PHP OVERVIEW

C ONTENT Introduction of PHP History and development Basics of PHP programming

W HAT 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

H OW 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

A DVANTAGES 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

H ISTORY – 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

H ISTORY – R ELEASED VERSIONS PHP (PHP: Hypertext Preprocessor) was created by Rasmus Lerdorf in 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, 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

C URRENT 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

W HAT DO Y OU N EED 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)

B ASICS OF SYNTAX Scripting block starts with Each code line in PHP must end with a ( ; ) Comments //,# comment /* comment */ Writing of the plain text Echo “ text ” print “ text ”

V ARIABLES 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 ; ?>

V ARIABLE 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

W ORKING 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 O PERATORS

L OGICAL OPERATORS && = and || = or At least one of condition is fulfilled ! = not xor Exactly one statement is evaluated as true

C ONDITIONAL S TATEMENTS 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 cases Switch ($ var ) { case : “ x ” : echo “ good ”; break; default : echo “ wrong input ” ; }

A RRAYS 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 ";

M ULTIDIMENSIONAL A RRAYS element of array is also an array $ families = array ( " Griffin "=>array ( " Peter ", " Lois ", " Megan " ), " Soltis " =>array (“ Johny ", " Morgan " ) )

PHP L OOPING 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 L OOPING 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 <?php echo " ".$i." ".$i*$i." \n"; ?>

PHP F UNCTIONS 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 F ORMS AND U SER I NPUT Used to gain information from users by means of HTML Information is worked up by PHP Name: Age:

T HE $_GET V ARIABLE Used to collect values from a form Displays variable names and values are in the URL e=39 Can send limited amount of information (max. 100 characters) Welcome You are years old

T HE $_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 Welcome You are years old.