WebExpo 2010, Prague

Robert Lemke

Create Clean Code with Aspect-Oriented Programming

Photo: Robert Szlivka

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

www.typo3.org

www.typo3.org

Create Clean Code with AOP WebExpo 2010, Prague

www.typo3.org

= PHP 5.3 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

YAA

Create Clean Code with AOP WebExpo 2010, Prague

/** * 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.', 'robert@typo3.org'); } 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 WebExpo 2010, Prague

/** * 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.', 'robert@typo3.org'); } 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 WebExpo 2010, Prague

Create Clean Code with AOP WebExpo 2010, Prague

AOP

Create Clean Code with AOP WebExpo 2010, Prague

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 WebExpo 2010, Prague

/** * 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 WebExpo 2010, Prague

Concerns?

Create Clean Code with AOP WebExpo 2010, Prague

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 WebExpo 2010, Prague

Cross-Cutting ConcernsLogging

Security

Persistence

Global Business Logic

Dirty Hacks

Create Clean Code with AOP WebExpo 2010, Prague

We don't want infrastructure codein our models.

Create Clean Code with AOP WebExpo 2010, Prague

We want to unit-test even cross-cutting concerns

Create Clean Code with AOP WebExpo 2010, Prague

We want to centralize security-related code

Create Clean Code with AOP WebExpo 2010, Prague

AOP Lingo

Create Clean Code with AOP WebExpo 2010, Prague

AspectPart of the application where cross-cutting concerns are implemented

In FLOW3 aspects are classes annotated with @aspect

Create Clean Code with AOP WebExpo 2010, Prague

Join PointIs a single point in the call graph

Method Execution

Exception

Represents an event, not a location

Create Clean Code with AOP WebExpo 2010, Prague

PointcutA set of join points where advices could be executed

can be composed

can be named

Create Clean Code with AOP WebExpo 2010, Prague

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

Inspiring people toshareHitchhiker's Guide to FLOW3

Create Clean Code with AOP WebExpo 2010, Prague

Progress

FLOW3 1.0.0

Create Clean Code with AOP WebExpo 2010, Prague

Further ReadingFLOW3 Websitehttp://flow3.typo3.org

FLOW3 Downloadhttp://flow3.typo3.org/downloadgit://git.typo3.org/FLOW3/Distributions/Base.git

TYPO3 Forgehttp://forge.typo3.org

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

Create Clean Code with AOP WebExpo 2010, Prague

Questions

Email: robert@typo3.orgBlog: http://robertlemke.de/blogTwitter: @t3rob

Slides: http://slideshare.net/rlmp