(Re)discovering the SPL - PHPWorld

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 Tech nalyze WWW.TECHANALYZE.IO
3. 3 Q: Have you ever used the SPL?
4. 4 Q: Have you ever used the SPL without going nuts?
5. 5 SPL Documentation
6. 5 SPL Documentation http://www.php.net/spl
10. ➡ Not enough documentation. 8
11. ➡ Not enough documentation. ➡ Very few examples. 8
12. ➡ Not enough documentation. ➡ Very few examples. ➡ Wrong / missing in some cases. 8
13. ➡ Interfaces ➡ Iterators ➡ Data structures ➡ Exceptions ➡ Miscellaneous functionality 9 Every SPL talk available:
14. 10 Don’t get scared! The SPL is awesomesauce!
15. 11 INTERFACES
16. 12 Traversable (not an “spl interface”)
18. ➡ Traversable cannot be implemented* 13
19. ➡ Traversable cannot be implemented* ➡ Traversable can be detected (instanceof). 13
20. ➡ Traversable cannot be implemented* ➡ Traversable can be detected (instanceof). ➡ foreach() detects traversable interfaces and does magic things. 13
21. 14 Iterator (still not an “spl interface”)
22. Userland interface to make an object traversable 15
23. 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 ) } 16 Iterator interface:
25. ➡ Iterator 17
26. ➡ Iterator ➡ FilterIterators 17
27. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together 17
28. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together ➡ IteratorAggregate 17
29. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together ➡ IteratorAggregate ➡ Is not an iterator, but HAS an iterator 17
30. 1 $dir = opendir("."); 2 while (($file = readdir($dir)) !== false) { 3 4 # Business logic happens here 5 print "file: $file\n"; 6 7 } 18
31. 1 $dir = opendir("."); 2 while (($file = readdir($dir)) !== false) { 3 4 # Business logic happens here 5 print "file: $file\n"; 6 7 } 18 awesome- app v1.0
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 } 19
33. ➡ Filter all MP3 and all JPG files. 20
34. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. 20
35. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. ➡ Do not filter at all. 20
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. 20
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. 20
39. ➡ How to test? (we can’t) 21
40. ➡ How to test? (we can’t) ➡ How to maintain? (we can’t) 21
41. ➡ How to test? (we can’t) ➡ How to maintain? (we can’t) ➡ How to reuse? (we can’t) 21
42. 1 $it = new DirectoryIterator("."); 2 foreach ($it as $fi) { 3 print "File: ".$fi->getPathname()."\n"; 4 } 22
43. 1 $it = new DirectoryIterator("."); 2 $it2 = new RegexIterator($it, "/\.mp3$/i"); 3 foreach ($it2 as $fi) { 4 print "File: ".$fi->getPathname()."\n"; 5 } 23
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, 5, 3); 5 6 foreach ($it4 as $fi) { 7 print "File: ".$fi->getPathname()."\n"; 8 } 24
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, 5, 3); 5 6 foreach ($it4 as $fi) { 7 print "File: ".$fi->getPathname()."\n"; 8 } 24
47. ✓ Reusable We can use iterators where ever we want. 25
48. ✓ Reusable We can use iterators where ever we want. ✓ Testable Iterators can be tested separately. 25
49. ✓ Reusable We can use iterators where ever we want. ✓ Testable Iterators can be tested separately. ✓ Maintainable No need to adapt our business logic. 25
50. 26 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); 27
52. 1 class myIterator implements \Iterator { 2 /* ... */ 3 } 4 5 $a = array(1, 2, 3); 6 $it = new myIterator($a); 7 8 print count($it); 1 27
53. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_elements); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 10 print count($it); 28
54. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_elements); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 10 print count($it); 5 28
55. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($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($it2); 29
56. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($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 29
57. 30 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 31
59. SPL Iterators 32 http://lxr.php.net/xref/PHP_5_5/ext/spl/internal/
62. ➡ IteratorIterator? 34
63. ➡ IteratorIterator? ➡ RecursiveIterator? 34
64. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? 34
65. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? ➡ RecursiveCallbackFilterIterator? 34
66. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? ➡ RecursiveCallbackFilterIterator? 34
67. 35 IteratorIterator
68. 36 Turns traversable “things” into an iterator
69. 37 1 $it = new myIterator(); 2 if ($it instanceof \IteratorAggregate) { 3 $it = $it->getIterator(); 4 } 5 $it2 = new \LimitIterator($it, 5, 10);
70. 38 1 $it = new myIterator(); 2 $it2 = new \IteratorIterator($it); 3 $it3 = new \LimitIterator($it2, 5, 10);
71. 39 Recursive*Iterator
72. 40 1 $it = new ArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 }
73. 40 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. 41 1 $it = new RecursiveArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 }
75. 41 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. 42 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. 42 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. 43 “Recursive” iterators add the POSSIBILITY to recursively iterate over data. You still need to implement it!
79. 44 RecursiveCallbackFilterIterator
80. ➡ Enables recursivity ➡ Is a filter iterator (does not necessarily return all the elements) ➡ Filters through a callback function. 45
81. 46 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! 47
83. 48 DATA STRUCTURES
84. 49 ➡ SplDoublyLinkedList ➡ SplStack ➡ SplQueue ➡ SplHeap ➡ SplMinHeap ➡ SplMaxHeap ➡ SplPriorityQueue ➡ SplFixedArray ➡ SplObjectStorage
85. 50 ➡ 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. 51 PubQuiz
87. 52 http://www.flickr.com/photos/sostark/26697448/
88. 52 http://www.flickr.com/photos/sostark/26697448/ SplStack
90. 53 SplQueue
91. 54 http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/
92. 54 http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/ Spl(Doubly)LinkedList
93. 55 http://www.flickr.com/photos/pediddle/54326823/
94. 55 http://www.flickr.com/photos/pediddle/54326823/ SplObjectStorage
96. 56 SplPriorityQueue
97. 57 http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg
98. 57 http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg SplHeap
99. 58 http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg
100. 58 http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg SplFixedArray
101. 59 ➡ Use wisely: ➡ Don’t use SplStack / SplQueue for random reads. ➡ Don’t use FixedArrays when you need speed boosts.
102. 60 EXCEPTIONS
103. ➡ BadFunctionCallException ➡ BadMethodCallException ➡ DomainException ➡ InvalidArgumentException ➡ LengthException ➡ LogicException ➡ OutOfBoundsException ➡ OutOfRangeException ➡ OverflowException ➡ RangeException ➡ RuntimeException ➡ UnderflowException ➡ UnexpectedValueException 61
104. ➡ BadFunctionCallException ➡ BadMethodCallException ➡ DomainException ➡ InvalidArgumentException ➡ LengthException ➡ OutOfRangeException 62 Logic Exceptions Runtime Exceptions ➡ OutOfBoundsException ➡ OverflowException ➡ RangeException ➡ UnderflowException ➡ UnexpectedValueException
105. 63 1 function foo($str) { 2 if ($str == "The Spanish Inquisition") { 3 throw new \UnexpectedValueException("Nobody expects ".$str); 4 } 5 /* ... */ 6 }
106. 64 1 function foo($str) { 2 if ($str == "The Spanish Inquisition") { 3 throw new \InvalidArgumentException("Nobody expects ".$str); 4 } 5 /* ... */ 6 } Logic, not runtime
107. 65 1 function foo($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. 66 Never throw “\Exception” Always catch “\Exception”
109. 67 MISC
110. ➡ SPL Autoloading ➡ SplFileInfo class ➡ Spl(Temp)FileObject ➡ ArrayObject ➡ SplObserver / SplSubject 68
111. 69 Autoloader
112. 70 spl_autoload_register("spl_autoload_call");
113. 70 spl_autoload_register("spl_autoload_call"); Throws logicException
114. 71 spl_autoload_unregister("spl_autoload_call");
115. 71 spl_autoload_unregister("spl_autoload_call"); - Removes ALL the autoloaders! - Destroys the autoload stack. - Set your house on fire.
116. 72 ArrayObject
117. 73 ArrayObjects are not objects that acts like arrays ArrayObjects are objects that acts like arrays
118. 74 1 $a = array("foo", "bar"); 2 $b = $a; 3 $b[] = "baz"; 4 5 print_r ($a); 6 print_r ($b);
119. 74 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. 75 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. 75 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. 76 How can we make using the SPL easier?
123. 77 ➡ 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)
125. ➡ Adaption of the SPL will only happen when developers can become familiar with it. 78
126. ➡ 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. 78
127. ➡ BLOG! ➡ Update documentation. ➡ Find the quirks, and maybe even solve them. 79
128. http://farm1.static.flickr.com/73/163450213_18478d3aa6_d.jpg 80
129. 81 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