Aspect Oriented Programming in PHP

AOP is a programming paradigm that aims to separate supporting functionality from the business logic. In this talk I'll explain in more detail what AOP is, how we can apply it in PHP, and what kind of solutions are currently available.

Link to Go! AOP: http://go.aopphp.com/
Link to PHP-AOP: http://pecl.php.net/package/AOP

Transcript

1. ASPECT ORIENTED PROGRAMMING IN PHP I’m Frank van den Brink. I’m a Pragmatist. @fvdb
2. TODAY’S AGENDA
3. THE ORIGINS
4. THE ORIGINS HOW IT WORKS
5. THE ORIGINS HOW IT WORKS USING IT IN PHP
6. THE ORIGINS
7. Source: http://siliconvalley.sutromedia.com/xerox-parc.html
8. class SecretService { public function getSecret($id) { // Check access if (!$this->isAllowedToAccess($id)) { throw new AccessDeniedException('You cannot do this!'); } // Get the secret $secret = $this->storage->getById($id); // Log that someone’s fetching the secret $this->logger->info('Secret accessed!'); return $secret; } }
9. SEPARATION OF CONCERNS Hürsch, Lopes - 1995
10. Programming intertwined code is hard and complex since all concerns have to be dealt with at the same time and at the same level. Source: Separation of Concerns - Hürsch, Lopes - 1995
11. Programming intertwined code is hard and complex since all concerns have to be dealt with at the same time and at the same level. The extended programming language provides no adequate abstraction of concerns at the implementation level. Source: Separation of Concerns - Hürsch, Lopes - 1995
12. Intertwined code is hard to understand because of the above lack of abstraction. Source: Separation of Concerns - Hürsch, Lopes - 1995
13. Commingled code is hard to maintain and modify because the concerns are strongly coupled. Source: Separation of Concerns - Hürsch, Lopes - 1995
14. The intertwined code gives rise to inheritance anomalies due to the strong coupling of different concerns. Source: Separation of Concerns - Hürsch, Lopes - 1995
15. The intertwined code gives rise to inheritance anomalies due to the strong coupling of different concerns. It becomes impossible to redefine a method implementation or the commingled special concern in a subclass without redefining both. Source: Separation of Concerns - Hürsch, Lopes - 1995
16. class SecretService { public function getSecret($id) { // Check access if (!$this->isAllowedToAccess($id)) { throw new AccessDeniedException('You cannot do this!'); } // Get the secret $secret = $this->storage->getById($id); // Log that someone’s fetching the secret $this->logger->info('Secret accessed!'); return $secret; } }
17. class SecretService { public function getSecret($id) { return $this->storage->getById($id); } }
18. META-LEVEL PROGRAMMING ADAPTIVE PROGRAMMING COMPOSITION FILTERS
19. RG AML ETCML DJ DJAVA
20. AspectJ
21. HOW IT WORKS
22. class Awesome { } 89 50 4e 47 0d 0a 1a fe c3 1b 6c 88 COMPILER
23. class SecretService { public function getSecret($id) { return $this->storage->getById($id); } }
24. class SecretService { public function getSecret($id) { return $this->storage->getById($id); } } class AuthorizationAspect { public function checkAccessBeforeGetSecret($id) { if (!$this->isAllowedToAccess($id)) { throw new AccessDeniedException('You cannot do this!'); } } }
25. class SecretService { public function getSecret($id) { return $this->storage->getById($id); } } class AuthorizationAspect { public function checkAccessBeforeGetSecret($id) { if (!$this->isAllowedToAccess($id)) { throw new AccessDeniedException('You cannot do this!'); } } } class LoggingAspect { public function logAfterGetSecret($id) { $this->logger->info('Secret accessed!'); } }
26. class SecretService { public function getSecret($id) { // Check access if (!$this->isAllowedToAccess($id)) { throw new AccessDeniedException('You cannot do this!'); } // Get the secret $secret = $this->storage->getById($id); // Log that someone’s fetching the secret $this->logger->info('Secret accessed!'); return $secret; } }
27. CROSS CUTTING CONCERN
30. CROSS CUTTING CONCERN
31. CROSS CUTTING CONCERN ASPECTS
32. CROSS CUTTING CONCERN ASPECTS ADVICE
33. class LoggingAspect { public function logAfterGetSecret($id) { $this->logger->info('Secret accessed!'); } }
34. CROSS CUTTING CONCERN ASPECTS ADVICE
35. CROSS CUTTING CONCERN ASPECTS ADVICE JOIN POINTS
36. class SecretService { public function getSecret($id) { return $this->storage->getById($id); } } BEFORE METHOD CALL
37. class SecretService { public function getSecret($id) { return $this->storage->getById($id); } } AFTER METHOD CALL
38. class SecretService { public function getSecret($id) { return $this->storage->getById($id); } } AROUND METHOD CALL
39. CROSS CUTTING CONCERN ASPECTS ADVICE JOIN POINTS
40. CROSS CUTTING CONCERN ASPECTS ADVICE JOIN POINTS POINT CUTS
41. Before( execution( public SecretService->*(*) ) )
42. CROSS CUTTING CONCERN ASPECTS ADVICE JOIN POINTS POINT CUTS
43. CROSS CUTTING CONCERN ASPECTS ADVICE JOIN POINTS POINT CUTS WEAVING
44. WEAVING
45. WEAVING
46. WEAVING
47. WEAVING
48. WEAVING
49. CROSS CUTTING CONCERN ASPECTS ADVICE JOIN POINTS POINT CUTS WEAVING
50. USING IT IN PHP
51. CAN YOU USE IT IN PHP?
52. X X X X X O O O O
53. X X X X X O O O O O
54. AOP-PHP Flow AOP Go! AOP JMSAopBundle
55. AOP-PHP Flow AOP Go! AOP JMSAopBundle ext lib lib lib
56. AOP-PHP Flow AOP Go! AOP JMSAopBundle ext lib lib lib
57. AOP-PHP Flow AOP Go! AOP JMSAopBundle ext lib lib lib
58. AOP-PHP
59. function logAfterGetSecret() { $this->logger->info('Secret accessed!'); } aop_add_after( 'SecretService->getSecret()', 'logAfterGetSecret' );
60. Go! AOP
61. new Example\Foobar Autoloader Weaver
62. new Example\Foobar Autoloader Weaver
63. new Example\Foobar Autoloader Weaver
64. new Example\Foobar Autoloader Weaver
65. new Example\Foobar Autoloader Weaver
66. new Example\Foobar Autoloader Weaver
67. new Example\Foobar Autoloader Weaver
68. new Example\Foobar Autoloader Weaver
69. class LoggingAspect implements Aspect { /** * @After("execution(public SecretService->getSecret(*))") */ public function logAfterGetSecret(MethodInvocation $invocation) { $args = $invocation->getArguments(); $this->logger->info('Secret ' . $args[0] . ' accessed!'); } }
70. class CachingAspect implements Aspect { /** * @Around("execution(public SecretService->getSecret(*))") */ public function cacheGetSecret(MethodInvocation $invocation) { $args = $invocation->getArguments(); if ($this->cache->has($args[0])) { return $this->cache->get($args[0]); } $secret = $invocation->proceed(); $this->cache->set($args[0], $secret); return $secret; } }
71. SHOULD YOU USE AOP?
72. PERFORMANCE
73. PERFORMANCE CLARITY
74. PERFORMANCE CLARITY DON’T GO NUTS
75. AOP ALL THE THINGS!
76. MERCI BIEN @fvdb http://about.me/fvdb http://speakerdeck.com/u/fvdb