Added EventDispatcher

config/app.php

@@ -5,12 +5,12 @@
 return [
     // Service providers
     'providers'  => [
-
         // Application bootstrap
         \Engelsystem\Logger\LoggerServiceProvider::class,
         \Engelsystem\Exceptions\ExceptionsServiceProvider::class,
         \Engelsystem\Config\ConfigServiceProvider::class,
         \Engelsystem\Helpers\ConfigureEnvironmentServiceProvider::class,
+        \Engelsystem\Events\EventsServiceProvider::class,
 
         // Request handling
         \Engelsystem\Http\UrlGeneratorServiceProvider::class,
@@ -55,4 +55,15 @@ return [
         // Handle request
         \Engelsystem\Middleware\RequestHandler::class,
     ],
+
+    // Event handlers
+    'event-handlers' => [
+        // 'event' => [
+        //      a list of
+        //      'Class@method' or 'Class' (which uses @handle),
+        //      ['Class', 'method'],
+        //      callable like [$instance, 'method] or 'function'
+        //      or $function
+        // ]
+    ],
 ];

src/Config/ConfigServiceProvider.php

@@ -11,7 +11,7 @@ use Illuminate\Database\QueryException;
 class ConfigServiceProvider extends ServiceProvider
 {
     /** @var array */
-    protected $configFiles = ['config.default.php', 'config.php'];
+    protected $configFiles = ['app.php', 'config.default.php', 'config.php'];
 
     /** @var EventConfig */
     protected $eventConfig;

src/Events/EventDispatcher.php

@@ -0,0 +1,86 @@
+<?php
+
+namespace Engelsystem\Events;
+
+use Illuminate\Support\Arr;
+use Illuminate\Support\Str;
+
+class EventDispatcher
+{
+    /** @var callable[] */
+    protected $listeners;
+
+    /**
+     * @param array|string    $events
+     * @param callable|string $listener
+     */
+    public function listen($events, $listener): void
+    {
+        foreach ((array)$events as $event) {
+            $this->listeners[$event][] = $listener;
+        }
+    }
+
+    /**
+     * @param string $event
+     */
+    public function forget($event): void
+    {
+        unset($this->listeners[$event]);
+    }
+
+    /**
+     * @param string|object $event
+     * @param array|mixed   $payload
+     * @param bool          $halt
+     *
+     * @return array|mixed|null
+     */
+    public function fire($event, $payload = [], $halt = false)
+    {
+        return $this->dispatch($event, $payload, $halt);
+    }
+
+    /**
+     * @param string|object $event
+     * @param array|mixed   $payload
+     * @param bool          $halt     Stop on first non-null return
+     *
+     * @return array|null|mixed
+     */
+    public function dispatch($event, $payload = [], $halt = false)
+    {
+        if (is_object($event)) {
+            $payload = $event;
+            $event = get_class($event);
+        }
+
+        $listeners = [];
+        if (isset($this->listeners[$event])) {
+            $listeners = $this->listeners[$event];
+        }
+
+        $responses = [];
+        foreach ($listeners as $listener) {
+            if (!is_callable($listener) && is_string($listener) && !Str::contains($listener, '@')) {
+                $listener = $listener . '@handle';
+            }
+
+            $response = app()->call($listener, ['event' => $event] + Arr::wrap($payload));
+
+            // Return the events response
+            if ($halt && !is_null($response)) {
+                return $response;
+            }
+
+            // Stop further event propagation
+            if ($response === false) {
+                break;
+            }
+
+            $responses[] = $response;
+        }
+
+        return $halt ? null : $responses;
+    }
+}

src/Events/EventsServiceProvider.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace Engelsystem\Events;
+
+use Engelsystem\Config\Config;
+use Engelsystem\Container\ServiceProvider;
+
+class EventsServiceProvider extends ServiceProvider
+{
+    public function register()
+    {
+        $dispatcher = $this->app->make(EventDispatcher::class);
+
+        $this->app->instance(EventDispatcher::class, $dispatcher);
+        $this->app->instance('events.dispatcher', $dispatcher);
+
+        $this->registerEvents($dispatcher);
+    }
+
+    /**
+     * @param EventDispatcher $dispatcher
+     */
+    protected function registerEvents(EventDispatcher $dispatcher)
+    {
+        /** @var Config $config */
+        $config = $this->app->get('config');
+
+        foreach ($config->get('event-handlers', []) as $event => $handlers) {
+            foreach ((array)$handlers as $handler) {
+                $dispatcher->listen($event, $handler);
+            }
+        }
+    }
+}

tests/Unit/Config/ConfigServiceProviderTest.php

@@ -27,11 +27,11 @@ class ConfigServiceProviderTest extends ServiceProviderTest
         /** @var Config|MockObject $config */
         list($app, $config) = $this->getConfiguredApp(__DIR__ . '/../../../config');
 
-        $this->setExpects($config, 'set', null, null, $this->exactly(2));
+        $this->setExpects($config, 'set', null, null, $this->exactly(3));
-        $config->expects($this->exactly(3))
+        $config->expects($this->exactly(4))
             ->method('get')
             ->with(null)
-            ->willReturnOnConsecutiveCalls([], [], ['lor' => 'em']);
+            ->willReturnOnConsecutiveCalls([], [], [], ['lor' => 'em']);
 
         $configFile = __DIR__ . '/../../../config/config.php';
         $configExists = file_exists($configFile);

tests/Unit/Events/EventDispatcherTest.php

@@ -0,0 +1,161 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Events;
+
+use Engelsystem\Events\EventDispatcher;
+use Engelsystem\Test\Unit\TestCase;
+
+class EventDispatcherTest extends TestCase
+{
+    /** @var array */
+    protected $firedEvents = [];
+
+    /**
+     * @covers \Engelsystem\Events\EventDispatcher::listen
+     * @covers \Engelsystem\Events\EventDispatcher::fire
+     */
+    public function testListen(): void
+    {
+        $event = new EventDispatcher();
+        $event->listen('foo', [$this, 'eventHandler']);
+        $event->listen(['foo', 'bar'], [$this, 'eventHandler']);
+
+        $event->fire('foo');
+        $event->fire('bar', 'Test!');
+
+        $this->assertEquals(
+            ['foo' => ['count' => 2, ['foo'], ['foo']], 'bar' => ['count' => 1, ['bar', 'Test!']]],
+            $this->firedEvents
+        );
+    }
+
+    /**
+     * @covers \Engelsystem\Events\EventDispatcher::forget
+     */
+    public function testForget(): void
+    {
+        $event = new EventDispatcher();
+        $event->forget('not-existing-event');
+
+        $event->listen('test', [$this, 'eventHandler']);
+        $event->forget('test');
+
+        $event->fire('test');
+
+        $this->assertEquals([], $this->firedEvents);
+    }
+
+    /**
+     * @covers \Engelsystem\Events\EventDispatcher::dispatch
+     */
+    public function testDispatchNotExistingEvent(): void
+    {
+        $event = new EventDispatcher();
+        $response = $event->fire('not-existing-event');
+
+        $this->assertEquals([], $response);
+    }
+
+    /**
+     * @covers \Engelsystem\Events\EventDispatcher::dispatch
+     */
+    public function testDispatchObject(): void
+    {
+        $event = new EventDispatcher();
+        $event->listen(static::class, [$this, 'eventHandler']);
+        $event->fire($this);
+
+        $this->assertEquals([static::class => ['count' => 1, [static::class, $this]]], $this->firedEvents);
+    }
+
+    /**
+     * @covers \Engelsystem\Events\EventDispatcher::dispatch
+     */
+    public function testDispatchHalt(): void
+    {
+        $event = new EventDispatcher();
+        $event->listen('test', [$this, 'returnNull']);
+        $event->listen('test', [$this, 'returnData']);
+        $event->listen('test', [$this, 'eventHandler']);
+        $response = $event->dispatch('test', [], true);
+
+        $this->assertEquals(['example' => 'data'], $response);
+        $this->assertEquals([], $this->firedEvents);
+
+        $event = new EventDispatcher();
+        $response = $event->dispatch('test', [], true);
+        $this->assertNull($response);
+    }
+
+    /**
+     * @covers \Engelsystem\Events\EventDispatcher::dispatch
+     */
+    public function testDispatchStopPropagation(): void
+    {
+        $event = new EventDispatcher();
+        $event->listen('test', [$this, 'returnNull']);
+        $event->listen('test', [$this, 'returnFalse']);
+        $event->listen('test', [$this, 'eventHandler']);
+        $response = $event->dispatch('test');
+
+        $this->assertEquals([null], $response);
+        $this->assertEquals([], $this->firedEvents);
+    }
+
+    /**
+     * @covers \Engelsystem\Events\EventDispatcher::dispatch
+     */
+    public function testDispatchFallbackHandleMethod(): void
+    {
+        $event = new EventDispatcher();
+        $event->listen('test', EventDispatcherTest::class);
+        $response = $event->dispatch('test', [], true);
+
+        $this->assertEquals(['default' => 'handler'], $response);
+    }
+
+    /**
+     * @param string $event
+     */
+    public function eventHandler(string $event): void
+    {
+        if (!isset($this->firedEvents[$event])) {
+            $this->firedEvents[$event] = ['count' => 0];
+        }
+
+        $this->firedEvents[$event]['count']++;
+        $this->firedEvents[$event][] = func_get_args();
+    }
+
+    /**
+     * @return null
+     */
+    public function returnNull()
+    {
+        return null;
+    }
+
+    /**
+     * @return bool
+     */
+    public function returnFalse(): bool
+    {
+        return false;
+    }
+
+    /**
+     * @return array
+     */
+    public function returnData(): array
+    {
+        return ['example' => 'data'];
+    }
+
+    /**
+     * @return array
+     */
+    public function handle(): array
+    {
+        return ['default' => 'handler'];
+    }
+}

tests/Unit/Events/EventsServiceProviderTest.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Events;
+
+use Engelsystem\Config\Config;
+use Engelsystem\Events\EventDispatcher;
+use Engelsystem\Events\EventsServiceProvider;
+use Engelsystem\Test\Unit\ServiceProviderTest;
+
+class EventsServiceProviderTest extends ServiceProviderTest
+{
+    /**
+     * @covers \Engelsystem\Events\EventsServiceProvider::register
+     * @covers \Engelsystem\Events\EventsServiceProvider::registerEvents
+     */
+    public function testRegister()
+    {
+        $dispatcher = $this->createMock(EventDispatcher::class);
+        $this->app->instance(EventDispatcher::class, $dispatcher);
+        $dispatcher->expects($this->exactly(3))
+            ->method('listen')
+            ->withConsecutive(
+                ['test.event', 'someFunction'],
+                ['another.event', 'Foo\Bar@baz'],
+                ['another.event', [$this, 'someMethod']]
+            );
+
+        $config = new Config([
+            'event-handlers' => [
+                'test.event' => 'someFunction',
+                'another.event' => ['Foo\Bar@baz', [$this, 'someMethod']]
+            ]
+        ]);
+        $this->app->instance('config', $config);
+
+        /** @var EventsServiceProvider $provider */
+        $provider = $this->app->make(EventsServiceProvider::class);
+
+        $provider->register();
+    }
+}