Can't Miss Features of PHP 5.3 and 5.4

Can’t Miss Features of
PHP 5.3 and 5.4

Jeff Carouth BCSPHP Sept. 15, 2011

1

Hi! I am Jeff

Senior Developer at Texas A&M
Author of several magazine articles (php|architect)
Infrequent (lazy) blogger at carouth.com
Lover of progress, innovation, and improvement.
Developing with PHP since ~2003

2

About you?

New to PHP?
Using PHP 5.3?
Used PHP yesterday? this afternoon?

3

What’s all the hubbub?

__DIR__
SPL improvements
Closures / anonymous functions / lambda functions
Namespaces

5

__DIR__
“under under durrr”

6

__DIR__ usefulness

Cleanup autoloading code.
That’s about it.

include_once dirname(__FILE__) . "/../myfile.php";

include_once __DIR__ . "/../myfile.php";

7

SPL Improvements

SPLFixedArray

SPLDoublyLinkedList

SPLStack and SPLQueue

SPLHeap, SPLMinHeap, SPLMaxHeap

SPLPriorityQueue

8

We have shiny new data
structures. Use them instead of
arrays where appropriate!

9

The PHP folk are trying to
confuse you…

11

...because not all
anonymous functions are
closures...

12

…which aren’t the same as
lambda expressions or
functors.

13

You say semantics? No.
There is a difference.

(But I’ll step off my soapbox for now. Feel free to ping
me later.)

14

function() {
print 'Hello';
};

$myhello = function() {
print "Hello!";
};

$myhello();

$myhelloname = function($name) {
print "Hello, " . $name . "!";
};

$myhelloname('BCSPHP');

15

function get_closure($name) {
$person = new stdclass();
$person->name = $name;

return function() use($person) {
print "Hello, " . $person->name . "!";
};
}

$myhelloclosure = get_closure('Gernonimo');
$myhelloClosure();
// Output: "Hello, Geronimo!"

$myhelloclosure is said to “close over” the
$person variable which is within its deﬁned scope.

16

Using Lambdas

array_walk, array_map, array_reduce
usort, uasort
array_filter
preg_replace_callback

17

$fabrics= array(
array('color' => 'blue'),
array('color' => 'red'),
array('color' => 'green'),
array('color' => 'maroon')
);

usort($fabrics, function($a, $b) {
return strcmp($a['color'], $b['color']);
});

18

// filter based on dynamic criteria
define('MINUTE', 60);
define('HOUR', 3600);
define('DAY', 86400);
define('WEEK', 604800);
$accounts = array(
array('id' => 1, 'lastActivity' => time()-2*WEEK),
array('id' => 2, 'lastActivity' => time()-3*DAY),
array('id' => 3, 'lastActivity' => time()-45*MINUTE),
array('id' => 4, 'lastActivity' => time()-2*HOUR-5*MINUTE),
array('id' => 5, 'lastActivity' => time()-5),
array('id' => 6, 'lastActivity' => time()-3*MINUTE-20),
array('id' => 7, 'lastActivity' => time()-2*WEEK-3*DAY),
array('id' => 8, 'lastActivity' => time()-HOUR-33*MINUTE),
array('id' => 9, 'lastActivity' => time()-5*MINUTE),
);

19

$results = array();
$oneweek = time()-WEEK;
foreach ($accounts as $account) {
if ($account['lastActivity'] > $oneweek) {
$results[] = $account;
}
}

$results = array_filter(
$accounts,
function($account) {
return $account['lastActivity'] > time()-WEEK;
}
);

20

$getfilterfunc = function($lower, $upper = 0) {
$lowerTime = time() - $lower;
$upperTime = time() - $upper;

return function($account)
use($lowerTime, $upperTime) {
return $account['lastActivity'] >= $lowerTime
&& $account['lastActivity'] <= $upperTime;
}
}

$pastWeekResults = array_filter(
$accounts,
$getfilterfunc(WEEK));
$previousWeekResults = array_filter(
$accounts,
$getFilterFunc(2*WEEK, WEEK));

21

MOAR PRACTICAL

Caching.
Typically you have a load() and save()
method.
Perhaps even a load(), start(), and end()
method.

23

class SimpleCache {
private $_data = array();

public function load($key) {
if (!array_key_exists($key, $this->_data)) {
return false;
}
return $this->_data[$key];
}

public function save($key, $data) {
$this->_data[$key] = $data;
}
}

$cache = new SimpleCache();
if (($data = $cache->load(‘alltags’)) === false) {
$service = new ExpensiveLookupClass();
$data = $service->findAllTags();
$cache->save(‘alltags’, $data);
}

24

class SimpleCacheWithClosures {
protected $_data = array();

public function load($key, $callback) {
if (!array_key_exists($key, $this->_data)) {
$this->_data[$key] = $callback();
}
return $this->_data[$key];
}
}

$cache = new SimpleCacheWithClosures();

$service = new ExpensiveLookupClass();
$data = $cache->load('alltags', function() use($service) {
return $service->findAllTags();
});

25

Functors
Because the rest just wasn’t enough…

26

Functors, in simple terms,
are objects that you can call
as if they are functions.

27

class Send {
private function _broadcast() {
return 'Message sent.';
}

public function __invoke() {
return $this->_broadcast();
}
}

$send = new Send();
debug_log($send());

28

Namespaces

All the cool languages have them.
or perhaps PHP just wants to be JAVA
with all its package glory
after all, we do have PHARs

29

Nope. Namespaces solve a
real need.

30

The “” Separator

31

Namespace Benefits

Organization. Both file and code.
Reduce conflicts with other libraries.
Shorten class names.
Readability.

32

define("LIBRARYDIR", __DIR__);

class Tamu_Cas_Adapter {
function auth() { }
}

function tamu_cas_create_client() {
return new Tamu_Http_Client();
}

namespace TamuCas;
use TamuHttpClient as HttpClient;

const LIBRARYDIR = __DIR__;

class Adapter {
function auth() { }
}

function create_client() {
return new HttpClient();
}
33

Namespace organization

In /path/to/Tamu.php:
namespace Tamu;

In /path/to/Tamu/Dmc.php
namespace TamuDmc;

In /path/to/Tamu/Auth/Adapter/Cas.php
namespace TamuAuthAdapter;
class Cas { }

34

Conﬂict Resolution

namespace My;
function str_split($string, $split_len = 2) {
return "Nope. I don't like to split strings.";
}

$splitstr = str_split('The quick brown fox');
// $splitstr = "Nope. I don't like to split strings."

$splitstr = str_split('The quick brown fox');
// $splitstr = array('T', 'h', 'e', ..., 'o', 'x');

35

Class name shortening

class Zend_Application_Resource_Cachemanager
extends Zend_Application_Resource_ResourceAbstract
{
//...
}

namespace ZendApplicationResource;
class Cachemanager extends ResourceAbstract
{
//...
}

36

Readability by Namespace

require_once "Zend/Http/Client.php";
$client = new Zend_Http_Client();

use ZendHttp;
$client = new Client();

use ZendHttpClient as HttpClient;
$httpClient = new HttpClient();

37

PHP 5.4

alpha3 was used for demos
beta going to be packaged on Sep 14
(source:php-internals)

39

New Features

Closures support $this keyword
Short Array Syntax
Array Dereferencing
Traits
(Debug webserver)

40

Closures and $this
class HelloWorldPrinter
{
public function __construct($name) {
$this->_name = $name;
}

public function getPrinter() {
return function() {
return "Hello, " . $this->_name . "!";
};
}
}

$instance = new HelloWorldPrinter('BCSPHP');
$printer = $instance->getPrinter();

echo $printer();
41

Prior to PHP 5.4
Fatal error: Using $this when not in object context in /
Users/jcarouth/Documents/code-bcsphp-092011/
php54closurethis.php on line 14

PHP 5.4.0alpha3 (built Aug 5, 2011)
Hello, BCSPHP!

42

Short Array Syntax
Saving you a few keystrokes
and compute cycles when switching from JavaScript

43

Really, who doesn’t love
JavaScript array syntax?

44

//empty array
$arr = [];

//simple array
$arr = [1, 2, 3];

//"dictionary" array
$arr = ['name' => 'jeff', 'language' => 'php'];

//multi-dimensional
$arr = [['orange', 'blue'], ['black', 'gold']];

45

Array Dereferencing
46

$array = array(1, 2, 3);
$dereference = *$array;

Sorry, no pointers.
All the upset C++ wizards, go have some pizza.

47

class UserDataSource
{
public function getDataForJeff()
{
return [
'id' => 1,
'name' => 'Jeff Carouth',
'isAdmin' => true,
];
}
}

$jeff = $store->getDataForJeff();
if ($jeff['isAdmin'] === true) {
//give him access to all the things
}
PHP <= 5.3
if ($store->getDataForJeff()['isAdmin']) {
//shorter...but be mindful
}
48
PHP >= 5.4

Pitfalls

Dereferencing a non-existent key produces a
NOTICE.
If the function does not return an array,
unexpected behavior.

49

Deﬁnition

Traits is a mechanism for code reuse in single
inheritance languages such as PHP. A Trait is
intended to reduce some limitations of single
inheritance by enabling a developer to reuse
sets of methods freely in several independent
classes living in different class hierarchies. The
semantics of the combination of Traits and
classes is defined in a way, which reduces
complexity and avoids the typical problems
associated with multiple inheritance and Mixins.

51

A bit much to
take in
The important bit is traits
allow developers like you to
increase code reuse and get
around limitations of single-
inheritance.

52

Show me the code!

trait Named {
function name() {
//function body
}
}

53

class SearchController {
public function findBook(Book $b) { }

private function log($message) {
error_log($message);
}
}

class AdminController {
public function grant(User $u, Privilege $p) { }

}
}

54

trait Logging {
}
}

class SearchController {
use Logging;
}

class AdminController {
use Logging;
}

55

namespace TamuTimesModels;
class Story {
public function setDataStore($store) {
$this->_ds = $store;
}

public function getDataStore() {
return $this->_ds;
}
}

class User {
}

return $this->_ds;
}
}

56

namespace TamuDmcApp;
trait DataStore {
}

return $this->_ds;
}
}

namespace TamuTimesModels;
use TamuDmcAppDataStore;
class Story {
use DataStore;
}

class User {
use DataStore;
}

57

namespace BCSPHP;
trait MessageBroadcast {
public function sendMessage() { }

abstract private function _formatMessage();
}

class MeetingNotification {
use MessageBroadcast;

private function _formatMessage() {
return "Notice: BCSPHP Meeting " . $this->_date;
}
}

58

Traits are “just compiler
assisted copy and paste.”
- Stefan Marr, PHP Internals Mailing List, Nov 2010

59

Built-in Development Server

60

DEMO

php -S 0.0.0.0:8080 -t /path/to/docroot

61

Caveat

Routing must be handled with a separate
router.php script.

if (file_exists(__DIR__ . '/' . $_SERVER['REQUEST_URI'])) {
return false; // serve the requested resource as-is.
} else {
include_once 'index.php';
}

if (php_sapi_name() == 'cli-server') {
/* route static assets and return false */
}

62

What you can do now:

(more like what you should do)
Test PHP 5.4 — http://qa.php.net
Run make test
TEST YOUR APPS against PHP 5.4-alpha/beta/RC

63

That’s all folks!

QUESTIONS?

@jcarouth

jcarouth@gmail.com

jeffcarouth.info

64

Have feedback?

http://joind.in/3716

65

Resources

Enygma’s PHP 5.3 example code
http://bit.ly/q9Eu36
Elazar’s benchmarks of SPL features in PHP 5.3
http://bit.ly/nKsbvQ
PHP documentation on the built-in web server
http://bit.ly/rc26l0

66

Can't Miss Features of PHP 5.3 and 5.4

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