<?php
namespace Illuminate\Events;
use Exception;
use Illuminate\Container\Container;
use Illuminate\Contracts\Broadcasting\Factory as BroadcastFactory;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Contracts\Container\Container as ContainerContract;
use Illuminate\Contracts\Events\Dispatcher as DispatcherContract;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Support\Arr;
use Illuminate\Support\Str;
use ReflectionClass;
class Dispatcher implements DispatcherContract
{
/**
* The IoC container instance.
*
* @var \Illuminate\Contracts\Container\Container
*/
protected $container;
/**
* The registered event listeners.
*
* @var array
*/
protected $listeners = [];
/**
* The wildcard listeners.
*
* @var array
*/
protected $wildcards = [];
/**
* The cached wildcard listeners.
*
* @var array
*/
protected $wildcardsCache = [];
/**
* The queue resolver instance.
*
* @var callable
*/
protected $queueResolver;
/**
* Create a new event dispatcher instance.
*
* @param \Illuminate\Contracts\Container\Container|null $container
* @return void
*/
public function __construct(ContainerContract $container = null)
{
$this->container = $container ?: new Container;
}
/**
* Register an event listener with the dispatcher.
*
* @param string|array $events
* @param mixed $listener
* @return void
*/
public function listen($events, $listener)
{
foreach ((array) $events as $event) {
if (Str::contains($event, '*')) {
$this->setupWildcardListen($event, $listener);
} else {
$this->listeners[$event][] = $this->makeListener($listener);
}
}
}
/**
* Setup a wildcard listener callback.
*
* @param string $event
* @param mixed $listener
* @return void
*/
protected function setupWildcardListen($event, $listener)
{
$this->wildcards[$event][] = $this->makeListener($listener, true);
$this->wildcardsCache = [];
}
/**
* Determine if a given event has listeners.
*
* @param string $eventName
* @return bool
*/
public function hasListeners($eventName)
{
return isset($this->listeners[$eventName]) || isset($this->wildcards[$eventName]);
}
/**
* Register an event and payload to be fired later.
*
* @param string $event
* @param array $payload
* @return void
*/
public function push($event, $payload = [])
{
$this->listen($event.'_pushed', function () use ($event, $payload) {
$this->dispatch($event, $payload);
});
}
/**
* Flush a set of pushed events.
*
* @param string $event
* @return void
*/
public function flush($event)
{
$this->dispatch($event.'_pushed');
}
/**
* Register an event subscriber with the dispatcher.
*
* @param object|string $subscriber
* @return void
*/
public function subscribe($subscriber)
{
$subscriber = $this->resolveSubscriber($subscriber);
$subscriber->subscribe($this);
}
/**
* Resolve the subscriber instance.
*
* @param object|string $subscriber
* @return mixed
*/
protected function resolveSubscriber($subscriber)
{
if (is_string($subscriber)) {
return $this->container->make($subscriber);
}
return $subscriber;
}
/**
* Fire an event until the first non-null response is returned.
*
* @param string|object $event
* @param mixed $payload
* @return array|null
*/
public function until($event, $payload = [])
{
return $this->dispatch($event, $payload, true);
}
/**
* Fire an event and call the listeners.
*
* @param string|object $event
* @param mixed $payload
* @param bool $halt
* @return array|null
*/
public function dispatch($event, $payload = [], $halt = false)
{
// When the given "event" is actually an object we will assume it is an event
// object and use the class as the event name and this event itself as the
// payload to the handler, which makes object based events quite simple.
[$event, $payload] = $this->parseEventAndPayload(
$event, $payload
);
if ($this->shouldBroadcast($payload)) {
$this->broadcastEvent($payload[0]);
}
$responses = [];
foreach ($this->getListeners($event) as $listener) {
$response = $listener($event, $payload);
// If a response is returned from the listener and event halting is enabled
// we will just return this response, and not call the rest of the event
// listeners. Otherwise we will add the response on the response list.
if ($halt && ! is_null($response)) {
return $response;
}
// If a boolean false is returned from a listener, we will stop propagating
// the event to any further listeners down in the chain, else we keep on
// looping through the listeners and firing every one in our sequence.
if ($response === false) {
break;
}
$responses[] = $response;
}
return $halt ? null : $responses;
}
/**
* Parse the given event and payload and prepare them for dispatching.
*
* @param mixed $event
* @param mixed $payload
* @return array
*/
protected function parseEventAndPayload($event, $payload)
{
if (is_object($event)) {
[$payload, $event] = [[$event], get_class($event)];
}
return [$event, Arr::wrap($payload)];
}
/**
* Determine if the payload has a broadcastable event.
*
* @param array $payload
* @return bool
*/
protected function shouldBroadcast(array $payload)
{
return isset($payload[0]) &&
$payload[0] instanceof ShouldBroadcast &&
$this->broadcastWhen($payload[0]);
}
/**
* Check if event should be broadcasted by condition.
*
* @param mixed $event
* @return bool
*/
protected function broadcastWhen($event)
{
return method_exists($event, 'broadcastWhen')
? $event->broadcastWhen() : true;
}
/**
* Broadcast the given event class.
*
* @param \Illuminate\Contracts\Broadcasting\ShouldBroadcast $event
* @return void
*/
protected function broadcastEvent($event)
{
$this->container->make(BroadcastFactory::class)->queue($event);
}
/**
* Get all of the listeners for a given event name.
*
* @param string $eventName
* @return array
*/
public function getListeners($eventName)
{
$listeners = $this->listeners[$eventName] ?? [];
$listeners = array_merge(
$listeners,
$this->wildcardsCache[$eventName] ?? $this->getWildcardListeners($eventName)
);
return class_exists($eventName, false)
? $this->addInterfaceListeners($eventName, $listeners)
: $listeners;
}
/**
* Get the wildcard listeners for the event.
*
* @param string $eventName
* @return array
*/
protected function getWildcardListeners($eventName)
{
$wildcards = [];
foreach ($this->wildcards as $key => $listeners) {
if (Str::is($key, $eventName)) {
$wildcards = array_merge($wildcards, $listeners);
}
}
return $this->wildcardsCache[$eventName] = $wildcards;
}
/**
* Add the listeners for the event's interfaces to the given array.
*
* @param string $eventName
* @param array $listeners
* @return array
*/
protected function addInterfaceListeners($eventName, array $listeners = [])
{
foreach (class_implements($eventName) as $interface) {
if (isset($this->listeners[$interface])) {
foreach ($this->listeners[$interface] as $names) {
$listeners = array_merge($listeners, (array) $names);
}
}
}
return $listeners;
}
/**
* Register an event listener with the dispatcher.
*
* @param \Closure|string $listener
* @param bool $wildcard
* @return \Closure
*/
public function makeListener($listener, $wildcard = false)
{
if (is_string($listener)) {
return $this->createClassListener($listener, $wildcard);
}
return function ($event, $payload) use ($listener, $wildcard) {
if ($wildcard) {
return $listener($event, $payload);
}
return $listener(...array_values($payload));
};
}
/**
* Create a class based listener using the IoC container.
*
* @param string $listener
* @param bool $wildcard
* @return \Closure
*/
public function createClassListener($listener, $wildcard = false)
{
return function ($event, $payload) use ($listener, $wildcard) {
if ($wildcard) {
return call_user_func($this->createClassCallable($listener), $event, $payload);
}
return call_user_func_array(
$this->createClassCallable($listener), $payload
);
};
}
/**
* Create the class based event callable.
*
* @param string $listener
* @return callable
*/
protected function createClassCallable($listener)
{
[$class, $method] = $this->parseClassCallable($listener);
if ($this->handlerShouldBeQueued($class)) {
return $this->createQueuedHandlerCallable($class, $method);
}
return [$this->container->make($class), $method];
}
/**
* Parse the class listener into class and method.
*
* @param string $listener
* @return array
*/
protected function parseClassCallable($listener)
{
return Str::parseCallback($listener, 'handle');
}
/**
* Determine if the event handler class should be queued.
*
* @param string $class
* @return bool
*/
protected function handlerShouldBeQueued($class)
{
try {
return (new ReflectionClass($class))->implementsInterface(
ShouldQueue::class
);
} catch (Exception $e) {
return false;
}
}
/**
* Create a callable for putting an event handler on the queue.
*
* @param string $class
* @param string $method
* @return \Closure
*/
protected function createQueuedHandlerCallable($class, $method)
{
return function () use ($class, $method) {
$arguments = array_map(function ($a) {
return is_object($a) ? clone $a : $a;
}, func_get_args());
if ($this->handlerWantsToBeQueued($class, $arguments)) {
$this->queueHandler($class, $method, $arguments);
}
};
}
/**
* Determine if the event handler wants to be queued.
*
* @param string $class
* @param array $arguments
* @return bool
*/
protected function handlerWantsToBeQueued($class, $arguments)
{
$instance = $this->container->make($class);
if (method_exists($instance, 'shouldQueue')) {
return $instance->shouldQueue($arguments[0]);
}
return true;
}
/**
* Queue the handler class.
*
* @param string $class
* @param string $method
* @param array $arguments
* @return void
*/
protected function queueHandler($class, $method, $arguments)
{
[$listener, $job] = $this->createListenerAndJob($class, $method, $arguments);
$connection = $this->resolveQueue()->connection(
$listener->connection ?? null
);
$queue = $listener->queue ?? null;
isset($listener->delay)
? $connection->laterOn($queue, $listener->delay, $job)
: $connection->pushOn($queue, $job);
}
/**
* Create the listener and job for a queued listener.
*
* @param string $class
* @param string $method
* @param array $arguments
* @return array
*/
protected function createListenerAndJob($class, $method, $arguments)
{
$listener = (new ReflectionClass($class))->newInstanceWithoutConstructor();
return [$listener, $this->propagateListenerOptions(
$listener, new CallQueuedListener($class, $method, $arguments)
)];
}
/**
* Propagate listener options to the job.
*
* @param mixed $listener
* @param mixed $job
* @return mixed
*/
protected function propagateListenerOptions($listener, $job)
{
return tap($job, function ($job) use ($listener) {
$job->tries = $listener->tries ?? null;
$job->retryAfter = $listener->retryAfter ?? null;
$job->timeout = $listener->timeout ?? null;
$job->timeoutAt = method_exists($listener, 'retryUntil')
? $listener->retryUntil() : null;
});
}
/**
* Remove a set of listeners from the dispatcher.
*
* @param string $event
* @return void
*/
public function forget($event)
{
if (Str::contains($event, '*')) {
unset($this->wildcards[$event]);
} else {
unset($this->listeners[$event]);
}
}
/**
* Forget all of the pushed listeners.
*
* @return void
*/
public function forgetPushed()
{
foreach ($this->listeners as $key => $value) {
if (Str::endsWith($key, '_pushed')) {
$this->forget($key);
}
}
}
/**
* Get the queue implementation from the resolver.
*
* @return \Illuminate\Contracts\Queue\Queue
*/
protected function resolveQueue()
{
return call_user_func($this->queueResolver);
}
/**
* Set the queue resolver implementation.
*
* @param callable $resolver
* @return $this
*/
public function setQueueResolver(callable $resolver)
{
$this->queueResolver = $resolver;
return $this;
}
}