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IOC container @hannesvdvreken Laravel Groningen

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Hi, my name is Hannes.

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!

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madewithlove.be

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IoC Container

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I O C

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International O C

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International Olympic C

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International Olympic Committee

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International Olympic Committee

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WHAT IS IOC? IoC == Inversion of Control

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But first: Design patterns WHAT IS IOC?

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class Service { public function calculate() { // Get stuff from FTP. // Do calculations. // Return result. } } WHAT IS IOC?

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class Service { public function __construct(Ftp $ftp) { } public function calculate() { // Get stuff from FTP. // Do calculations. // Return result. } } WHAT IS IOC?

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class Service { public function __construct(Ftp $ftp) { } public function calculate() { // Get stuff from FTP. // Add caching to prevent hitting FTP over and over again // Do calculations. // Return result. } } WHAT IS IOC?

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class Service { public function __construct(Ftp $ftp) { } public function calculate() { // Get stuff from FTP. // Add caching to prevent hitting FTP over and over again // Log that FTP is accessed. // Do calculations. // Return result. } } WHAT IS IOC?

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class Service { public function __construct(Ftp $ftp) { } public function calculate() { // Get stuff from FTP. // Add caching to prevent hitting FTP over and over again // Log that FTP is accessed. // Do calculations. // Return result. } } WHAT IS IOC?

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class FtpStorage { public function __construct(Ftp $ftp) { $this->ftp = $ftp; } public function get($key) { // Get it. // Cache it. // Log it. // Return it. } } WHAT IS IOC?

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class Service { public function __construct(FtpStorage $storage) {
 $this->storage = $storage; } } WHAT IS IOC?

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interface Storage { public function get($key); } WHAT IS IOC?

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class FtpStorage implements Storage { public function __construct(Ftp $ftp) { $this->ftp = $ftp; } public function get($key) { … } } WHAT IS IOC?

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class Service { public function __construct(Storage $storage) {
 $this->storage = $storage; } } WHAT IS IOC?

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class CacheDecorator implements Storage { public function __construct(Cache $cache, Storage $storage) {…} public function get($key) { return $this->cache->remember($key, 60, function () { return $this->storage->get($key); }); } } WHAT IS IOC?

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class LogDecorator implements Storage { public function __construct(LoggerInterface $log, Storage $storage) {…} public function get($key) { $this->log->info('Retrieved value for '.$key); return $this->storage->get($key); } } WHAT IS IOC?

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class FtpStorage implements Storage { public function __construct(Ftp $ftp) { $this->ftp = $ftp; } public function get($key) { // Get it and return it. } } WHAT IS IOC?

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Dependency inversion: Interface + implementation Dependency injection: Injecting `Storage` into `Service` Inversion of Control: The container builds your objects and calls them WHAT IS IOC?

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FtpStorage Service depends on depends on Ftp WHAT IS IOC?

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FtpStorage implements Storage Service depends on depends on Ftp WHAT IS IOC?

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FtpStorage Storage CacheDecorator Service LogDecorator S3Storage depends on WHAT IS IOC? implements

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new Service(new FtpStorage(new Ftp($settings))); WHAT IS IOC?

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Don’t create these instances yourself WHAT IS IOC?

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$container->get(Service::class); 1) Make FtpStorage 2) Wrap it with LogDecorator 3) Wrap LogDecorator instance with CacheDecorator 4) New up Service with CacheDecorator instance. WHAT IS IOC?

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Inversion of Control IoC container to the rescue WHAT IS IOC?

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IoC container is here to help you with Composition WHAT IS IOC?

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illuminate/container league/container symfony/dependency-injection aura/di zendframework/zend-di … container-interop/container-interop psr/container (PSR-11) CONSTRUCTOR INJECTION

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Automatic constructor injection

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class SendInvoice { public function __construct(Mailer $mailer) { $this->mailer = $mailer; } public function listen(InvoiceGeneratedEvent $event) { … } } CONSTRUCTOR INJECTION

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Constructor injection CONSTRUCTOR INJECTION

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$app->make(SendInvoice::class); CONSTRUCTOR INJECTION

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Reflection CONSTRUCTOR INJECTION

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(new \ReflectionClass($class)) ->getConstructor() ->getParameters(); CONSTRUCTOR INJECTION

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Recursively CONSTRUCTOR INJECTION

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Helping the container

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Service Providers REGISTRATION

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class ServiceProvider { public function register() { … } public function boot(Dispatcher $events) } REGISTRATION

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class ServiceProvider { public function register() {…} public function boot(Dispatcher $events) { … } } REGISTRATION

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class ServiceProvider { protected $defer = true; public function register() {…} public function provides() { return [ Mailer::class, SwiftMailer::class, ]; } } REGISTRATION

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Register bindings in the register method REGISTRATION

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$this->app->bind( MailerContract::class, SwiftMailer::class ); REGISTRATION - BINDING

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$this->app->bind(Mailer::class, function () { $mailer = new SwiftMailer(); return new LogDecorator($mailer); }); REGISTRATION - BINDING

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$this->app->singleton(Mailer::class, function () { … }); REGISTRATION - BINDING

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$this->app->alias( Mailer::class, 'mailer' ); REGISTRATION - BINDING

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Bind everything with its class name REGISTRATION - BINDING

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Unless you bind multiple versions REGISTRATION - BINDING

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$this->app->bind('fs.photos', function () {}); $this->app->bind('fs.files', function () {}); REGISTRATION - BINDING

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Bind a concretion for every interface REGISTRATION - BINDING

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REGISTRATION - BINDING $this->app->bind( LoggerInterface::class, Monolog::class );

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Contextual binding REGISTRATION - CONTEXTUAL BINDING

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$this->app ->when(PhotosController::class) ->needs(FilesystemInterface::class) ->give('fs.photos'); REGISTRATION - CONTEXTUAL BINDING

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No more DB::connection('db1')->table($table)->…; REGISTRATION - CONTEXTUAL BINDING

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$this->app->bind('db.1', function () { return $this->app['db'] ->connection('db1'); }); $this->app ->when(EventListener::class) ->needs(ConnectionInterface::class) ->give('db.1'); REGISTRATION - CONTEXTUAL BINDING

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Inflection REGISTRATION

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Inflection (aka “container events”) REGISTRATION - CONTAINER EVENTS

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$this->app->resolving( function (Foo $foo) {…} ); REGISTRATION - CONTAINER EVENTS

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use App\Contracts\EnvironmentAware; $this->app->resolving( function (EnvironmentAware $object) { $object->setEnv( $this->app->environment() ); } ); REGISTRATION - CONTAINER EVENTS

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interface EnvironmentAware { public function setEnv($env); } REGISTRATION - CONTAINER EVENTS

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trait EnvironmentAware { public function setEnv($env) { $this->env = $env; } private function isEnv($envs): bool { return in_array($this->env, (array) $envs); } } REGISTRATION - CONTAINER EVENTS

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public function boot() { $this->app->resolving(function (LoggerAwareInterface $loggingObject) { $logger = $this->app->make(PsrLoggerInterface::class); $loggingObject->setLogger($logger); }); } REGISTRATION - CONTAINER EVENTS

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Method injection REGISTRATION - CONTAINER EVENTS

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Also useful for: - Quickly injecting stuff REGISTRATION - CONTAINER EVENTS

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interface CommandBusAware trait CommandBusAware interface EventDispatcherAware trait EventDispatcherAware REGISTRATION - CONTAINER EVENTS

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Also useful for: - Quickly injecting stuff REGISTRATION - CONTAINER EVENTS

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Also useful for: - Quickly injecting stuff - Injecting soft dependencies REGISTRATION - CONTAINER EVENTS

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$this->app->resolving(function (Mailer $mailer) { $mailer->setQueueResolver(function () { return $this->app->make(Queue::class); }); ); REGISTRATION - CONTAINER EVENTS

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Also useful for: - Quickly injecting stuff - Injecting soft dependencies REGISTRATION - CONTAINER EVENTS

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Also useful for: - Quickly injecting stuff - Injecting soft dependencies - Setting configurable values REGISTRATION - CONTAINER EVENTS

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$this->app->resolving(function (Validator) { $fileTypes = $app['config']->get(…) $validator->setAllowedFileTypes($fileTypes); ); REGISTRATION - CONTAINER EVENTS

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Using the container

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Preferably only for - Factories - Event Dispatchers - Router - Command Bus CALLING THE CONTAINER

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$this->app->make('fs'); $this->app->make('fs', […]); $this->app->bind( 'fs', function ($app, $args) {…} ); CALLING THE CONTAINER

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$this->app->call(function (Mailer $mailer) {}); $this->app->call([$listener, 'handle']); $this->app->call('Listener::handle'); $this->app->call('Listener@handle'); CALLING THE CONTAINER

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$func = $this->app->wrap('Listener@handle'); $func();

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public function wrap($callback) { return function () { $this->call($callback); }; }

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Bonus

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Solving circular dependencies BONUS - CIRCULAR DEPENDENCIES

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$mailer = new Mailer(QueueInterface $queue); $queue = new Queue(MailerInterface $mailer); BONUS - CIRCULAR DEPENDENCIES

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$mailer = new Mailer(); $queue = new Queue(MailerInterface $mailer); $mailer->setQueueResolver(function () { return $this->app->make('queue'); }); BONUS CIRCULAR DEPENDENCIES

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recap: Reflection Binding Calling code Bonus

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@hannesvdvreken Thank you! Laravel Groningen

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@hannesvdvreken Time for questions. Laravel Groningen

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• http:/ /mwl.be REFERENCES