(Re)discovering the SPL - Sweetlake 14

Transcript

1. 1
   Joshua Thijssen
   jaytaph
   (Re)discovering the SPL
   

   View Slide

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
   

   View Slide

3. 3
   Q: Have you ever used the SPL?
   

   View Slide

4. 4
   Q: Have you ever used the SPL
   without going nuts?
   

   View Slide

5. 5
   SPL Documentation
   

   View Slide

6. 5
   SPL Documentation
   http://www.php.net/spl
   

   View Slide

7. View Slide

8. View Slide

9. View Slide

10. View Slide

11. ➡ Not enough documentation.
    8
    

    View Slide

12. ➡ Not enough documentation.
    ➡ Very few examples.
    8
    

    View Slide

13. ➡ Not enough documentation.
    ➡ Very few examples.
    ➡ Wrong / missing in some cases.
    8
    

    View Slide

14. ➡ Interfaces
    ➡ Iterators
    ➡ Data structures
    ➡ Exceptions
    ➡ Miscellaneous functionality
    9
    Every SPL talk available:
    

    View Slide

15. 10
    Don’t get scared!
    The SPL is awesomesauce!
    

    View Slide

16. 11
    INTERFACES
    

    View Slide

17. 12
    Traversable
    (not an “spl interface”)
    

    View Slide

18. View Slide

19. ➡ Traversable cannot be implemented.
    13
    

    View Slide

20. ➡ Traversable cannot be implemented.
    ➡ Traversable can be detected (instanceof).
    13
    

    View Slide

21. ➡ Traversable cannot be implemented.
    ➡ Traversable can be detected (instanceof).
    ➡ foreach() detects traversable interfaces and
    does magic things.
    13
    

    View Slide

22. 14
    Iterator
    (still not an “spl interface”)
    

    View Slide

23. Userland interface to make
    an object traversable
    15
    

    View Slide

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:
    

    View Slide

25. View Slide

26. ➡ Iterator
    17
    

    View Slide

27. ➡ Iterator
    ➡ FilterIterators
    17
    

    View Slide

28. ➡ Iterator
    ➡ FilterIterators
    ➡ “Chains” iterators together
    17
    

    View Slide

29. ➡ Iterator
    ➡ FilterIterators
    ➡ “Chains” iterators together
    ➡ IteratorAggregate
    17
    

    View Slide

30. ➡ Iterator
    ➡ FilterIterators
    ➡ “Chains” iterators together
    ➡ IteratorAggregate
    ➡ Is not an iterator, but HAS an iterator
    17
    

    View Slide

31. 18
    1 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 }
    

    View Slide

32. 19
    1 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 }
    

    View Slide

33. 1 $dir = opendir(".");
    2 while (($file = readdir($dir)) !== false) {
    3
    4 # Business logic happens here
    5 print "file: $file\n";
    6
    7 }
    20
    

    View Slide

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
    

    View Slide

35. ➡ Filter all MP3 and all JPG files.
    22
    

    View Slide

36. ➡ Filter all MP3 and all JPG files.
    ➡ Filter all MP3 files that are larger than
    6MB.
    22
    

    View Slide

37. ➡ Filter all MP3 and all JPG files.
    ➡ Filter all MP3 files that are larger than
    6MB.
    ➡ Do not filter at all.
    22
    

    View Slide

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
    

    View Slide

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
    

    View Slide

40. View Slide

41. ➡ How to test? (we can’t)
    23
    

    View Slide

42. ➡ How to test? (we can’t)
    ➡ How to maintain? (we can’t)
    23
    

    View Slide

43. ➡ How to test? (we can’t)
    ➡ How to maintain? (we can’t)
    ➡ How to reuse? (we can’t)
    23
    

    View Slide

44. 1 $it = new DirectoryIterator(".");
    2 foreach ($it as $fi) {
    3 print "File: ".$fi->getPathname()."\n";
    4 }
    24
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

48. View Slide

49. ✓ Reusable
    We can use iterators where ever we want.
    27
    

    View Slide

50. ✓ Reusable
    We can use iterators where ever we want.
    ✓ Testable
    Iterators can be tested separately.
    27
    

    View Slide

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
    

    View Slide

52. 28
    Countable
    (hurrah! An “spl interface”!)
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

59. 32
    ITERATORS
    

    View Slide

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
    

    View Slide

61. SPL Iterators
    34
    http://lxr.php.net/xref/PHP_5_5/ext/spl/internal/
    

    View Slide

62. View Slide

63. View Slide

64. ➡ IteratorIterator?
    36
    

    View Slide

65. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    36
    

    View Slide

66. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    ➡ RecursiveIteratorIterator?
    36
    

    View Slide

67. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    ➡ RecursiveIteratorIterator?
    ➡ RecursiveCallbackFilterIterator?
    36
    

    View Slide

68. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    ➡ RecursiveIteratorIterator?
    ➡ RecursiveCallbackFilterIterator?
    36
    

    View Slide

69. 37
    IteratorIterator
    

    View Slide

70. 38
    Turns traversable “things” into an iterator
    

    View Slide

71. 39
    1 $it = new myIterator();
    2 if ($it instanceof \IteratorAggregate) {
    3 $it = $it->getIterator();
    4 }
    5 $it2 = new \LimitIterator($it, 5, 10);
    

    View Slide

72. 40
    1 $it = new myIterator();
    2 $it2 = new \IteratorIterator($it);
    3 $it3 = new \LimitIterator($it2, 5, 10);
    

    View Slide

73. 41
    Recursive*Iterator
    

    View Slide

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 }
    

    View Slide

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
    

    View Slide

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 }
    

    View Slide

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
    

    View Slide

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 }
    

    View Slide

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
    

    View Slide

80. 45
    “Recursive” iterators add the POSSIBILITY
    to recursively iterate over data.
    You still need to implement it!
    

    View Slide

81. 46
    RecursiveCallbackFilterIterator
    

    View Slide

82. ➡ Enables recursivity
    ➡ Is a filter iterator (does not necessarily
    return all the elements)
    ➡ Filters through a callback function.
    47
    

    View Slide

83. 48
    SPL Iterators,..
    

    View Slide

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
    

    View Slide

85. 50
    DATA STRUCTURES
    

    View Slide

86. 51
    ➡ SplDoublyLinkedList
    ➡ SplStack
    ➡ SplQueue
    ➡ SplHeap
    ➡ SplMinHeap
    ➡ SplMaxHeap
    ➡ SplPriorityQueue
    ➡ SplFixedArray
    ➡ SplObjectStorage
    

    View Slide

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.
    

    View Slide

88. 53
    PubQuiz
    

    View Slide

89. 54
    http://www.flickr.com/photos/sostark/26697448/
    

    View Slide

90. 54
    http://www.flickr.com/photos/sostark/26697448/
    SplStack
    

    View Slide

91. View Slide

92. 55
    SplQueue
    

    View Slide

93. 56
    http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/
    

    View Slide

94. 56
    http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/
    Spl(Doubly)LinkedList
    

    View Slide

95. 57
    http://www.flickr.com/photos/pediddle/54326823/
    

    View Slide

96. 57
    http://www.flickr.com/photos/pediddle/54326823/
    SplObjectStorage
    

    View Slide

97. View Slide

98. 58
    SplPriorityQueue
    

    View Slide

99. 59
    http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg
    

    View Slide

100. 59
     http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg
     SplHeap
     

     View Slide

101. 60
     http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg
     

     View Slide

102. 60
     http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg
     SplFixedArray
     

     View Slide

103. 61
     ➡ Use wisely:
     ➡ Don’t use SplStack / SplQueue for
     random reads.
     ➡ Don’t use FixedArrays when you need
     speed boosts.
     

     View Slide

104. 62
     EXCEPTIONS
     

     View Slide

105. ➡ BadFunctionCallException
     ➡ BadMethodCallException
     ➡ DomainException
     ➡ InvalidArgumentException
     ➡ LengthException
     ➡ LogicException
     ➡ OutOfBoundsException
     ➡ OutOfRangeException
     ➡ OverflowException
     ➡ RangeException
     ➡ RuntimeException
     ➡ UnderflowException
     ➡ UnexpectedValueException
     63
     

     View Slide

106. ➡ BadFunctionCallException
     ➡ BadMethodCallException
     ➡ DomainException
     ➡ InvalidArgumentException
     ➡ LengthException
     ➡ OutOfRangeException
     64
     Logic Exceptions Runtime Exceptions
     ➡ OutOfBoundsException
     ➡ OverflowException
     ➡ RangeException
     ➡ UnderflowException
     ➡ UnexpectedValueException
     

     View Slide

107. 65
     1 function foo($str) {
     2 if ($str == "The Spanish Inquisition") {
     3 throw new \UnexpectedValueException("Nobody expects ".$str);
     4 }
     5 /* ... */
     6 }
     

     View Slide

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
     

     View Slide

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 }
     

     View Slide

110. 68
     Never throw “\Exception”
     Always catch “\Exception”
     

     View Slide

111. 69
     MISC
     

     View Slide

112. ➡ SPL Autoloading
     ➡ SplFileInfo class
     ➡ Spl(Temp)FileObject
     ➡ ArrayObject
     ➡ SplObserver / SplSubject
     70
     

     View Slide

113. 71
     Autoloader
     

     View Slide

114. 72
     spl_autoload_register("spl_autoload_call");
     

     View Slide

115. 72
     spl_autoload_register("spl_autoload_call");
     Throws logicException
     

     View Slide

116. 73
     spl_autoload_unregister("spl_autoload_call");
     

     View Slide

117. 73
     spl_autoload_unregister("spl_autoload_call");
     - Removes ALL the autoloaders!
     - Destroys the autoload stack.
     - Set your house on fire.
     

     View Slide

118. 74
     ArrayObject
     

     View Slide

119. 75
     ArrayObjects are not objects that acts like arrays
     ArrayObjects are objects that acts like arrays
     

     View Slide

120. 76
     1 $a = array("foo", "bar");
     2 $b = $a;
     3 $b[] = "baz";
     4
     5 print_r ($a);
     6 print_r ($b);
     

     View Slide

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
     )
     

     View Slide

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));
     

     View Slide

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
     )
     

     View Slide

124. 78
     How can we make using the SPL easier?
     http://noscope.com/photostream/albums/various/I_Want_To_Believe_01.jpg
     

     View Slide

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)
     

     View Slide

126. View Slide

127. ➡ Adaption of the SPL will only happen
     when developers can become familiar
     with it.
     80
     

     View Slide

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
     

     View Slide

129. ➡ BLOG!
     ➡ Update documentation.
     ➡ Find the quirks (and maybe even solve
     them).
     81
     

     View Slide

130. http://farm1.static.flickr.com/73/163450213_18478d3aa6_d.jpg 82
     

     View Slide

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
     

     View Slide