Php Crash Course - Macq Electronique 2010

PHP Crash Course Macq Electronique, Brussels 2010 Michelangelo van Dam

Targeted audience experience with development languages knowledge about programming routines types and functions this is not “development for newbies” !

Michelangelo van Dam • Independent Consultant • Zend Certiﬁed Engineer (ZCE) - PHP 4 & PHP 5 - Zend Framework • Co-Founder of PHPBenelux • Shepherd of “elephpant” herdes

T AIL O RM A D E S O L U T I O N S Macq électronique, manufacturer and developer, proposes you a whole series of electronic and computing-processing solutions for industry, building and road traffic. Macq électronique has set itself two objectives which are essential for our company : developing with competence and innovation earning the confidence of our customers Macq électronique presents many references carried out the last few years which attest to its human and technical abilities to meet with the greatest efficiency the needs of its customers. For more information, please check out our website http://www.macqel.eu

What is PHP ? • most popular language for dynamic web sites • open-source (part of popularity) •- pre-processed programming language no need to compile • simple to learn (low entry level) • easy to shoot yourself in your foot ! (no kidding)

PHP is a “Ball of nails” “When I say that PHP is a ball of nails, basically, PHP is just this piece of shit that you just put together—put all the parts together—and you throw it against the wall and it fucking sticks.” Terry Chay

History of PHP •- 1995: Rasmus Lerdorf created PHP for maintaining his own resume on the web - called it “Personal Home Page” - improved it with a Form interpreter (PHP-FI) • 1997: Zeev Zuraski and Andi Gutmans - rewrote ﬁrst parser for PHP v3 - renamed it “PHP: Hypertext Preprocessor” • 1998: Zeev Zuraski and Andi Gutmans - redesigned the parser for PHP 4 (Zend Engine) - founded Zend Technologies, Inc.

Why PHP ?

Seriously, who uses PHP ? “PHP is currently the most popular server-side web programming language. It runs 33,53%˙ of the websites on the Internet.” Source: wheel.troxo.com ˙ data from 2007 !!! PHP powers adult websites !!!

Starting with PHP •- Minimum Requirements: php hypertext preprocessor (www.php.net) - a text editor (notepad, textpad, vi, pico, emacs, …) • Preferred requirements: - LAMP: Linux, Apache, MySQL, PHP - WAMP: Windows, Apache, MySQL, PHP - WIMP: Windows, IIS, MS SQL, PHP - SPAM: Solaris, PHP, Apache, MySQL - Mac OS X

Where to start ? http://php.net

Easy installation http://www.zend.com/community/zend-server-ce

My ﬁrst PHP code Put the following code in ﬁle “helloWorld.php”: <?php echo 'Hello World'; ?> To execute this code you can just use user@server: $ /usr/local/zend/bin/php ./helloWorld.php And it will output Hello Worlduser@server: $

What about websites ?

Some dry theory first • Basic syntax • Exceptions • Types • References Explained • Variables • Predefined Variables • Constants • Predefined Exceptions • Expressions • Predefined Interfaces • Operators • Context options and • Control Structures parameters • Functions • Classes and Objects • Namespaces Same as on http://php.net/manual/en/langref.php

Basic syntax • Escaping from HTML • Instruction separation • Comments

Escape from HTML Simple escaping: This is going to be ignored. <?php echo 'While this is going to be parsed.'; ?> This will also be ignored. Advanced escaping: <?php if ($expression) { ?> This is true. <?php } else { ?> This is false. <?php } ?>

Instruction separation <?php echo 'This is a test'; ?> <?php echo 'This is a test' ?> <?php echo 'We omitted the last closing tag';

Comments <?php // single line comment if ($condition) { // another single line c++ style comment /* This is a multi-line comment that spans over multiple lines */ echo 'This is a test'; echo 'This is another test'; # with a single line shell style comment } A common mistake is to nest multi-line comments ! /* This multi-line comment /* has a nested multi-line comment spanning two lines */ */ The last */ will never be reached !!!

Types • Booleans • Objects • Integers • Resources • Floating point • NULL numbers • Pseudo-types • Strings • Type Juggling • Arrays

Scalar types • boolean (have a TRUE or FALSE state) •- integer (decimal, octal or hexadecimal) positive numbers (1,204, …) - negative numbers (-9, -128, …) - hexadecimal numbers (0x1A, 0xFF, …) - octal numbers (0123, 0777, …) • ﬂoat (a.k.a. ﬂoats, doubles, real numbers) - 1.234, 1.2e3, 7E-10, … • string

Single quoted strings <?php echo 'this is a simple string'; // this is a simple string echo 'this is a ' . 'combined string'; // this is a combined string echo 'this is a multi- // this is a multi-line string line string'; echo 'I'm an escaped character string'; // I'm an escaped character string $var = '[var]'; echo 'this $var is not processed'; // this $var is not processed

Double quoted strings <?php echo "this is a simple string"; // this is a simple string echo "this is a " . "combined string"; // this is a combined string echo "this is a multi- // this is a multi-line string line string"; echo "I'm an escaped character string"; // I'm an escaped character string $var = '[var]'; echo "this $var is processed"; // this [var] is processed

Compound Types • array • object

Arrays •- ordered map collection of keys and values ❖ keys: can only be an integer or a string ❖ values: can be of any type

Example arrays $myArray = array (1, 2, 3, 4); // array[0] = 1; array[1] = 2; // array[2] = 3; $myArray = array (1, 'Hello World'); // array[0] = 1; // array[1] = 'Hello World'; $myArray = array (1 => 'a', 2 => 'b'); // array[1] = 'a'; array[2] = 'b'; $myArray = array ('a' => 1, 'b' => 2); // array['a'] = 1; array['b'] = 2; $myArray = array ( 'a' => array (1, 2, true), // array['a'] = array[0] = 1; // array[1] = 2; // array[2] = true; 'b' => array ( // array['b'] = 'a' = 1, // array['a'] = 1; 'b' = false, // array['b'] = false; 'c', // array[0] = 'c'; ), );

Objects <?php class foo { function do_foo() { echo "Doing foo."; } } $bar = new foo; $bar->do_foo(); ?> Outputs Doing foo More about objects in the advanced PHP session…

Special Types • resource • NULL

Resource •- Special type holds a reference to an external source ❖ a database, a ﬁle, a stream, … - can be used to verify a resource type

NULL • represents a variable with no value •- a variable is considered null when assigned the NULL constant - it has no value assigned yet - has been emptied by unset()

Pseudo Types • mixed: used for any type • number: used for integers and ﬂoats •- callback: a function (name) is used as parameter - a closure or anonymous function (as of PHP 5.3) - cannot be a language construct

Type Juggling • no explicit type deﬁnitions of variables •- type of variable can change remember the shoot in the foot part ! • enforced type casting to validate types Confused yet ?

Type Juggling example <?php $foo = "0"; // $foo is string (ASCII 48) $foo += 2; // $foo is now an integer (2) $foo = $foo + 1.3; // $foo is now a float (3.3) $foo = 5 + "10 Little Piggies"; // $foo is integer (15) $foo = 5 + "20 Small Pigs"; // $foo is integer (25) ?>

Variables • Basics • Predeﬁned variables • Variable scope • Variable variables

Basics <?php $var = 'Bob'; $Var = 'Joe'; echo "$var, $Var"; // outputs "Bob, Joe" $4site = 'not yet'; // invalid; starts with a number $_4site = 'not yet'; // valid; starts with an underscore $täyte = 'mansikka'; // valid; 'ä' is (Extended) ASCII 228.

Basics in PHP 6

Predeﬁned Variables • Superglobals: are built-in variables (always available in all scopes) • $GLOBALS: References all variables available in global scope • $_SERVER: Server and execution environment information • $_GET: HTTP GET variables • $_POST: HTTP POST variables • $_FILES: HTTP File Upload variables • $_REQUEST: HTTP Request variables • $_SESSION: Session variables • $_ENV: Environment variables • $_COOKIE: HTTP Cookies • $php_errormsg: The previous error message • $HTTP_RAW_POST_DATA: Raw POST data • $http_response_header: HTTP response headers • $argc: The number of arguments passed to script • $argv: Array of arguments passed to script

Variable Scope context in which a variable is deﬁned <?php $a = 1; include ‘file.inc.php’; // $a is known inside the included script global scope <?php $a = 1; $b = 2; function foo() { global $a, $b; echo $b = $a + $b; } foo(); // outputs 3 echo $b; // outputs 3 ($b is known outside it’s scope)

Variable Variables <?php $a = ‘php’; // value ‘php’ stored in $a $$a = ‘rules’; // value ‘rules’ stored in $$a (or $php) echo “$a ${$a}”; // outputs ‘php rules’ echo “$a $php”; // outputs ‘php rules’

Constants • an identiﬁer (name) for a simple value • that value cannot change • is case-sensitive by default • are always uppercase (by convention) •- 2 types basic - magic

Basic Constants <?php define(‘CONSTANT’, ‘value’); define(‘KEY_ELEMENT’, 1); define(‘SYNTAX_CHECK’, true); echo CONSTANT // outputs ‘value’ echo Constant // outputs ‘Constant’ and issues a notice As of PHP 5.3 const CONSTANT = ‘value’; echo CONSTANT; // ouputs ‘value’

Magic Constants • __LINE__: current line number of the file • __FILE__: full path and filename of the file • __DIR__: directory of the file • __FUNCTION__: function name (cs) • __CLASS__: class name (cs) • __METHOD__: class method name (cs) • __NAMESPACE__: current namespace (cs)

Expressions $a = 5; function foo() { return ‘bar’; } 0 < $a ? true : false; $a = $b = 2; // both $a and $b have a value of 2 $c = ++$b; // $c has value 3 and $b has value 3 $d = $c++; // $d has value 3 and $c has value 4

Operators • Operator Precedence • Arithmetic Operators • Assignment Operators • Bitwise Operators • Comparison Operators • Error Control Operators • Execution Operators • Incrementing/Decrementing Operators • Logical Operators • String Operators • Array Operators • Type Operators

Control structures • if • declare • else • return • elseif/else if • require • while • include • do-while • require_once • for • include_once • foreach • goto • break • continue • switch

Functions <?php function a($n){ b($n); return ($n * $n); } function b(&$n){ $n++; } echo a(5); //Outputs 36

Next step: advanced PHP Classes and Objects Abstraction Security PHP Hidden Gems

Recommended Reading CYAN YELLOW MAGENTA BLACK BOOKS FOR PROFESSIONALS BY PROFESSIONALS ® THE EXPERT’S VOICE® IN OPEN SOURCE Companion eBook Available PHP for Absolute Beginners PHP for Absolute Beginners Dear Reader, PHP for Absolute Beginners will take you from zero to full-speed with PHP programming in an easy-to-understand, practical manner. Rather than building PHP applications with no real-world use, this book teaches you PHP by walking you through the development of a blogging web site. You’ll start by creating a simple web-ready blog, then you'll learn how to add password-protected controls, support for multiple pages, the ability to upload and resize images, a user comment system, and finally, how to integrate with sites like Twitter. Along the way, you'll also learn a few advanced tricks including creating friendly URLs with .htaccess, using regular expressions, object-oriented programming, and more. I wrote this book to help you make the leap to PHP developer in hopes that you can put your valuable skills to work for your company, your clients, or on your own personal blog. The concepts in this book will leave you ready to take on the challenges of the new online world, all while having fun! PHP for Absolute Beginners for Absolute Beginners Jason Lengstorf THE APRESS ROADMAP Apress PHP Objects, Patterns, Pro PHP: PHP for and Practice Patterns, Frameworks, Absolute Beginners Testing, and More Beginning PHP Practical Web 2.0 and MySQL Applications with PHP Jason Lengstorf Everything you need to know to Beginning Ajax and PHP Companion eBook get started with PHP See last page for details on $10 eBook version Lengstorf SOURCE CODE ONLINE www.apress.com Jason Lengstorf US $34.99 Shelve in: PHP User level: Beginner this print for content only—size & color not accurate trim = 7.5" x 9.25" spine = 0.75" 408 page count

Credits Ball of nails - Count Rushmore http://flickr.com/photos/countrushmore/2437899191 Life is too short for Java - Terry Chay http://flickr.com/photos/tychay/1388234558 Ruby Fails - IBSpoof (stickers by @spooons) http://www.flickr.com/photos/ibspoof/2879088241 Monkey Face - Mr Pins http://flickr.com/photos/7359188@N02/1358576877 Unicode Identifiers - Andrei Zmievski / Andrew Mager http://andrewmager.com/geeksessions-13-php-scalability-and-performance/ Confused - Kristian D. http://flickr.com/photos/kristiand/3223044657

Questions ? Slides on SlideShare http://www.slideshare.net/DragonBe Give feedback ! http://joind.in/1256

Php Crash Course - Macq Electronique 2010

by Michelangelo van Dam on Jan 27, 2010

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