PHP OVERVIEW

CONTENT

Introduction of PHP

History and development

Basics of PHP programming

WHAT IS PHP ?

PHP = Hypertext preprocessor

Server side scripting language

Used for development of dynamical webpages Part of typical LAMP combination Linux, Apache, MySQL and PHP

Includes a command line scripting possibility Can be used in graphical applications

HOW IT WORKS

PHP code is usually embedded into HTML

Processing the code :1) The HTML code stands as it is

2) The PHP scripts are executed to create final HTML code

3) Both parts are combined and back

4) Resulting HTML is interpreted by a browser

ADVANTAGES OF PHP

Freely available The PHP group provides complete source

code free of charge Similar syntax to C, Pearl Works with many operating systems Can be deployed on many web servers Interacts with lots of databases It is supported by many providers of

webhosting

HISTORY – INITIAL DEVELOPMENT Originally created by Rasmus Lerdorf

PHP originally stood for Personal Home Page Replaces small set of Pearl scripts Used as a tool for observing traffic on webpage

PHP 2 (PHP/FI) First publicly released version (on June 8, 1995) Combination of Lerdorf’s Form Interpreter and

original binary from PHP Was able to communicate with databases Enabled the building of dynamical web

application included Perl-like variables, form handling, and

the ability to be embedded HTML

HISTORY – RELEASED VERSIONSPHP (PHP: Hypertext Preprocessor) was created by Rasmus Lerdorf in

1994. It was initially developed for HTTP usage logging and server-side form generation in Unix.

PHP 2 (1995) transformed the language into a Server-side embedded scripting language. Added database support, file uploads, variables, arrays, recursive functions, conditionals, iteration, regular expressions, etc.

PHP 3 (1998) added support for ODBC data sources, multiple platform support, email protocols (SNMP,IMAP), and new parser written by Zeev Suraski and Andi Gutmans .

PHP 4 (2000) became an independent component of the web server for added efficiency. The parser was renamed the Zend Engine. Many security features were added.

PHP 5 (2004) adds Zend Engine II with object oriented programming, robust XML support using the libxml2 library, SOAP extension for interoperability with Web Services, SQLite has been bundled with PHP

CURRENT VERSION - PHP 5

The most recent extension (the 5.2.6) was published on May 1, 2008

Uses enhanced Zend II engine

It includes : support for object-oriented programming, the PHP Data Objects extension (simplifies

accessing databases) numerous performance enhancements

WEBSITES USING PHP

More than 20 million Internet domains are hosted on servers with PHP installed

Significant examles User-facing portion of Facebook Wikipedia (MediaWiki) Yahoo! MyYearbook

WHAT DO YOU NEED TO WORK WITH PHP?

If your server supports PHP You don’t need anything Just create some .php files in your web directory

If your server does not support PHP, you must install PHP. Download PHP Download database (MySQL) Download server (Apache)

BASICS OF SYNTAX

Scripting block starts with <?php and ends with ?>

Each code line in PHP must end with a (;)

Comments // ,# comment /* comment */ Writing of the plain textEcho “text”print “text”

VARIABLES IN PHP

Each variable starts with $ symbol

Variable name can contain only a-Z,0-9,_

It does not need to be declared before its setting.

<?php $txt = "Hello World!"; $number = 16;

?>

VARIABLE TYPES

Numerical Integer – positive as well as negative, including 0 Float – real numbers, 14 digits accuracy

Logical Boolean - True x False, not case sensitive

Alphabetical String – set of characters

WORKING WITH VARIABLES

Settype($var, “integer”) allows you to set variable according to your wish

Gettype() write the type of variable

(.) Connects 2 variables of string type

strlen() finds the length of a string

PHP OPERATORS

LOGICAL OPERATORS

&& = and || = or

At least one of condition is fulfilled ! = not xor

Exactly one statement is evaluated as true

CONDITIONAL STATEMENTS

If/ else After each statement stands (;) If more than one command should be executed,

use curly braces { }

Switch / break Used for choosing one possibility from multiple

casesSwitch ($var )

{ case : “x” : echo “good”; break;default : echo “wrong input” ;}

ARRAYS IN PHP

Numeric array Each element of array has its ID number (first

0!!) $names = array("Petr“,"Joe"); $names[0] = "Petr";

Associative Arrays Each element is assigned its value $ages = array("Peter"=>32, "Joe"=>34); $ages['Peter'] = "32";

MULTIDIMENSIONAL ARRAYS

element of array is also an array

$families = array ("Griffin"=>array

( "Peter", "Lois", "Megan" ), "Soltis" =>array

(“Johny", "Morgan" ))

PHP LOOPING

while loops repeat until final condition is reached$i =1;while ($i<=10)

{  echo $i;   $i++; }

do...while kind of reversed while function Do { code to be executed;} While(final condition);

PHP LOOPING

for Repeats the specific part of code so many times

we choose

for ($i=1; $i<=10; $i++)

Initial condition final condition running decsription

HTML INSIDE PHP

If inside quotes, the Html tags are returned as a text by PHP module

Treated as a HTML tag by

<?phpecho "<TR>

<TD>".$i."</TD><TD>".$i*$i."</TD></TR>\n";

?>

PHP FUNCTIONS

All function starts with function($parameter)

Requirements for naming functions are same as these for variables

The { mark opens the function code, while } mark closes it

It can have either defined or no parameter

More than 700 built-in functions available

PHP FORMS AND USER INPUT

Used to gain information from users by means of HTML

Information is worked up by PHP<html>

<body>

<form action="welcome.php" method="post">

Name: <input type="text" name="name" />

Age: <input type="text" name="age" />

<input type="submit" />

</form>

</body>

</html>

THE $_GET VARIABLE

Used to collect values from a form Displays variable names and values are in the

URL http://www.w3schools.com/welcome.php?

name=jo&age=39 Can send limited amount of information (max.

100 characters)<html>

<body>

Welcome <?php echo $_GET["name"]; ?> <br />

You are <?php echo $_GET["age"]; ?> years old

</body>

</html>

THE $_POST VARIABLE

Used to collect values from a form Information from a form is invisible No limits on the amount of information to be

send

<html>

<body>

Welcome <?php echo $_POST["name"]; ?><br />

You are <?php echo $_POST["age"]; ?> years old.

</body>

</html>