Community Heckling On twitter #tek09 (or #phptek) and #spldg DG’s for drinking game (you’ll see why later) IRC is open, I can see backlog – constructive criticism is good Comment on http://joind.in/talk/view/186 No comments on hair, clothes, or my fat belly – constructive criticism is welcome ;)
I have a ProblemRecursively iterate through directoriesFind all .jpg filesCheck last modified datesMoved the ones older than two years to new location
How should I do this? Some nasty recursive use of scandir() to get my lists Or PHP’s dir() function and looping array_map() with a convoluted callbackI think I’m going to need a lot of code….
SPL to the Rescue! RecursiveDirectoryIterator RecursiveIteratorIterator FilterIterator SplFileInfo What fun tools we have!
What is SPL? tandard HP ibrary A library of standard interfaces, classes, and functions designed to solve common programming problems and allow engine overloading.
That’s nice… in English please.What is SPL?1. Engine overloading hooks via interfaces ArrayAccess, Countable, SeekableIterator2. Classes that utilize the interfaces do cool things ArrayObject, RecursiveIterator, DirectoryIterator3. Standard Class Implementations Exceptions, SplObserver and SplStorage4. Functions to help with autoloading and objects spl_autoload_register(), spl_classes(), iterator_apply()
But… it’s an extension right? SPL is an extension SPL is a core extension SPL cannot be built shared SPL should not be turned off SPL is present in PHP since 5.0 (almost 5 years ago) As of 5.3, SPL cannot be turned off without altering sourceIf you don’t have SPL, whoever built your PHP is an idiot(or an evil genius – it’s HARD).
Autoload Magic spl_autoload() – default autoload implementation spl_autoload_register() – add an autoload to the stack spl_autoload_unregister() – remove an autoloader spl_autoload_functions() – what’s on the stack spl_autoload_extensions() – ext for spl_autoload() spl_autoload_call() – load something through the stack
Isn’t __autoload good enough? Combining different libraries with different naming conventions Dealing with different types of files (templates, classes) in different locations Changing autoload in use during runtime
Object Helper Functions class_implements() class_parents() spl_object_hash()Why are these not in core?I DON’T KNOW - GO ASK YOUR DAD!
Exception Classes RuntimeExceptionOutofBoundsExce OverflowExceptio UnderflowExcepti UnexpectedValueE RangeException ption n on xception
So what does SPL offer? A standard set of Exceptions that all inherit from PHP’s Exception base class A standard way to set up exceptions by what kind they are Do I recommend it? Depends on how exceptions are used in your application.
Foreach is your bestest friend! Foreach an object today!
The iterator drinking game! Every time someone says the word iterator tonight, take a drink Start a conversation with me, and you’ll be gone in about five minutes It’s the SPL drinking game (tonight at cocktail hour)
Iterators What the heck is an iterator? A design pattern that is a generic solution to the problem of iterating over data in a consistent manner. Access the elements of an aggregate object sequentially without exposing its underlying representation. Why do I care? Ever need to go over a list of items returned from a database (well, duh) Or need to go over a list of items returned from a webservice? Ever used foreach?
Foreach it baby! Foreach is your friend iterators give your code consistent usage and you can add more functionality What else can you do with iterators? Extend Iterators to do what you need Chain Iterators: iteratoriteratoriteratoriterator(that’s 5 shots)….
So how is it different?Array $ar= array(); Iterator $it = new Iterator; can be rewound Might be rewindable reset($ar) $it->rewind() is valid unless the key is NULL should know if there is a value !is_null(key($ar)) $it->valid() Has a current value Might have a current value or current($ar) key Has keys $it->key() key($ar) $it->current() can move forward Can move forward next($ar) $it->next()
Innie or an Outie? OuterIterator (interface) Extends Iterator Puts a wrapper around an iterator inside Has one additional method – getInnerIterator() that should be implemented
Loopety Loop RecursiveIterator (interface) Has two additional methods to implement getChildren should return the sub-iterator for the current element – and it must return an object that implements recursiveIterator hasChildren
Jumping ahead? SeekableIterator (interface) Additional method – seek(string $position) Lets you jump to a specific spot to start iterating
Now on to classes Classes implement interfaces plus provide additional functionality Interfaces need you to fill in all the the required methods You can implement multiple interfaces You can’t extend multiple classesChoose Wisely
FilterIterator Abstract Class Has one method that must be implemented – accept – which should return true or false File filtering example at the beginning used this Highly useful for many types of iteration FilterIterator OuterIterator Iterator Traversable
IteratorIterator Regular Class Iterates an iterator – No I am not kidding IteratorIterator OuterIterator Iterator Traversable
ArrayIterator Regular Class Iterates an array – OR the public properties of an object! (neat trick – dirty trick) ArrayAccess and ArrayIterator SeekableIterator Iterator Traversable Countable too!
RecursiveIteratorIterator Regular Class Like IteratorIterator only recursive to boot – still not kidding - but I don’t say it as cool as Marcus RecursiveIteratorIterator OuterIterator Iterator Traversable
ParentIterator Regular Class Filter out stuff without children ParentIterator OuterIterator Iterator Traversable
LimitIterator Regular Class Like mysql’s limit – pick your range and offset and foreach away! LimitIterator OuterIterator Iterator Traversable
CachingIterator Regular Class Manages another iterator by checking whether it has more elements each time using a hasNext() method CachingIterator OuterIterator Iterator Traversable
RecursiveCachingIterator Regular Class Just like caching iterator only – believe it or not – recursive! RecursiveCachingIterator CachingIterator OuterIterator Iterator Traversable
DirectoryIterator Regular Class Makes going through directories a snap isDot, isFile – I love you SplFileInfo DirectoryIterator Iterator Traversable (extends)
RecursiveDirectoryIterator Regular Class Like, do it again… and again… and again… and… DirectoryIterator RecursiveIterator Iterator Traversable (extends)
Iterator Helper Functions iterator_apply() – like array_walk for your iterator implementing objects iterator_count() – count the items in your iterator (not quite the same as implementing countable::count) iterator_to_array() – copy all the stuff from your iterator into a regular PHP arrayEven Supermandoesn’t work alone
ArrayObject A class, NOT an interface It’s like arrayaccess on RedBull The manual LIES – for a full list of everything you can do with arrayobject, see http://www.php.net/~helly/php/ext/spl/ Highlights exchangeArray getArrayCopy (get your internally stored array) Sorting methods ksort et al
Countable Interface you can implement with any class (not iterator specific, but used a lot for it) Implement the count method and you can use the count() PHP function on any object
SplObjectStorage This does not do what you think it does Use objects as array keys, uniquely, with no collision issues (you might get them from spl_object_hash) Remember you need the object to get the data back out, unless you’re simply iterating over the contents Regular class, no need to extend and fill in methods http://www.colder.ch/news/01-08- 2009/34/splobjectstorage-for-a-fa.html
SPLFixedArray A fixed length, int key only array Why? It’s FAST (very fast) because it stores data differently “under the hood” in C Regular class, don’t need to extend and fill in any methods 5.3+
SplObserver and SplSubject Abstract classes for anything using an observer pattern http://www.a-scripts.com/object-oriented- php/2009/02/21/the-observer-pattern/ - great common sense tutorial If you do event/observers in your code, extending these two makes good sense
SplFileInfo fancy class for a file all the file system functions in compact object form getMTime == filemtime openFile == fopen
New and Shiny SplDoublyLinkedList SplStack SplQueue
More Data Structures SplHeap SplPriorityQueue SplMaxHeap SplMinHeap
The Documentation Problem http://elizabethmariesmith.com/2009/02/setting-up- phd-on-windows/ - you can write docbook on any platform! Efnet - #php.doc channel http://doc.php.net firstname.lastname@example.org – mailing list See me and start helping today!
Resources http://php.net/spl - spl docs http://php.net/~helly/php/ext/spl - Doxygen docs http://blueparabola.com/blog/spl-deserves-some- reiteration - some stuff about new data structures email@example.com