Escaping OOP boundaries

Most of developers are constantly teaching and discussing modern patterns, frameworks and libraries. But what if you think that you know almost everything about traditional OOP in PHP? I can bet that at some level of mastery you could notice that traditional object-oriented patterns do not solve all problems but introduce new questions instead. This is because OOP-way is not suited well for complex tasks.

Are you looking for the new food for thoughts about how such complex issues could be solved in PHP? For example how to make your existing method asynchronous just with one single word? Or how to reduce boilerplate code for feature toggles?

Join me and I will show you how to apply the most powerful aspect-oriented framework to escape from your existing OOP boundaries and teach you new patterns that can help you to keep your code clean.

Transcript

1. Escaping from OOP boundaries Alexander Lisachenko
2. About me: 2 lisachenko lisachenko
3. About me: ‣ Head of Web Development and Architecture at Alpari (RU) Forex Broker 2 lisachenko lisachenko
4. About me: ‣ Head of Web Development and Architecture at Alpari (RU) Forex Broker ‣ Have worked with computers since 7 years 2 lisachenko lisachenko
5. About me: ‣ Head of Web Development and Architecture at Alpari (RU) Forex Broker ‣ Have worked with computers since 7 years ‣ Clean code advocate, guru in the Enterprise Architecture 2 lisachenko lisachenko
6. About me: ‣ Head of Web Development and Architecture at Alpari (RU) Forex Broker ‣ Have worked with computers since 7 years ‣ Clean code advocate, guru in the Enterprise Architecture ‣ Author of the aspect-oriented framework Go! AOP 
 http://go.aopphp.com 2 lisachenko lisachenko
7. 3 Moscow PHP User Group
8. 3 Moscow PHP User Group
9. Agenda: 4
10. Agenda: ‣ Object-Oriented Paradigm boundaries 4
11. Agenda: ‣ Object-Oriented Paradigm boundaries ‣ Escaping from PHP boundaries. 4
12. Agenda: ‣ Object-Oriented Paradigm boundaries ‣ Escaping from PHP boundaries. ‣ Stream wrapper and filters. 4
13. Agenda: ‣ Object-Oriented Paradigm boundaries ‣ Escaping from PHP boundaries. ‣ Stream wrapper and filters. ‣ Cross-Cutting concerns. 4
14. Agenda: ‣ Object-Oriented Paradigm boundaries ‣ Escaping from PHP boundaries. ‣ Stream wrapper and filters. ‣ Cross-Cutting concerns. ‣ Aspect-Oriented Programming with Go! AOP 4
15. Agenda: ‣ Object-Oriented Paradigm boundaries ‣ Escaping from PHP boundaries. ‣ Stream wrapper and filters. ‣ Cross-Cutting concerns. ‣ Aspect-Oriented Programming with Go! AOP ‣ Hacking the PHP. Native structures and opcodes. 4
16. 5 OOP Boundaries
17. 6 Boundary 1: Open - Closed Principle
18. 6 Boundary 1: Open - Closed Principle
19. Class is Open for extension, but Closed for modification 7
20. 8 Final class prevents inheritance
21. 8 Final class prevents inheritance
22. 9 Final class prevents inheritance
23. 9 Final class prevents inheritance
24. 9 Final class prevents inheritance Fatal error: Class Child may not inherit from final class (Secret)
25. 10 Final method prevents overriding
26. 10 Final method prevents overriding
27. 11 Final method prevents overriding
28. 11 Final method prevents overriding
29. 11 Final method prevents overriding Fatal error: Cannot override final method Secret::test()
30. 11 Final method prevents overriding Fatal error: Cannot override final method Secret::test()
31. 12 Private modifier restricts access
32. 12 Private modifier restricts access
33. 13 Private modifier restricts access
34. 13 Private modifier restricts access
35. 14 Private modifier restricts access Uncaught Error: Call to private method Secret::test()
36. 15 Boundary 2: Immutable PHP structures
37. 15 Boundary 2: Immutable PHP structures
38. 16 PHP
39. 16 PHP Interpreter?
40. 16 PHP Interpreter? Compiler?
41. 16 PHP Interpreter? Compiler? BOTH!
42. 17 PHP Script
43. 17 PHP Script Execute
44. 17 PHP Script Parse Execute
45. 17 PHP Script Parse Execute Compile to OpCodes
46. 17 PHP Script Parse Execute Compile to OpCodes Execute(ZendEngine)
47. 17 PHP Script Parse Execute Compile to OpCodes Execute(ZendEngine) Output
48. 17 PHP Script Execute Execute(ZendEngine) Output Load OpCache <- Opcodes
49. Once compiled into Opcodes, code can not be changed in runtime 18
50. 19 OpCache:
51. 19 OpCache: +Fixed-size shared memory-block
52. 19 OpCache: +Fixed-size shared memory-block +Contains PHP binary structures
53. 19 OpCache: +Fixed-size shared memory-block +Contains PHP binary structures +Structures are immutable
54. 19 OpCache: +Fixed-size shared memory-block +Contains PHP binary structures +Structures are immutable +Append-only
55. 20 OpCache shared immutable data:
56. 20 OpCache shared immutable data: +File functions (HashTable)
57. 20 OpCache shared immutable data: +File functions (HashTable) +File classes (HashTable)
58. 20 OpCache shared immutable data: +File functions (HashTable) +File classes (HashTable) +File main OpArray
59. 20 OpCache shared immutable data: +File functions (HashTable) +File classes (HashTable) +File main OpArray +Interned strings and immutable arrays
60. 20 OpCache shared immutable data: +File functions (HashTable) +File classes (HashTable) +File main OpArray +Interned strings and immutable arrays +Meta-information (system_id, etc)
61. Shared immutable OpCache improves PHP performance a lot 21
62. 22 OpCache OOP restrictions:
63. 22 OpCache OOP restrictions: - Method could not be added/deleted or changed in runtime
64. 22 OpCache OOP restrictions: - Method could not be added/deleted or changed in runtime - Class, its parent, implemented interfaces and used traits are declared in compile-time, runtime API is not available
65. 22 OpCache OOP restrictions: - Method could not be added/deleted or changed in runtime - Class, its parent, implemented interfaces and used traits are declared in compile-time, runtime API is not available - Low-level access to the memory is restricted to prevents errors and memory leaks
66. 22 PS. Possible only with extensions like runkit, uopz, etc OpCache OOP restrictions: - Method could not be added/deleted or changed in runtime - Class, its parent, implemented interfaces and used traits are declared in compile-time, runtime API is not available - Low-level access to the memory is restricted to prevents errors and memory leaks
67. 23 Escaping from OOP Boundaries
68. Сan we mock/extend a final class or override a final method? 24
69. Сan we mock/extend a final class or override a final method? 24 Yes?
70. Сan we mock/extend a final class or override a final method? 24 Yes? No?
71. The simplest solution is to not mark classes or methods as final! 25
72. 26 Escape: uopz extension
73. «uopz is a black magic extension of the runkit-and-scary-stuff genre, intended to help with QA infrastructure. 27 Joe Watkins
74. 28 Mocking a final class - uopz extension
75. 28 Mocking a final class - uopz extension
76. 28 Mocking a final class - uopz extension
77. 29 Escape: Replace the «file» stream wrapper
78. 30 Idea:
79. 30 Idea: ‣ PHP uses internal «file» wrapper for includes
80. 30 Idea: ‣ PHP uses internal «file» wrapper for includes ‣ We can unregister the «file» handler via stream_wrapper_unregister(‘file’)
81. 30 Idea: ‣ PHP uses internal «file» wrapper for includes ‣ We can unregister the «file» handler via stream_wrapper_unregister(‘file’) ‣ Register our own file handler via stream_wrapper_register(‘file’, self::class)
82. 30 Idea: ‣ PHP uses internal «file» wrapper for includes ‣ We can unregister the «file» handler via stream_wrapper_unregister(‘file’) ‣ Register our own file handler via stream_wrapper_register(‘file’, self::class) ‣ Can hook into the PHP source file now!
83. 30 Idea: ‣ PHP uses internal «file» wrapper for includes ‣ We can unregister the «file» handler via stream_wrapper_unregister(‘file’) ‣ Register our own file handler via stream_wrapper_register(‘file’, self::class) ‣ Can hook into the PHP source file now! ‣ Tokenise code with token_get_all($source)
84. 30 Idea: ‣ PHP uses internal «file» wrapper for includes ‣ We can unregister the «file» handler via stream_wrapper_unregister(‘file’) ‣ Register our own file handler via stream_wrapper_register(‘file’, self::class) ‣ Can hook into the PHP source file now! ‣ Tokenise code with token_get_all($source) ‣ Transform this source (eg. remove final keyword)
85. 30 Idea: ‣ PHP uses internal «file» wrapper for includes ‣ We can unregister the «file» handler via stream_wrapper_unregister(‘file’) ‣ Register our own file handler via stream_wrapper_register(‘file’, self::class) ‣ Can hook into the PHP source file now! ‣ Tokenise code with token_get_all($source) ‣ Transform this source (eg. remove final keyword) ‣ Give it back to the PHP to compile
86. 31 dg/bypass-finals library composer show dg/bypass-finals name : dg/bypass-finals descrip. : Removes final keyword from source code on-the- fly and allows mocking of final methods and classes keywords : testing, phpunit, unit, mocking, finals versions : dev-master, v1.1.2, v1.1.1, v1.1.0, v1.0.1, v1.0 type : library
87. 32 Usage:
88. 32 Usage: You need to enable it before the classes you want to remove the final are loaded. So call it as soon as possible!
89. 32 Usage: You need to enable it before the classes you want to remove the final are loaded. So call it as soon as possible! PS. For additional details about PhpUnit integration, please read: https://www.tomasvotruba.cz/blog/2019/03/28/how-to-mock-final-classes-in-phpunit/
90. 33 antecedent/patchwork library composer show antecedent/patchwork name : antecedent/patchwork descrip. : Method redefinition (monkey-patching) functionality for PHP. keywords : aop, testing, aspect, runkit, redefinition, monkeypatching, interception versions : dev-master, 2.1.11, 2.1.10… type : library
91. Write tests for your PHP code, not code for the tests. 34
92. 35 Escape: Use PHP stream filters with includes
93. 36 Simple test file:
94. 36 Simple test file:
95. 37 Let’s craft our special include:
96. 37 Let’s craft our special include:
97. 38 It is become upper-cased:
98. 38 It is become upper-cased:
99. Idea: we can register our own stream filter via stream_filter_register() to process a source code. 39
100. Cross-cutting concerns
101. Cross-cutting concerns Data layer Service layer Controller layer
102. Cross-cutting concerns Data layer Service layer Controller layer Authorization Logging Caching Transaction Control
103. Cross-cutting concerns are aspects of a program that affect other domains. 41
104. Why? 42
105. Limitation of object-oriented representation of real life. 43
106. Joe Armstrong “…You wanted a banana but what you got was a gorilla holding the banana and the entire jungle” 44
107. Joe Armstrong “…You wanted a banana but what you got was a gorilla holding the banana and the entire jungle” 44
108. Example: 45
109. Example: 45 Implement an audit system that checks an access rights for each public method in all classes in our system and then logs this information into the security journal.
110. Example: 46
111. Example: 46
112. Authorization: 47
113. Authorization: 47
114. Logging and audit: 48
115. Logging and audit: 48
116. Error handling 49
117. Error handling 49
118. Code tangling 50
119. Code tangling 50
120. Code tangling 50
121. Code scattering (duplication) 51
122. Code scattering (duplication) 51
123. Code scattering (duplication) 51
124. Cross-cutting concerns 52
125. 53 Cross-cutting concerns
126. Aspect-Oriented Paradigm
127. Idea of AOP: extract cross-cutting concerns from general classes into the separate entities called aspects. 55
128. Authorization concern: 56
129. Authorization concern: 56
130. Authorization aspect: 57
131. Authorization aspect: 57
132. Authorization aspect: 57 Advice - event handler
133. Authorization aspect: 57 Pointcut - describes list of interesting events Advice - event handler
134. Authorization aspect: 57 Pointcut - describes list of interesting events Advice - event handler Joinpoint - defines an event object
135. 58 Aspect VS Event Listener
136. 58 Aspect VS Event Listener
137. 58 Aspect VS Event Listener
138. 58 Aspect VS Event Listener
139. 59 Advice types
140. 59 Advice types «Before» type
141. 59 Advice types «Before» type «After» type
142. 59 Advice types «Before» type «After» type «Around» type
143. With AOP we can subscribe to any method without changing original code. 60
144. 61 goaop/framework composer show goaop/framework name : goaop/framework descrip. : Framework for aspect-oriented programming in PHP. keywords : php, aop, library, aspect versions : 3.0.x-dev, 2.3.2,… type : library https://github.com/goaop/framework
145. How it works? 62
146. How it works? 62
147. 63 We use our trick with php://filter stream filter
148. 64 The composer class loader is replaced with a weaving proxy
149. 65 Lexical analysis and parsing of source code into the AST is performed (nikic/PHP-Parser)
150. 66 Static reflection is created from the AST (goaop/parser-reflection)
151. 66 Static reflection is created from the AST (goaop/parser-reflection)
152. 66 Static reflection is created from the AST (goaop/parser-reflection)
153. 66 Static reflection is created from the AST (goaop/parser-reflection)
154. 67 The original class is renamed and replaced with a new class with additional behavior; stored in the cache
155. 67 The original class is renamed and replaced with a new class with additional behavior; stored in the cache
156. 67 The original class is renamed and replaced with a new class with additional behavior; stored in the cache Same class name!
157. 67 The original class is renamed and replaced with a new class with additional behavior; stored in the cache Original class renamed Same class name!
158. 67 The original class is renamed and replaced with a new class with additional behavior; stored in the cache Original class renamed Overridden method Same class name!
159. 68 Deferred methods Runtime transformation of methods into deferred methods
160. 68 Deferred methods Runtime transformation of methods into deferred methods
161. 69 Example code
162. 69 Example code Some long service call
163. 69 Example code
164. 70 Idea: prevent execution of methods wrapping them into promises and run after the fastcgi_finish_request.
165. 71 Define an annotation-marker
166. 72 Define an aspect
167. 72 Define an aspect
168. 72 Define an aspect All methods with «Async» annotation
169. 72 Define an aspect Record each call with arguments
170. 72 Define an aspect Prevent execution of original method
171. 72 Define an aspect Return «our» value
172. 73 Define an aspect
173. 73 Define an aspect
174. 73 Define an aspect
175. 73 Define an aspect
176. 73 Define an aspect Finish FASTCGI Request
177. 73 Define an aspect Execute delayed methods
178. 74 Declare method as deferred
179. 74 Declare method as deferred
180. 74 Declare method as deferred Now it will be deferred
181. Hacking the PHP engine
182. Hacking the PHP engine
184. 77 FFI - Foreign Function Interface
185. 77 ‣ Available from PHP>=7.4 FFI - Foreign Function Interface
186. 77 ‣ Available from PHP>=7.4 ‣ Allows calling C functions FFI - Foreign Function Interface
187. 77 ‣ Available from PHP>=7.4 ‣ Allows calling C functions ‣ Allows using C data types from pure scripting language FFI - Foreign Function Interface
188. 77 ‣ Available from PHP>=7.4 ‣ Allows calling C functions ‣ Allows using C data types from pure scripting language ‣ Opens a way to write PHP extensions and bindings to C libraries in pure PHP FFI - Foreign Function Interface
189. 77 ‣ Available from PHP>=7.4 ‣ Allows calling C functions ‣ Allows using C data types from pure scripting language ‣ Opens a way to write PHP extensions and bindings to C libraries in pure PHP ‣ Headers can be preloaded during server startup FFI - Foreign Function Interface
190. 78 FFI - Foreign Function Interface
191. Idea: what if we use PHP’s FFI to access… 79
192. Idea: what if we use PHP’s FFI to access… 79 … PHP itself!
193. Idea: what if we use PHP’s FFI to access… 79 … PHP itself!
194. 80 lisachenko/z-engine composer show lisachenko/z-engine name : lisachenko/z-engine descrip. : Library that provides direct access to native PHP structures. versions : dev-master, 0.5.0,… type : library https://github.com/lisachenko/z-engine
195. 81 lisachenko/z-engine
196. 81 ‣ Build on top of PHP’s Reflection API, eg ReflectionClass, ReflectionMethod lisachenko/z-engine
197. 81 ‣ Build on top of PHP’s Reflection API, eg ReflectionClass, ReflectionMethod ‣ Provides low-level binding to PHP’s structures like zval, zend_class_entry, zend_function and much more… lisachenko/z-engine
198. 81 ‣ Build on top of PHP’s Reflection API, eg ReflectionClass, ReflectionMethod ‣ Provides low-level binding to PHP’s structures like zval, zend_class_entry, zend_function and much more… ‣ Manipulates PHP itself in runtime lisachenko/z-engine
199. 81 ‣ Build on top of PHP’s Reflection API, eg ReflectionClass, ReflectionMethod ‣ Provides low-level binding to PHP’s structures like zval, zend_class_entry, zend_function and much more… ‣ Manipulates PHP itself in runtime ‣ Expect memory leaks and segfaults! lisachenko/z-engine
200. 82 Un-final class
201. 82 Un-final class
202. 82 Un-final class
203. 82 Un-final class
204. 83 Serializable Closure class
205. 83 Serializable Closure class
206. 84 Serializable Closure class
207. 84 Serializable Closure class
208. 85 Custom Throwable objects
209. 86 Custom Throwable objects
210. 86 Custom Throwable objects
211. 87 Native assembly methods in PHP
212. 87 Native assembly methods in PHP
213. 88 First ever assembly method in PHP
214. 89 What to expect:
215. 89 ‣ API for userland PHP extensions What to expect:
216. 89 ‣ API for userland PHP extensions ‣ OpCode manipulation and transformation What to expect:
217. 89 ‣ API for userland PHP extensions ‣ OpCode manipulation and transformation ‣ Shared objects (will survive between requests) What to expect:
218. 89 ‣ API for userland PHP extensions ‣ OpCode manipulation and transformation ‣ Shared objects (will survive between requests) ‣ Native hooks for PHP callbacks What to expect:
219. 89 ‣ API for userland PHP extensions ‣ OpCode manipulation and transformation ‣ Shared objects (will survive between requests) ‣ Native hooks for PHP callbacks ‣ Much more :) What to expect:
222. Thank you for the attention! https://github.com/goaop https://github.com/lisachenko https://twitter.com/lisachenko Leave feedback at: https://joind.in/talk/310fd
223. Go! AOP: Plugin for the PhpStorm 92
224. Pointcut syntax highlighting, completion and analysis 93
225. Pointcut syntax highlighting, completion and analysis 93
226. Navigate to advice/advised elements 94
227. Navigate to advice/advised elements 94