IoC container - Laravel Groningen

Did you know your IoC container can do a whole lot more than just constructor injection? Besides that it is actually packed with features. Inflectors, resolving callbacks, aliasing, method invocation to name a few. In this talk you will learn how to leverage the power of a great container and service providers to write better, loosely coupled code. Well designed code put together by your IoC container will make your applications SOLID, modular, lean and decoupled from the framework!

Transcript

1. IOC container
   @hannesvdvreken
   Laravel Groningen
   

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2. Hi, my name is Hannes.
   

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3. !
   

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4. madewithlove.be
   

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5. IoC Container
   

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6. I
   O
   C
   

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7. International
   O
   C
   

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8. International
   Olympic
   C
   

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9. International
   Olympic
   Committee
   

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10. International
    Olympic
    Committee
    

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11. WHAT IS IOC?
    IoC == Inversion of Control
    

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12. But first:
    Design patterns
    WHAT IS IOC?
    

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

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14. 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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15. 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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16. 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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17. 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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18. 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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19. class Service
    {
    public function __construct(FtpStorage $storage)
    {

    $this->storage = $storage;
    }
    }
    WHAT IS IOC?
    

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

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

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22. class Service
    {
    public function __construct(Storage $storage)
    {

    $this->storage = $storage;
    }
    }
    WHAT IS IOC?
    

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23. 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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24. 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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25. 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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26. 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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27. FtpStorage
    Service
    depends on
    depends on
    Ftp
    WHAT IS IOC?
    

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

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

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

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31. Don’t create these instances
    yourself
    WHAT IS IOC?
    

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32. $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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33. Inversion of Control
    IoC container to the rescue
    WHAT IS IOC?
    

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

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35. 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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36. Automatic constructor
    injection
    

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

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38. Constructor injection
    CONSTRUCTOR INJECTION
    

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

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40. Reflection
    CONSTRUCTOR INJECTION
    

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

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42. Recursively
    CONSTRUCTOR INJECTION
    

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43. Helping the container
    

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44. Service Providers
    REGISTRATION
    

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

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

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

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48. Register bindings
    in the register method
    REGISTRATION
    

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

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

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

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

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53. Bind everything with its class
    name
    REGISTRATION - BINDING
    

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54. Unless you bind multiple
    versions
    REGISTRATION - BINDING
    

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

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56. Bind a concretion for every
    interface
    REGISTRATION - BINDING
    

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

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58. Contextual binding
    REGISTRATION - CONTEXTUAL BINDING
    

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

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

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61. $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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62. Inflection
    REGISTRATION
    

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

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

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

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

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67. 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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68. 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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69. Method injection
    REGISTRATION - CONTAINER EVENTS
    

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

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

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

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

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

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

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

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

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79. Using the container
    

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

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

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

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

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85. Bonus
    

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86. Solving circular
    dependencies
    BONUS - CIRCULAR DEPENDENCIES
    

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

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

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89. recap:
    Reflection
    Binding
    Calling code
    Bonus
    

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90. @hannesvdvreken
    Thank you!
    Laravel Groningen
    

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91. @hannesvdvreken
    Time for questions.
    Laravel Groningen
    

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92. • http:/
    /mwl.be
    REFERENCES
    

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