Serangoon Junior College іs ɑ vibrant organization born from tһе merger օf tᴡо esteemed colleges, promoting аn encouraging environment tһat emphasizes holistic development ɑnd
scholastic quality. Ꭲhе college boasts modern-ԁay facilities, including innovative laboratories аnd collaborative spaces, allowing
trainees tо engage deeply іn STEM and innovation-driven projects.
Ԝith а strong focus оn leadership аnd character building, students gain fгom varied
cо-curricular activities thаt cultivate strength аnd
team effort. Its dedication to international perspectives tһrough exchange programs expands
horizons ɑnd prepares students for an interconnected ᴡorld.
Graduates typically safe ɑnd secure places
in leading universities, reflecting tһe college’s devotion tⲟ supporting positive, ᴡell-rounded people.
Millennia Institute stands аpart witһ itѕ distinctive three-year pre-university pathway гesulting іn tһе
GCE A-Level assessments, providing flexible аnd in-depth study alternatives іn commerce,
arts, and sciences tailored to accommodate а diverse variety ⲟf learners and
their special goals. As ɑ central institute, it useѕ customnized assistance ɑnd support ɡroup, consisting of devoted scholastic
advisors аnd counseling services, tⲟ guarantee every student’ѕ holistic advancement and scholastic success іn a inspiring environment.
Tһe institute’s cuttiong edge centers, ѕuch aѕ digital knowing centers, multimedia resource centers, аnd collective workspaces, produce аn
interesting platform f᧐r ingenious mentor methods аnd hands-on tasks that bridge theory
ᴡith practical application. Тhrough strong market partnerships, students accss
real-ѡorld experiences ⅼike internships, workshops with specialists,
аnd scholarship chances tһat enhance tһeir employability and profession preparedness.
Alumni fｒom Millennia Institute regularly achieve success іn college and professional arenas,
ѕhowing the institution’ѕ unwavering dedication tߋ promoting lifelong
learning, flexibility, ɑnd individual empowerment.
Wow, math іs tһe groundwork block fоr primary education, assisting youngsters ᴡith
dimensional analysis fοr design paths.
Hey hey, Singapore parents, maths іs ⅼikely the highly essential
primary subject, encouraging imagination іn prⲟblem-solving
tⲟ groundbreaking careers.
Hey hey, Singapore parents, maths іs perhaps the highly important primary discipline, promoting innovation tһrough ρroblem-solving
to innovative professions.
Ꮤithout solid Ꭺ-levels,alternative paths aree ⅼonger ɑnd
harder.
Ɗοn’t mess around lah, link ɑ excellent Junior College alongside maths superiority tߋ assure
elevated Α Levels scores plus effortless shifts.
Αlso visit mү web ρage … student tutor nus math
student tutor nus math
25 Oct 25 at 12:00 am
https://t.me/bs_1xbet/19
https://t.me/bs_1xbet/15
25 Oct 25 at 12:01 am
купить аттестат за классов [url=http://www.rudik-diplom14.ru]купить аттестат за классов[/url] .
Diplomi_ylea
25 Oct 25 at 12:01 am