(Re)discovering the SPL

Transcript

1. 1 Joshua Thijssen jaytaph (Re)discovering the SPL
2. 2 Joshua Thijssen Freelance consultant and trainer @ TechAdemy Founder of TechAnalyze.io Founder of the Dutch Web Alliance Blog: http://adayinthelifeof.nl Email: jthijssen@noxlogic.nl Twitter: @jaytaph
3. 3 Tech nalyze WWW.TECHANALYZE.IO Your free credit voucher code: ohthehorror
4. 4 Q: Have you ever used the SPL?
5. 5 Q: Have you ever used the SPL without going nuts?
6. 6 SPL Documentation
7. 6 SPL Documentation http://www.php.net/spl
11. ➡ Not enough documentation. 9
12. ➡ Not enough documentation. ➡ Very few examples. 9
13. ➡ Not enough documentation. ➡ Very few examples. ➡ Wrong / missing in some cases. 9
14. ➡ Interfaces ➡ Iterators ➡ Data structures ➡ Exceptions ➡ Miscellaneous functionality 10
15. 11 Don’t get scared! The SPL is awesomesauce!
16. 12 INTERFACES
17. 13 Traversable (not an “spl interface”)
19. ➡ Traversable cannot be implemented* 14
20. ➡ Traversable cannot be implemented* ➡ Traversable can be detected (instanceof). 14
21. ➡ Traversable cannot be implemented* ➡ Traversable can be detected (instanceof). ➡ foreach() detects traversable interfaces and does magic things. 14
22. 15 Iterator (still not an “spl interface”)
23. Userland interface to make an object traversable 16
24. Iterator extends Traversable { /* Methods */ abstract public mixed current ( void ) abstract public scalar key ( void ) abstract public void next ( void ) abstract public void rewind ( void ) abstract public boolean valid ( void ) } 17 Iterator interface:
26. ➡ Iterator 18
27. ➡ Iterator ➡ FilterIterators 18
28. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together 18
29. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together ➡ IteratorAggregate 18
30. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together ➡ IteratorAggregate ➡ Is not an iterator, but HAS an iterator 18
31. 1 $dir = opendir("."); 2 while (($file = readdir($dir)) !== false) { 3 4 # Business logic happens here 5 print "file: $file\n"; 6 7 } 19
32. 1 $dir = opendir("."); 2 while (($file = readdir($dir)) !== false) { 3 4 # hack: filter only mp3 files 5 if (! preg_match('|\.mp3$|i', $file)) { 6 continue; 7 } 8 9 # Business logic happens here 10 print "file: $file\n"; 11 } 20
33. ➡ Filter all MP3 and all JPG files. 21
34. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. 21
35. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. ➡ Do not filter at all. 21
36. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. ➡ Do not filter at all. ➡ Search sub-directories as well. 21
37. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. ➡ Do not filter at all. ➡ Search sub-directories as well. ➡ Search multiple directories. 21
39. ➡ How to test? (we can’t) 22
40. ➡ How to test? (we can’t) ➡ How to maintain? (we can’t) 22
41. ➡ How to test? (we can’t) ➡ How to maintain? (we can’t) ➡ How to reuse? (we can’t) 22
42. 1 $it = new DirectoryIterator("."); 2 foreach ($it as $fi) { 3 print "File: ".$fi->getPathname()."\n"; 4 } 23
43. 1 $it = new DirectoryIterator("."); 2 $it2 = new RegexIterator($it, "/\.mp3$/i"); 3 foreach ($it2 as $fi) { 4 print "File: ".$fi->getPathname()."\n"; 5 } 24
44. 1 $it = new DirectoryIterator("."); 2 $it2 = new RegexIterator($it, "/\.mp3$/i"); 3 $it3 = new FilesizeIterator($it2, 0, 6 * 1024 * 1024); 4 $it4 = new LimitIterator($it3, 10, 5); 5 6 foreach ($it4 as $fi) { 7 print "File: ".$fi->getPathname()."\n"; 8 } 25
45. 1 $it = new DirectoryIterator("."); 2 $it2 = new RegexIterator($it, "/\.mp3$/i"); 3 $it3 = new FilesizeIterator($it2, 0, 6 * 1024 * 1024); 4 $it4 = new LimitIterator($it3, 10, 5); 5 6 foreach ($it4 as $fi) { 7 print "File: ".$fi->getPathname()."\n"; 8 } 25
47. ✓ Reusable We can use iterators where ever we want. 26
48. ✓ Reusable We can use iterators where ever we want. ✓ Testable Iterators can be tested separately. 26
49. ✓ Reusable We can use iterators where ever we want. ✓ Testable Iterators can be tested separately. ✓ Maintainable No need to adapt our business logic. 26
50. 27 Countable (hurrah! An “spl interface”!)
51. 1 class myIterator implements \Iterator { 2 /* ... */ 3 } 4 5 $a = array(1, 2, 3); 6 $it = new myIterator($a); 7 8 print count($it); 28
52. 1 class myIterator implements \Iterator { 2 /* ... */ 3 } 4 5 $a = array(1, 2, 3); 6 $it = new myIterator($a); 7 8 print count($it); 1 28
53. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_elements); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 10 print count($it); 29
54. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_elements); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 10 print count($it); 5 29
55. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_arr); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 $it2 = new limitIterator($it, 0, 3); 10 11 print count($it2); 30
56. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_arr); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 $it2 = new limitIterator($it, 0, 3); 10 11 print count($it2); 1 30
57. 31 ITERATORS
58. SPL Iterators ➡ AppendIterator ➡ ArrayIterator ➡ CachingIterator ➡ CallbackFilterIterator ➡ DirectoryIterator ➡ EmptyIterator ➡ FilesystemIterator ➡ FilterIterator ➡ GlobIterator ➡ InfiniteIterator ➡ IteratorIterator ➡ LimitIterator ➡ MultipleIterator ➡ NoRewindIterator ➡ ParentIterator ➡ RecursiveArrayIterator ➡ RecursiveCachingIterator ➡ RecursiveCallbackFilterIterator ➡ RecursiveDirectoryIterator ➡ RecursiveFilterIterator ➡ RecursiveIteratorIterator ➡ RecursiveRegexIterator ➡ RecursiveTreeIterator ➡ RegexIterator ➡ SimpleXMLIterator 32
59. SPL Iterators 33 http://lxr.php.net/xref/PHP_5_5/ext/spl/internal/
62. ➡ IteratorIterator? 35
63. ➡ IteratorIterator? ➡ RecursiveIterator? 35
64. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? 35
65. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? ➡ RecursiveCallbackFilterIterator? 35
66. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? ➡ RecursiveCallbackFilterIterator? 35
67. 36 IteratorIterator
68. 37 Turns traversable “things” into an iterator
69. 38 1 $it = new myIterator(); 2 if ($it instanceof \IteratorAggregate) { 3 $it = $it->getIterator(); 4 } 5 $it2 = new \LimitIterator($it, 5, 10);
70. 39 1 $it = new myIterator(); 2 $it2 = new \IteratorIterator($it); 3 $it3 = new \LimitIterator($it2, 5, 10);
71. 40 Recursive*Iterator
72. 41 1 $it = new ArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 }
73. 41 1 $it = new ArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 } foo bar Array baz
74. 42 1 $it = new RecursiveArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 }
75. 42 1 $it = new RecursiveArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 } foo bar Array baz
76. 43 1 $it = new RecursiveArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 $it2 = new RecursiveIteratorIterator($it); 4 5 foreach ($it2 as $v) { 6 print $v . "\n"; 7 }
77. 43 1 $it = new RecursiveArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 $it2 = new RecursiveIteratorIterator($it); 4 5 foreach ($it2 as $v) { 6 print $v . "\n"; 7 } foo bar qux wox baz
78. 44 “Recursive” iterators add the POSSIBILITY to recursively iterate over data. You still need to implement it!
79. 45 RecursiveCallbackFilterIterator
80. ➡ Enables recursivity ➡ Is a filter iterator (does not necessarily return all the elements) ➡ Filters through a callback function. 46
81. 47 SPL Iterators,..
82. ➡ It has “quirks” that are easily solvable (but breaks BC) ➡ Documentation is not always up to date. ➡ Naming is VERY confusing (caching iterator, recursiveIterator, seekableIterator) ➡ But the iterators are worth it! 48
83. 49 DATA STRUCTURES
84. 50 ➡ SplDoublyLinkedList ➡ SplStack ➡ SplQueue ➡ SplHeap ➡ SplMinHeap ➡ SplMaxHeap ➡ SplPriorityQueue ➡ SplFixedArray ➡ SplObjectStorage
85. 51 ➡ Every data structure has its strength and weaknesses. ➡ Big-Oh O(1), O(n), O(log n) etc... ➡ Balance between time (CPU) and space (memory) ➡ PHP arrays are quite good! ➡ But sometimes other data structures are better.
86. 52 PubQuiz
87. 53 http://www.flickr.com/photos/sostark/26697448/
88. 53 http://www.flickr.com/photos/sostark/26697448/ SplStack
90. 54 SplQueue
91. 55 http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/
92. 55 http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/ Spl(Doubly)LinkedList
93. 56 http://www.flickr.com/photos/pediddle/54326823/
94. 56 http://www.flickr.com/photos/pediddle/54326823/ SplObjectStorage
96. 57 SplPriorityQueue
97. 58 http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg
98. 58 http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg SplHeap
99. 59 http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg
100. 59 http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg SplFixedArray
101. 60 ➡ Use wisely: ➡ Don’t use SplStack / SplQueue for random reads. ➡ Don’t use FixedArrays when you need speed boosts.
102. 61 EXCEPTIONS
103. ➡ BadFunctionCallException ➡ BadMethodCallException ➡ DomainException ➡ InvalidArgumentException ➡ LengthException ➡ LogicException ➡ OutOfBoundsException ➡ OutOfRangeException ➡ OverflowException ➡ RangeException ➡ RuntimeException ➡ UnderflowException ➡ UnexpectedValueException 62
104. ➡ BadFunctionCallException ➡ BadMethodCallException ➡ DomainException ➡ InvalidArgumentException ➡ LengthException ➡ OutOfRangeException 63 Logic Exceptions Runtime Exceptions ➡ OutOfBoundsException ➡ OverflowException ➡ RangeException ➡ UnderflowException ➡ UnexpectedValueException
105. 64 1 function foo($str) { 2 if ($str == "The Spanish Inquisition") { 3 throw new \UnexpectedValueException("Nobody expects ".$str); 4 } 5 /* ... */ 6 }
106. 65 1 function foo($str) { 2 if ($str == "The Spanish Inquisition") { 3 throw new \InvalidArgumentException("Nobody expects ".$str); 4 } 5 /* ... */ 6 } Logic, not runtime
107. 66 1 function foo($str) { 2 if ($str == "The Spanish Inquisition") { 3 /* logic */ 4 throw new \InvalidArgumentException("Nobody expects ".$str); 5 } 6 7 try { 8 $this->getDatabase()->saveRecord($str); 9 } catch (\RuntimeException $e) { 10 /* We could try again here */ 11 } catch (\Exception $e) { 12 /* Sorry, something else occurred. */ 13 } 14 }
108. 67 Never throw “\Exception” Always catch “\Exception”
109. 68 MISC
110. ➡ SPL Autoloading ➡ SplFileInfo class ➡ Spl(Temp)FileObject ➡ ArrayObject ➡ SplObserver / SplSubject 69
111. 70 Autoloader
112. 71 spl_autoload_register("spl_autoload_call");
113. 71 spl_autoload_register("spl_autoload_call"); Throws logicException
114. 72 spl_autoload_unregister("spl_autoload_call");
115. 72 spl_autoload_unregister("spl_autoload_call"); - Removes ALL the autoloaders! - Destroys the autoload stack. - Set your house on fire.
116. 73 ArrayObject
117. 74 ArrayObjects are not objects that acts like arrays ArrayObjects are objects that acts like arrays
118. 75 1 $a = array("foo", "bar"); 2 $b = $a; 3 $b[] = "baz"; 4 5 print_r ($a); 6 print_r ($b);
119. 75 1 $a = array("foo", "bar"); 2 $b = $a; 3 $b[] = "baz"; 4 5 print_r ($a); 6 print_r ($b); Array ( [0] => foo [1] => bar ) Array ( [0] => foo [1] => bar [2] => baz )
120. 76 1 $a = new ArrayObject(); 2 $a[] = "foo"; 3 $a[] = "bar"; 4 5 $b = $a; 6 $b[] = "baz"; 7 8 print_r (iterator_to_array($a)); 9 print_r (iterator_to_array($b));
121. 76 1 $a = new ArrayObject(); 2 $a[] = "foo"; 3 $a[] = "bar"; 4 5 $b = $a; 6 $b[] = "baz"; 7 8 print_r (iterator_to_array($a)); 9 print_r (iterator_to_array($b)); Array ( [0] => foo [1] => bar [2] => baz ) Array ( [0] => foo [1] => bar [2] => baz )
122. 77 How about the SPL & Drupal ?
123. ➡ Not all that bad! ➡ Makes heavy use of iterators ➡ Exceptions are ok ➡ Too many new \Exceptions() (129) ➡ Datastructures not really 78
124. 79 How can we make using the SPL easier?
125. 80 ➡ The (first and only) book about the SPL. ➡ Written by me (so you know it’s good :P) ➡ Fixes the documentation problem of the SPL (or a wobbly table)
127. ➡ Adaption of the SPL will only happen when developers can become familiar with it. 81
128. ➡ Adaption of the SPL will only happen when developers can become familiar with it. ➡ There is currently no real way to familiarize yourself with the SPL. 81
129. ➡ BLOG! ➡ Update documentation. ➡ Find the quirks, and maybe even solve them. 82
130. http://farm1.static.flickr.com/73/163450213_18478d3aa6_d.jpg 83
131. 84 Find me on twitter: @jaytaph Find me for development and training: www.noxlogic.nl Find me on email: jthijssen@noxlogic.nl Find me for blogs: www.adayinthelifeof.nl Symfony2 Webinar