Create Clean Code with AOP

International PHP Conference, Spring Edition 2010

Robert Lemke

Create Clean Code with Aspect-Oriented Programming

Photo: Wolfgang Staudt

Robert Lemkechief architect of TYPO3 Phoenix and FLOW3

co-founder of the TYPO3 Association

34 years old

lives in Lübeck, Germany

1 wife, 1 daughter, 1 espresso machine

likes drumming

= Full Stack Application Framework

OOP Object-Oriented Programming

AOP Aspect-Oriented Programming

MVC Model View Controller

POPO Plain Old PHP Object

DI Dependency Injection DRY

YAGNI

CoC

TDD

LLATIP

Create Clean Code with AOP IPC SE 2010, Berlin

/** * Creates a new post * * @param \F3\Blog\Domain\Model\Post $newPost A fresh Post object which has not yet been * added to the repository * @return void */public function createAction(\F3\Blog\Domain\Model\Post $newPost) {

if ($this->policyService->isGranted($this->currentUser, __CLASS__, __METHOD__) { $this->blog->addPost($newPost);

$this->flashMessageContainer->add('Your new post was created.'); $this->systemLogger->log('A new post was created.', LOG_INFO); $this->notificationService->notify('A new post was created.', '[email protected]'); } else { $this->systemLogger->log('Someone tried to create a post.', LOG_WARNING); throw new \F3\FLOW3\Security\Exception\AccessDeniedException('Tried to create.'); } $this->redirect('index');}

Create Clean Code with AOP IPC SE 2010, Berlin

/** * Creates a new post * * @param \F3\Blog\Domain\Model\Post $newPost A fresh Post object which has not yet been * added to the repository * @return void */public function createAction(\F3\Blog\Domain\Model\Post $newPost) {

if ($this->authorizationService->isGranted($this->currentUser, __CLASS__, __METHOD__) { $this->blog->addPost($newPost);

$this->flashMessageContainer->add('Your new post was created.'); $this->systemLogger->log('A new post was created.', LOG_INFO); $this->notificationService->notify('A new post was created.', '[email protected]'); } else { $this->systemLogger->log('Someone tried to create a post.', LOG_WARNING); $this->flashMessageContainer->add('Access denied.'); } $this->redirect('index');}

Create Clean Code with AOP IPC SE 2010, Berlin

AOP

Create Clean Code with AOP IPC SE 2010, Berlin

Aspect-Oriented Programmingprogramming paradigm

separates concerns to improve modularization

OOP modularizes concerns into objects

AOP modularizes cross-cutting concerns into aspects

Create Clean Code with AOP IPC SE 2010, Berlin

/** * Creates a new post * * @param \F3\Blog\Domain\Model\Post $newPost A fresh Post object which has not yet been * added to the repository * @return void */public function createAction(\F3\Blog\Domain\Model\Post $newPost) { $this->blog->addPost($newPost); $this->flashMessageContainer->add('Your new post was created.'); $this->redirect('index');}

Create Clean Code with AOP IPC SE 2010, Berlin

Concerns?

Create Clean Code with AOP IPC SE 2010, Berlin

ConcernsSeparation of Concerns

group features and behavior into manageable parts

have a specific purpose and business to take care of

Cross-Cutting Concerns

are the party poopers who want to have a say in everything

Create Clean Code with AOP IPC SE 2010, Berlin

Cross-Cutting ConcernsLogging

Security

Persistence

Global Business Logic

Dirty Hacks

Create Clean Code with AOP IPC SE 2010, Berlin

We don't want infrastructure codein our models.

Create Clean Code with AOP IPC SE 2010, Berlin

We want to unit-test even cross-cutting concerns

Create Clean Code with AOP IPC SE 2010, Berlin

We want to centralize security-related code

Create Clean Code with AOP IPC SE 2010, Berlin

AOP Lingo

Create Clean Code with AOP IPC SE 2010, Berlin

AspectPart of the application where cross-cutting concerns are implemented

In FLOW3 aspects are classes annotated with @aspect

Create Clean Code with AOP IPC SE 2010, Berlin

Join PointIs a single point in the call graph

Method Execution

Exception

Represents an event, not a location

Create Clean Code with AOP IPC SE 2010, Berlin

PointcutA set of join points where advices could be executed

can be composed

can be named

Create Clean Code with AOP IPC SE 2010, Berlin

AdviceAction to take at a join points defined by the point cut

Inspiring people toshareHitchhiker's Guide to FLOW3

DEMO

Inspiring people toshareHitchhiker's Guide to FLOW3

Kinds of AdviceAdvice types supported by FLOW3:

@before@afterreturning@afterthrowing@after@around

Inspiring people toshareHitchhiker's Guide to FLOW3

Pointcut Designatorsmethod(F3\MyPackage\MyClass->myMethod())class(F3\MyPackage\MyClass)within(F3\MyPackage\MyInterface)classTaggedWith(someTag)methodTaggedWith(anotherTag)setting(Demo.Stuff.SomeSetting = "yeah, do it")ffiilter(F3\MyPackage\MyCustomFilterImplementation)

Inspiring people toshareHitchhiker's Guide to FLOW3

Runtime Evaluationsevaluate(coffee.kind == "Arabica")

Inspiring people toshareHitchhiker's Guide to FLOW3

Compound Pointcuts

! /**!  * @around method(.*Controller->(new|create|edit|update|delete)Action()) && ⏎ !methodTaggedWith(anybodyMayAccessThis)!  */! public function interceptMethodCalls($joinPoint) {

...}

Inspiring people toshareHitchhiker's Guide to FLOW3

DEMO

Inspiring people toshareHitchhiker's Guide to FLOW3

FLOW3's AOP implementationbased on proxy classes

unlike with most pre-processors line numbers stay the same

no scaffolding

0 Lines of generated code which need to be maintained by you

fast (on the second hit)

Inspiring people toshareHitchhiker's Guide to FLOW3

Create Clean Code with AOP IPC SE 2010, Berlin

Progress

FLOW3 1.0.0

Create Clean Code with AOP IPC SE 2010, Berlin

Further ReadingFLOW3 Websitehttp://flow3.typo3.org

TYPO3 Forgehttp://forge.typo3.org

Further Readinghttp://flow3.typo3.org/about/principles/further-reading

http://bit.ly/GoodAOPArticle

Create Clean Code with AOP IPC SE 2010, Berlin

Questions

Email: [email protected]: http://robertlemke.de/blogTwitter: @t3rob

Feedback: http://joind.in/1743