A resource orientated framework using the DI/AOP/REST Triangle

DI, AOP and REST are powerful patterns that developers should have in their tool belts. Akihito’s open source BEAR.Sunday framework goes one step further and uses them as the basis for strong architectural design for large scale PHP applications.
With very few components of its own, BEAR.Sunday is a fantastic example of how a framework can be built using existing components and libraries from other frameworks, yet offer even further simplicity beauty and power by holding on to these 3 core design patterns.

phpnw13
http://conference.phpnw.org.uk/phpnw13/schedule/akihito-koriyama-richard-mcintyre/

joindin
http://joind.in/talk/view/9302

Transcript

1. A resource orientated framework
   using the DI /AOP/REST Triangle
   

   View Slide

2. About Us
   • Akihito Koriyama
   • A Tokyo based freelance PHP architect
   • BEAR.Sunday lead, Aura PHP member
   • Richard McIntyre
   • Manchester / leeds based freelance PHP
   developer
   • BEAR.Sunday contributor, Lithium member
   

   View Slide

3. About Us
   • Akihito Koriyama
   • A Tokyo based freelance PHP architect
   • BEAR.Sunday lead, Aura PHP member
   • Richard McIntyre
   • Manchester / Leeds based freelance PHP
   developer
   • BEAR.Sunday contributor, Lithium member
   

   View Slide

4. View Slide

5. BEAR.Sunday is an application framework.
   But it offers no libraries.
   (We have good stuff)
   

   View Slide

6. instead, it offers three object frameworks.
   

   View Slide

7. What is a framework ?
   

   View Slide

8. “imposes a set of design constraints on end-user code.”
   

   View Slide

9. View Slide

10. View Slide

11. 3.hypermedia framework
    

    View Slide

12. DI
    AOP
    REST
    

    View Slide

13. DI Benefits
    • Dependency Inversion Principle
    • Clear separation of object instantiation and object
    usage
    • Object delivery
    

    View Slide

14. DIP
    • Code should depend on
    things that are at the same
    or higher level of
    abstraction
    • High level policy should not
    depend on low level details
    

    View Slide

15. “The principle of dependency inversion is at the
    root of many of the benefits claimed for object-
    oriented technology.
    Its proper application is necessary for the creation
    of reusable frameworks”
    

    View Slide

16. Ray.DI
    Dependency Injection Framework
    

    View Slide

17. /**
    * @Inject
    */
    public function __construct(RenderInterface $renderer)
    {
    ...
    1.annotate at injection point
    class RendererModule extends AbstractModule
    {
    protected function configure()
    {
    $this->bind('RenderInterface')
    ->to('HalRenderer')
    ->in(Scope::SINGLETON);
    }
    $injector = Inject::create([new RendererModule]];
    2 bind abstraction to concretion
    3.create an injector
    

    View Slide

18. /**
    * @Inject
    */
    public function __construct(RenderInterface $renderer)
    {
    ...
    1.annotate at injection point
    class RendererModule extends AbstractModule
    {
    protected function configure()
    {
    $this->bind('RenderInterface')
    ->to('HalRenderer')
    ->in(Scope::SINGLETON);
    }
    $injector = Inject::create([new RendererModule]];
    2. bind abstraction to concretion
    3.create an injector
    

    View Slide

19. /**
    * @Inject
    */
    public function __construct(RenderInterface $renderer)
    {
    ...
    1.annotate at injection point
    class RendererModule extends AbstractModule
    {
    protected function configure()
    {
    $this->bind('RenderInterface')
    ->to('HalRenderer')
    ->in(Scope::SINGLETON);
    }
    $injector = Inject::create([new RendererModule]];
    2 bind abstraction to concretion
    3.create an injector
    

    View Slide

20. $user = $injector->getInstance('UserInterface');
    4. Get an object graph from the $injector
    User Renderer
    Renderer Interface
    depends
    A
    B
    

    View Slide

21. QSPDFEVSBM
    PCKFDUPSJFUOFE
    DPNQJMBUJPO
    SVOUJNF
    Implement the structure, not a procedure
    

    View Slide

22. class RendererModule extends AbstractModule
    {
    protected function configure()
    {
    $this
    ->bind('RenderInterface')
    ->to('HalRenderer')
    ->in(Scope::SINGLETON);
    }
    }
    Only use concrete classes in compilation
    

    View Slide

23. Only abstraction in runtime
    /**
    * @Inject
    */
    public function __construct(RenderInterface $renderer)
    {
    

    View Slide

24. DI Best practice
    “Your code should deal directly with the Injector
    as little as possible. Instead, you want to bootstrap
    your application by injecting one root object.”
    

    View Slide

25. Application = one root object
    

    View Slide

26. Application class
    

    View Slide

27. View Slide

28. Application is root object
    retrieved with injector:
    $injector = Injector::create([new AppModule($context)]];
    $app = $injector->getInstance(‘AppInterface’);
    

    View Slide

29. Application has dependency.
    

    View Slide

30. View Slide

31. Dependencies have other dependencies
    Each object either contains or belongs to.
    

    View Slide

32. You get a application object graph.
    huge, but can be stored one single root value $app
    

    View Slide

33. "QQMJDBUJPODBOCFTFSJBMJ[FE
    $app can be serialized and stored
    Injection is reused beyond requests.
    

    View Slide

34. $app
    Object
    i/f
    i/f
    Object
    i/f i/f
    Object
    Router
    Response
    JSON
    XM
    L
    1st framework: DI Framework
    • annotations based DI framework w/ binding DSL
    • compilation / runtime separation
    • use only “plug/abstraction” at runtime
    • application a single large cached object
    • focus on structure not behavior
    

    View Slide

35. Aspect Oriented Programing
    

    View Slide

36. What is AOP?
    Cache
    Log
    Auth
    A programming paradigm that aims to increase modularity
    by allowing the separation of cross-cutting concerns
    

    View Slide

37. /**
    * @Cache
    */
    public function onGet($id)
    {
    // ...
    $this->body = $stmt->fetchAll(PDO::FETCH_ASSOC);
    return $this;
    }
    class Post extends AppModel {
    public function newest() {
    $result = Cache::read('newest_posts', 'longterm');
    if (!$result) {
    $result = $this->find('all');
    Cache::write('newest_posts', $result, 'longterm');
    }
    return $result;
    }
    }
    

    View Slide

38. M
    C
    I I
    AOP
    

    View Slide

39. M
    C
    Cache
    Cache is called by method invocation,
    If the cache is warm the model is never called.
    $obj->read(2);
    Miss !
    

    View Slide

40. Aspects
    Core Concern Cross Cutting Concern
    Separation
    

    View Slide

41. Rock Concert Example
    

    View Slide

42. interface MethodInterceptor
    {
    public function invoke(MethodInvocation $invocation);
    }
    $invocation->proceed(); // invoked method
    $object = $invocation->getThis(); // get source object
    $args = $invocation->getArgs(); // get arguments
    

    View Slide

43. class Transactional implements MethodInterceptor
    {
    public function invoke(MethodInvocation $invocation)
    {
    $object = $invocation->getThis();
    $ref = new ReflectionProperty($object, 'db');
    $ref->setAccessible(true);
    $db = $ref->getValue($object);
    $db->beginTransaction();
    try {
    $invocation->proceed();
    $db->commit();
    } catch (Exception $e) {
    $db->rollback();
    }
    }
    }
    `Transactional`interceptor
    Core Concern
    Cross Cutting Concern
    

    View Slide

44. class CacheInterceptor implements MethodInterceptor
    {
    public function invoke(MethodInvocation $invocation)
    {
    $obj = $invocation->getThis();
    $args = $invocation->getArguments();
    $id = get_class($obj) . serialize($args);
    $saved = $this->cache->fetch($id);
    if ($saved) {
    return $saved;
    }
    $result = $invocation->proceed();
    $this->cache->save($id, $result);
    return $result;
    }
    }
    `Cache`interceptor
    Core Concern
    Cross Cutting Concern
    

    View Slide

45. 4JNQMZBOOPUBUF
    UIFODSFBUFZPVSCJOEJOH
    #JOE
    

    View Slide

46. Layering by context
    • MVC, Is 3 enough ?
    

    View Slide

47. API
    Client
    

    View Slide

48. API Log
    Client Valid Auth
    

    View Slide

49. API Log
    !7BMJE
    BENJO %&-&5&
    Client Valid Auth
    

    View Slide

50. Aspect layering by context
    Model
    Cache
    Form
    Transaction
    Auth
    Validation
    

    View Slide

51. class SandboxResourcePageIndexRay0000000071f9ab280000000033fb446fAop extends
    Sandbox\Resource\Page\Index implements Ray\Aop\WeavedInterface
    {
    private $rayAopIntercept = true;
    public $rayAopBind;
    public function onGet()
    {
    // native call
    if (!isset($this->rayAopBind[__FUNCTION__])) {
    return call_user_func_array('parent::' . __FUNCTION__, func_get_args());
    }
    // proceed source method from interceptor
    if (!$this->rayAopIntercept) {
    $this->rayAopIntercept = true;
    return call_user_func_array('parent::' . __FUNCTION__, func_get_args());
    }
    // proceed next interceptor
    $this->rayAopIntercept = false;
    $interceptors = $this->rayAopBind[__FUNCTION__];
    $annotation = isset($this->rayAopBind->annotation[__FUNCTION__]) ? $this->rayAopBind
    >annotation[__FUNCTION__] : null;
    $invocation = new \Ray\Aop\ReflectiveMethodInvocation(array($this, __FUNCTION__),
    func_get_args(), $interceptors, $annotation);
    return $invocation->proceed();
    }
    Under the hood: Method interception sub class is created
    in order enable this interception and keep type safety.
    

    View Slide

52. Runtime injection by aspect
    • method / parameter lookup
    • test friendly
    

    View Slide

53. 2nd framework: Aspect Oriented Framework
    • AOP alliance standard
    • Layering by context
    • Type safe
    • Runtime injection
    

    View Slide

54. View Slide

55. Hypermedia framework for object as a service
    It allows objects to have RESTful web service benefits
    such as client-server, uniform interface, statelessness,
    resource expression with mutual connectivity and
    layered components.
    

    View Slide

56. class Author extends ResourceObject
    {
    public $code = 200;
    public $headers = [];
    public $body = [];
    /**
    * @Link(rel="blog", href="app://self/blog/post?author_id={id}")
    */
    public function onGet($id)
    {
    ... // change own state
    return $this;
    }
    public function onPost($name)
    {
    $this->code = 201; // created
    return $this;
    }
    public function onPut($id, $name)
    

    View Slide

57. $user = $resource
    ->get
    ->uri('app://self/user')
    ->withQuery(['id' => 1])
    ->eager
    ->request();
    var_dump($user->body);
    // Array
    // (
    // [name] => John
    // [age] => 15
    //)
    echo $user;
    // John
    // 15
    public function onGet($id)
    {
    $this[‘name’] = ‘John’;
    $this[‘age’] = 15;
    return $this;
    }
    User
    Profile
    Friend
    

    View Slide

58. $order = $resource
    ->post
    ->uri('app://self/order')
    ->withQuery(['drink' => 'latte'])
    ->eager
    ->request();
    $payment = [
    'credit_card_number' => '123456789',
    'expires' => '07/07',
    'name' => 'Koriym',
    'amount' => '4.00'
    ];
    // Now use a hyperlink to pay
    $response = $resource->href('pay', $payment);
    echo $response->code; // 201
    Hypermedia as the Engine of Application State
    

    View Slide

59. class Order extends ResourceObject
    {
    /**
    *
    * @Link(rel="pay", method="put",
    href="app://self/payment{?order_id,card_number,amount}")
    */
    public function onPost($drink)
    {
    // data store here
    $this['drink'] = $drink;
    $this['order_id'] = $orderId;
    // created
    $this->code = 201;
    return $this;
    }
    Hypermedia as the Engine of Application State
    

    View Slide

60. Order Payment
    hyper reference: pay
    HyperMedia Driven API
    

    View Slide

61. The key of success of web
    • URI
    • Unified Interface
    • Hyperlink
    

    View Slide

62. • API is hub
    • API is core value
    API driven development
    DB Mobil
    e
    Web
    API
    Cloud
    Moc
    k
    URI
    API
    API
    

    View Slide

63. http://blog.8thlight.com/uncle-bob/2012/08/13/the-clean-architecture.html
    

    View Slide

64. Layered Resource
    UI
    Mobile
    Web
    Page Resource
    App script
    App Resource
    Entity
    

    View Slide

65. View Slide

66. View Slide

67. View Slide

68. View Slide

69. Performance
    • annotation ? dependency injection ?
    method interception ? DSL ? named parameter ?
    • Fast
    • cache all compiled object
    • http friendly architecture
    

    View Slide

70. Scale
    • “model proxy” pattern
    • ‘app://self/blog/entry’ can be anything.
    • contextual injection makes db scale easy
    

    View Slide

71. Hard spot / Soft spot
    • DI configure hardspot. QFSTZTUFN
    • Aop configure softspot, change on request
    

    View Slide

72. Connecting frameworks
    • DI - object as dependency
    • AOP - domain logic to application logic
    • Hypermedia - resource to resource
    

    View Slide

73. Abstraction frameworks
    • DSL
    • Annotation
    • URI
    • Interface
    • Aspects
    • Hypermedia
    

    View Slide

74. View Slide

75. “Zen” framework
    

    View Slide

76. Thanks.
    Arigato
    http://www.flickr.com/photos/stevehoad/4678289858/
    @mackstar
    @koriym
    

    View Slide