Robert Lemke presented on using aspect-oriented programming (AOP) to create clean code at the T3CON10 conference in Frankfurt. AOP separates cross-cutting concerns, like logging and security, into aspects to improve modularity. FLOW3 is a PHP application framework that uses AOP to modularize these types of concerns apart from objects. Lemke demonstrated how to implement aspects in FLOW3 to intercept method calls and add behavior using advice.

1. Robert Lemke
Create Clean Code with Aspect-Oriented Programming
T3CON10 Frankfurt
/** Asp ect
*S ecu rity
*@ asp ect
*/ ityA spe ct {
cla s s Se cur olic ies;
tec ted $p
Samstag, 2. Oktober 2010
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2. Robert Lemke
chief 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
Samstag, 2. Oktober 2010

3. = PHP 5.3 Full Stack Application Framework
Samstag, 2. Oktober 2010

4. DI Dependency Injection DRY
YAA
OOP Object-Oriented Programming
YAGNI
AOP Aspect-Oriented Programming
CoC
MVC Model View Controller
POPO Plain Old PHP Object TDD
Samstag, 2. Oktober 2010

5. /**
* Creates a new post
*
* @param F3BlogDomainModelPost $newPost A fresh Post object which has not yet been
* added to the repository
* @return void
*/
public function createAction(F3BlogDomainModelPost $newPost) {
if ($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 F3FLOW3SecurityExceptionAccessDeniedException('Tried to create.');
}
$this->redirect('index');
}
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

6. /**
* Creates a new post
*
* @param F3BlogDomainModelPost $newPost A fresh Post object which has not yet been
* added to the repository
* @return void
*/
public function createAction(F3BlogDomainModelPost $newPost) {
if ($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 F3FLOW3SecurityExceptionAccessDeniedException('Tried to create.');
}
$this->redirect('index');
}
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

7. AOP
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

8. Aspect-Oriented Programming
programming paradigm
separates concerns to improve modularization
OOP modularizes concerns into objects
AOP modularizes cross-cutting concerns into aspects
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

9. /**
* Creates a new post
*
* @param F3BlogDomainModelPost $newPost A fresh Post object which has not yet been
* added to the repository
* @return void
*/
public function createAction(F3BlogDomainModelPost $newPost) {
$this->blog->addPost($newPost);
$this->flashMessageContainer->add('Your new post was created.');
$this->redirect('index');
}
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

10. Concerns?
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

11. Concerns
Separation 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 T3CON10 Frankfurt
Samstag, 2. Oktober 2010

12. Cross-Cutting Concerns
Logging
Security
Persistence
Global Business Logic
Dirty Hacks
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

13. We don't want infrastructure code
in our models.
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

14. We want to unit-test even
cross-cutting concerns
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

15. We want to centralize
security-related code
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

16. AOP Lingo
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

17. Aspect
Part of the application where cross-cutting concerns are implemented
In FLOW3 aspects are classes annotated with @aspect
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

18. Join Point
Is a single point in the call graph
Method Execution
Exception
Represents an event, not a location
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

19. Pointcut
A set of join points where advices could be executed
can be composed
can be named
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

20. Advice
Action to take at a join points defined by the point cut
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

21. DEMO
Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

22. Kinds of Advice
Advice types supported by FLOW3:
@before
@afterreturning
@afterthrowing
@after
@around
Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

23. Pointcut Designators
method(F3MyPackageMyClass->myMethod())
class(F3MyPackageMyClass)
within(F3MyPackageMyInterface)
classTaggedWith(someTag)
methodTaggedWith(anotherTag)
setting(Demo.Stuff.SomeSetting = "yeah, do it")
filter(F3MyPackageMyCustomFilterImplementation)
fi
Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

24. Runtime Evaluations
evaluate(coffee.kind == "Arabica")
Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

25. Compound Pointcuts
! /**
! * @around method(.*Controller->(new|create|edit|update|delete)Action()) &&
!methodTaggedWith(anybodyMayAccessThis)
! */
! public function interceptMethodCalls($joinPoint) {
...
}
Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

26. DEMO
Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

27. FLOW3's AOP implementation
based 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 to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

28. Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

29. Inspiring people to
Hitchhiker's Guide to FLOW3 share
Samstag, 2. Oktober 2010

30. Progress
FLOW3 1.0.0
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

31. Further Reading
FLOW3 Website
http://flow3.typo3.org
FLOW3 Download
http://flow3.typo3.org/download
git://git.typo3.org/FLOW3/Distributions/Base.git
TYPO3 Forge
http://forge.typo3.org
Further Reading
http://flow3.typo3.org/about/principles/further-reading
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

32. Questions
Email: robert@typo3.org
Blog: http://robertlemke.de/blog
Twitter: @t3rob
Slides: http://slideshare.net/rlmp
Create Clean Code with AOP T3CON10 Frankfurt
Samstag, 2. Oktober 2010

33. Samstag, 2. Oktober 2010