(Re)discovering the SPL - Sweetlake 14

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 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
11. ➡ Not enough documentation. 8
12. ➡ Not enough documentation. ➡ Very few examples. 8
13. ➡ Not enough documentation. ➡ Very few examples. ➡ Wrong / missing in some cases. 8
14. ➡ Interfaces ➡ Iterators ➡ Data structures ➡ Exceptions ➡ Miscellaneous functionality 9 Every SPL talk available:
15. 10 Don’t get scared! The SPL is awesomesauce!
16. 11 INTERFACES
17. 12 Traversable (not an “spl interface”)
19. ➡ Traversable cannot be implemented. 13
20. ➡ Traversable cannot be implemented. ➡ Traversable can be detected (instanceof). 13
21. ➡ Traversable cannot be implemented. ➡ Traversable can be detected (instanceof). ➡ foreach() detects traversable interfaces and does magic things. 13
22. 14 Iterator (still not an “spl interface”)
23. Userland interface to make an object traversable 15
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 ) } 16 Iterator interface:
26. ➡ Iterator 17
27. ➡ Iterator ➡ FilterIterators 17
28. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together 17
29. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together ➡ IteratorAggregate 17
30. ➡ Iterator ➡ FilterIterators ➡ “Chains” iterators together ➡ IteratorAggregate ➡ Is not an iterator, but HAS an iterator 17
31. 18 1 <?php 2 3 $bookCollection = array( 4 new Book("50 shades of gray"), 5 new Book("The Hobbit"), 6 new Book("It"), 7 array( 8 new Book("Discworld: The colour of magic"), 9 new Book("Discworld: A light fantastic"), 10 ), 11 array( 12 new Book("Harry Potter and the deadly hallows"), 13 /* ... */ 14 ), 15 /* ... */ 16 ); 17 18 foreach ($bookCollection as $book) { 19 // Do something with a book, but how about book-series? 20 }
32. 19 1 <?php 2 3 $bookCollection = new BookCollection( 4 array( 5 new Book("50 shades of gray"), 6 new Book("The Hobbit"), 7 new Book("It"), 8 array('Discworld' => 9 new Book("The colour of magic"), 10 new Book("A light fantastic"), 11 ), 12 array('Harry Potter' => 13 new Book("Harry Potter and the deadly hallows"), 14 /* ... */ 15 ), 16 /* ... */ 17 )); 18 19 foreach ($bookCollection as $book) { 20 // Do something with all single books 21 } 22 23 foreach ($bookCollection->getSeries('Harry Potter')) { 24 // Do something with just one serie 25 } 26 27 $it = $bookCollection->getTopRatedBooks(); 28 $it2 = new LimitIterator($it, 0, 5); 29 foreach ($it2 as $book) { 30 // Do something with the top 5 31 } 32 33 $it = $bookCollection->getTopRatedBooks(); 34 $it2 = new RegexIterator($it, '/(gray|colour)/'); 35 foreach ($it2 as $book) { 36 // Do something with all books that have 'gray' or 'colour' in the title 37 }
33. 1 $dir = opendir("."); 2 while (($file = readdir($dir)) !== false) { 3 4 # Business logic happens here 5 print "file: $file\n"; 6 7 } 20
34. 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 } 21
35. ➡ Filter all MP3 and all JPG files. 22
36. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. 22
37. ➡ Filter all MP3 and all JPG files. ➡ Filter all MP3 files that are larger than 6MB. ➡ Do not filter at all. 22
38. ➡ 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. 22
39. ➡ 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. 22
41. ➡ How to test? (we can’t) 23
42. ➡ How to test? (we can’t) ➡ How to maintain? (we can’t) 23
43. ➡ How to test? (we can’t) ➡ How to maintain? (we can’t) ➡ How to reuse? (we can’t) 23
44. 1 $it = new DirectoryIterator("."); 2 foreach ($it as $fi) { 3 print "File: ".$fi->getPathname()."\n"; 4 } 24
45. 1 $it = new DirectoryIterator("."); 2 $it2 = new RegexIterator($it, "/\.mp3$/i"); 3 foreach ($it2 as $fi) { 4 print "File: ".$fi->getPathname()."\n"; 5 } 25
46. 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 } 26
47. 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 } 26
49. ✓ Reusable We can use iterators where ever we want. 27
50. ✓ Reusable We can use iterators where ever we want. ✓ Testable Iterators can be tested separately. 27
51. ✓ Reusable We can use iterators where ever we want. ✓ Testable Iterators can be tested separately. ✓ Maintainable No need to adapt our business logic. 27
52. 28 Countable (hurrah! An “spl interface”!)
53. 1 class myIterator implements \Iterator { 2 /* ... */ 3 } 4 5 $a = array(1, 2, 3); 6 $it = new myIterator($a); 7 8 print count($it); 29
54. 1 class myIterator implements \Iterator { 2 /* ... */ 3 } 4 5 $a = array(1, 2, 3); 6 $it = new myIterator($a); 7 8 print count($it); 1 29
55. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_elements); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 10 print count($it); 30
56. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($this->_elements); 4 } 5 } 6 7 $a = array(1, 2, 3, 4, 5); 8 $it = new myCountableIterator($a); 9 10 print count($it); 5 30
57. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($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($it2); 31
58. 1 class myCountableIterator extends myIterator implements Countable { 2 function count() { 3 return count($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 31
59. 32 ITERATORS
60. 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 33
61. SPL Iterators 34 http://lxr.php.net/xref/PHP_5_5/ext/spl/internal/
64. ➡ IteratorIterator? 36
65. ➡ IteratorIterator? ➡ RecursiveIterator? 36
66. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? 36
67. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? ➡ RecursiveCallbackFilterIterator? 36
68. ➡ IteratorIterator? ➡ RecursiveIterator? ➡ RecursiveIteratorIterator? ➡ RecursiveCallbackFilterIterator? 36
69. 37 IteratorIterator
70. 38 Turns traversable “things” into an iterator
71. 39 1 $it = new myIterator(); 2 if ($it instanceof \IteratorAggregate) { 3 $it = $it->getIterator(); 4 } 5 $it2 = new \LimitIterator($it, 5, 10);
72. 40 1 $it = new myIterator(); 2 $it2 = new \IteratorIterator($it); 3 $it3 = new \LimitIterator($it2, 5, 10);
73. 41 Recursive*Iterator
74. 42 1 $it = new ArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 }
75. 42 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
76. 43 1 $it = new RecursiveArrayIterator( 2 array("foo", "bar", array("qux", "wox"), "baz")); 3 4 foreach ($it as $v) { 5 print $v . "\n"; 6 }
77. 43 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
78. 44 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 }
79. 44 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
80. 45 “Recursive” iterators add the POSSIBILITY to recursively iterate over data. You still need to implement it!
81. 46 RecursiveCallbackFilterIterator
82. ➡ Enables recursivity ➡ Is a filter iterator (does not necessarily return all the elements) ➡ Filters through a callback function. 47
83. 48 SPL Iterators,..
84. ➡ 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! 49
85. 50 DATA STRUCTURES
86. 51 ➡ SplDoublyLinkedList ➡ SplStack ➡ SplQueue ➡ SplHeap ➡ SplMinHeap ➡ SplMaxHeap ➡ SplPriorityQueue ➡ SplFixedArray ➡ SplObjectStorage
87. 52 ➡ 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.
88. 53 PubQuiz
89. 54 http://www.flickr.com/photos/sostark/26697448/
90. 54 http://www.flickr.com/photos/sostark/26697448/ SplStack
92. 55 SplQueue
93. 56 http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/
94. 56 http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/ Spl(Doubly)LinkedList
95. 57 http://www.flickr.com/photos/pediddle/54326823/
96. 57 http://www.flickr.com/photos/pediddle/54326823/ SplObjectStorage
98. 58 SplPriorityQueue
99. 59 http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg
100. 59 http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg SplHeap
101. 60 http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg
102. 60 http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg SplFixedArray
103. 61 ➡ Use wisely: ➡ Don’t use SplStack / SplQueue for random reads. ➡ Don’t use FixedArrays when you need speed boosts.
104. 62 EXCEPTIONS
105. ➡ BadFunctionCallException ➡ BadMethodCallException ➡ DomainException ➡ InvalidArgumentException ➡ LengthException ➡ LogicException ➡ OutOfBoundsException ➡ OutOfRangeException ➡ OverflowException ➡ RangeException ➡ RuntimeException ➡ UnderflowException ➡ UnexpectedValueException 63
106. ➡ BadFunctionCallException ➡ BadMethodCallException ➡ DomainException ➡ InvalidArgumentException ➡ LengthException ➡ OutOfRangeException 64 Logic Exceptions Runtime Exceptions ➡ OutOfBoundsException ➡ OverflowException ➡ RangeException ➡ UnderflowException ➡ UnexpectedValueException
107. 65 1 function foo($str) { 2 if ($str == "The Spanish Inquisition") { 3 throw new \UnexpectedValueException("Nobody expects ".$str); 4 } 5 /* ... */ 6 }
108. 66 1 function foo($str) { 2 if ($str == "The Spanish Inquisition") { 3 throw new \InvalidArgumentException("Nobody expects ".$str); 4 } 5 /* ... */ 6 } Logic, not runtime
109. 67 1 function foo($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 }
110. 68 Never throw “\Exception” Always catch “\Exception”
111. 69 MISC
112. ➡ SPL Autoloading ➡ SplFileInfo class ➡ Spl(Temp)FileObject ➡ ArrayObject ➡ SplObserver / SplSubject 70
113. 71 Autoloader
114. 72 spl_autoload_register("spl_autoload_call");
115. 72 spl_autoload_register("spl_autoload_call"); Throws logicException
116. 73 spl_autoload_unregister("spl_autoload_call");
117. 73 spl_autoload_unregister("spl_autoload_call"); - Removes ALL the autoloaders! - Destroys the autoload stack. - Set your house on fire.
118. 74 ArrayObject
119. 75 ArrayObjects are not objects that acts like arrays ArrayObjects are objects that acts like arrays
120. 76 1 $a = array("foo", "bar"); 2 $b = $a; 3 $b[] = "baz"; 4 5 print_r ($a); 6 print_r ($b);
121. 76 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 )
122. 77 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));
123. 77 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 )
124. 78 How can we make using the SPL easier? http://noscope.com/photostream/albums/various/I_Want_To_Believe_01.jpg
125. 79 ➡ 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. 80
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. 80
129. ➡ BLOG! ➡ Update documentation. ➡ Find the quirks (and maybe even solve them). 81
130. http://farm1.static.flickr.com/73/163450213_18478d3aa6_d.jpg 82
131. 83 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