(Re)discovering the SPL - PHPWorld

Transcript

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

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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
   

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

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

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5. 5
   SPL Documentation
   

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

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10. ➡ Not enough documentation.
    8
    

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

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

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

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14. 10
    Don’t get scared!
    The SPL is awesomesauce!
    

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15. 11
    INTERFACES
    

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16. 12
    Traversable
    (not an “spl interface”)
    

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18. ➡ Traversable cannot be implemented*
    13
    

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

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

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21. 14
    Iterator
    (still not an “spl interface”)
    

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22. Userland interface to make
    an object traversable
    15
    

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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:
    

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25. ➡ Iterator
    17
    

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26. ➡ Iterator
    ➡ FilterIterators
    17
    

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

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

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

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30. 1 $dir = opendir(".");
    2 while (($file = readdir($dir)) !== false) {
    3
    4 # Business logic happens here
    5 print "file: $file\n";
    6
    7 }
    18
    

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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
    

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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
    

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33. ➡ Filter all MP3 and all JPG files.
    20
    

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34. ➡ Filter all MP3 and all JPG files.
    ➡ Filter all MP3 files that are larger than 6MB.
    20
    

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35. ➡ Filter all MP3 and all JPG files.
    ➡ Filter all MP3 files that are larger than 6MB.
    ➡ Do not filter at all.
    20
    

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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
    

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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
    

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39. ➡ How to test? (we can’t)
    21
    

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40. ➡ How to test? (we can’t)
    ➡ How to maintain? (we can’t)
    21
    

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41. ➡ How to test? (we can’t)
    ➡ How to maintain? (we can’t)
    ➡ How to reuse? (we can’t)
    21
    

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42. 1 $it = new DirectoryIterator(".");
    2 foreach ($it as $fi) {
    3 print "File: ".$fi->getPathname()."\n";
    4 }
    22
    

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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
    

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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
    

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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
    

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47. ✓ Reusable
    We can use iterators where ever we want.
    25
    

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48. ✓ Reusable
    We can use iterators where ever we want.
    ✓ Testable
    Iterators can be tested separately.
    25
    

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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
    

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50. 26
    Countable
    (hurrah! An “spl interface”!)
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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57. 30
    ITERATORS
    

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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
    

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59. SPL Iterators
    32
    http://lxr.php.net/xref/PHP_5_5/ext/spl/internal/
    

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61. View Slide

62. ➡ IteratorIterator?
    34
    

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63. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    34
    

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64. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    ➡ RecursiveIteratorIterator?
    34
    

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65. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    ➡ RecursiveIteratorIterator?
    ➡ RecursiveCallbackFilterIterator?
    34
    

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66. ➡ IteratorIterator?
    ➡ RecursiveIterator?
    ➡ RecursiveIteratorIterator?
    ➡ RecursiveCallbackFilterIterator?
    34
    

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67. 35
    IteratorIterator
    

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68. 36
    Turns traversable “things” into an iterator
    

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69. 37
    1 $it = new myIterator();
    2 if ($it instanceof \IteratorAggregate) {
    3 $it = $it->getIterator();
    4 }
    5 $it2 = new \LimitIterator($it, 5, 10);
    

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70. 38
    1 $it = new myIterator();
    2 $it2 = new \IteratorIterator($it);
    3 $it3 = new \LimitIterator($it2, 5, 10);
    

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71. 39
    Recursive*Iterator
    

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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 }
    

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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
    

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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 }
    

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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
    

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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 }
    

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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
    

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78. 43
    “Recursive” iterators add the POSSIBILITY
    to recursively iterate over data.
    You still need to implement it!
    

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79. 44
    RecursiveCallbackFilterIterator
    

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80. ➡ Enables recursivity
    ➡ Is a filter iterator (does not necessarily
    return all the elements)
    ➡ Filters through a callback function.
    45
    

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81. 46
    SPL Iterators,..
    

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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
    

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83. 48
    DATA STRUCTURES
    

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84. 49
    ➡ SplDoublyLinkedList
    ➡ SplStack
    ➡ SplQueue
    ➡ SplHeap
    ➡ SplMinHeap
    ➡ SplMaxHeap
    ➡ SplPriorityQueue
    ➡ SplFixedArray
    ➡ SplObjectStorage
    

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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.
    

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86. 51
    PubQuiz
    

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87. 52
    http://www.flickr.com/photos/sostark/26697448/
    

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88. 52
    http://www.flickr.com/photos/sostark/26697448/
    SplStack
    

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90. 53
    SplQueue
    

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91. 54
    http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/
    

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92. 54
    http://www.flickr.com/photos/blogchef/4764248456/sizes/z/in/photostream/
    Spl(Doubly)LinkedList
    

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93. 55
    http://www.flickr.com/photos/pediddle/54326823/
    

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94. 55
    http://www.flickr.com/photos/pediddle/54326823/
    SplObjectStorage
    

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96. 56
    SplPriorityQueue
    

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97. 57
    http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg
    

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98. 57
    http://farm4.static.flickr.com/3224/3072017987_ee454536da.jpg
    SplHeap
    

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99. 58
    http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg
    

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100. 58
     http://en.wikipedia.org/wiki/File:USA.NM.VeryLargeArray.02.jpg
     SplFixedArray
     

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101. 59
     ➡ Use wisely:
     ➡ Don’t use SplStack / SplQueue for
     random reads.
     ➡ Don’t use FixedArrays when you need
     speed boosts.
     

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102. 60
     EXCEPTIONS
     

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103. ➡ BadFunctionCallException
     ➡ BadMethodCallException
     ➡ DomainException
     ➡ InvalidArgumentException
     ➡ LengthException
     ➡ LogicException
     ➡ OutOfBoundsException
     ➡ OutOfRangeException
     ➡ OverflowException
     ➡ RangeException
     ➡ RuntimeException
     ➡ UnderflowException
     ➡ UnexpectedValueException
     61
     

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104. ➡ BadFunctionCallException
     ➡ BadMethodCallException
     ➡ DomainException
     ➡ InvalidArgumentException
     ➡ LengthException
     ➡ OutOfRangeException
     62
     Logic Exceptions Runtime Exceptions
     ➡ OutOfBoundsException
     ➡ OverflowException
     ➡ RangeException
     ➡ UnderflowException
     ➡ UnexpectedValueException
     

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105. 63
     1 function foo($str) {
     2 if ($str == "The Spanish Inquisition") {
     3 throw new \UnexpectedValueException("Nobody expects ".$str);
     4 }
     5 /* ... */
     6 }
     

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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
     

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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 }
     

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108. 66
     Never throw “\Exception”
     Always catch “\Exception”
     

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109. 67
     MISC
     

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110. ➡ SPL Autoloading
     ➡ SplFileInfo class
     ➡ Spl(Temp)FileObject
     ➡ ArrayObject
     ➡ SplObserver / SplSubject
     68
     

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111. 69
     Autoloader
     

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112. 70
     spl_autoload_register("spl_autoload_call");
     

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113. 70
     spl_autoload_register("spl_autoload_call");
     Throws logicException
     

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114. 71
     spl_autoload_unregister("spl_autoload_call");
     

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115. 71
     spl_autoload_unregister("spl_autoload_call");
     - Removes ALL the autoloaders!
     - Destroys the autoload stack.
     - Set your house on fire.
     

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116. 72
     ArrayObject
     

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117. 73
     ArrayObjects are not objects that acts like arrays
     ArrayObjects are objects that acts like arrays
     

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118. 74
     1 $a = array("foo", "bar");
     2 $b = $a;
     3 $b[] = "baz";
     4
     5 print_r ($a);
     6 print_r ($b);
     

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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
     )
     

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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));
     

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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
     )
     

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122. 76
     How can we make using the SPL easier?
     

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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)
     

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124. View Slide

125. ➡ Adaption of the SPL will only happen
     when developers can become familiar
     with it.
     78
     

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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
     

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127. ➡ BLOG!
     ➡ Update documentation.
     ➡ Find the quirks,
     and maybe even solve them.
     79
     

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128. http://farm1.static.flickr.com/73/163450213_18478d3aa6_d.jpg 80
     

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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
     

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