AIT 616 Fall 2002 PHP

AIT 616 Fall 2002 PHP  Special scripting language used to dynamically generate web documents  Open source – Free!!!  Performs common server-side tasks  Platform independent  Similar in concept to ColdFusion and ASP  Instructions embedded with HTML template  Instructions are parsed out and processed by a special program running on the Web server  Output from the instruction are incorporated back into the HTML template and sent to the client’s browser

AIT 616 Fall 2002 PHP  A relative newcomer in the server-side development arena  Gained a large following with its simple syntax and comprehensive function library  Attractive alternative to ASP for new developers  Dubbed by some to be the ‘Perl Killer’ of the server-side scripting world

AIT 616 Fall 2002 Support Servers  Windows environment  Personal Web Server  Internet Information Server (IIS)  Apache  Unix Environment  Apache (pre-configured on linux)

AIT 616 Fall 2002 Writing PHP Code  PHP code coexists with HTML code in the same file  Must enclose PHP code with special delimiters … HTML code …. <?php … php code … ?> … HTML code …

AIT 616 Fall 2002 Writing PHP Code …. <?php echo “ Hello, World ” ?> Server-side script

AIT 616 Fall 2002 Writing PHP Code …. Hello, World Client-side source code delivered to a browser

AIT 616 Fall 2002 Writing PHP Code  Comments  Double forward slash (//)  echo command  Prints out and include a \n character  Comma  Separates commands

AIT 616 Fall 2002 PHP Variables  Stores literal values  Two types  Scalar  Holds one value  String, integer, floating  Array  Holds multiple values  Case sensitive <?php $lang=‘PHP’ $num=1 ?>

AIT 616 Fall 2002 PHP Variables  Predefined  Provides a large number to any script  Are dependent upon which server is running  Version, setup, other factors  Scope  Is the context within which it is defined  For the most part, all variables have single scope

AIT 616 Fall 2002 PHP Variables <?php $a=1 function Test() { $b=$a echo $b } ?> Global Scope Local Scope

AIT 616 Fall 2002 PHP Operators  Common mathematical functions  Concatenation  Dot (.) operator  Comparison operators  Returns true or false  Boolean arithmetic <?php $x=‘ Hello,’ $y=‘World! ’ $z=$x.$y echo $z ?> Hello, World!

AIT 616 Fall 2002 PHP Decision Structures  Decision making during course of scripting processing  if statement <?php $age=26 if($age>=18) { echo ‘Register to vote!’ } ?>

AIT 616 Fall 2002 PHP Looping Structure  Iterative execution of a set of instructions  for loop  while loop <?php $num=7 $square=$num*$num while($num<$square) { if($num%2==0) { echo ‘ $num ’ } $num=$num+1 } ?>

AIT 616 Fall 2002 PHP Functions  Performs many common tasks  Large number of built-in functions  Define your own function  Functions  Apache-specific  Database specific  Network service  Mathematical  String  PDF  File system  XML parser  Session maintenance

AIT 616 Fall 2002 PHP Header() Function  Useful built-in function  Used to add a line to the HTTP header  Functionality  Type of file being sent to client  Cookies  Redirect  Host of other bits of information

AIT 616 Fall 2002 Built-in Function <?php function myFactorial($x) { $f=1 for($k=1;$k<=$x;$k++) { $f=$f*$x; } return $f } $yourNumber=4 echo ‘factorial of $yourNumber is: ‘ echo myfactorial($yourNumber) ?>

AIT 616 Fall 2002 Common Web Tasks  Responding to a form submission  PHP engine automatically stores the form data into an associative array  Using environmental variables  Stores information about a client  Function getenv()  Sending  Function mail()  Placing a cookie  Function setcookie()  Database access

AIT 616 Fall 2002 Common Web Tasks  Implementation of basic HTTP authentication to protect resources on the server  File access on the server (r/w)  Handle file uploads from a client  Session tracking

AIT 616 Fall 2002 PHP Summary  Advantages  Fairly easy to learn  Everything is built right into the language  Cross platform  Its Free!!  Active user community  Disadvantages  Language was designed to be programmer-friendly, which unfortunately makes it a little less friendly to non-programmers

AIT 616 Fall 2002 PHP Summary  Target Developer  Web developers on a budget who enjoy simple programming  PHP gives you a great deal of power with relatively simple code structure  May not be suited to very high end applications that aren’t supported by its built-in features

AIT 616 Fall 2002 PHP vs Perl  Biggest advantage of PHP over Perl is that PHP was designed for scripting for the web  PHP is less confusing and a stricter format without losing flexibility  PHP is easier to integrate into existing HTML then Perl  PHP has pretty much all the ‘good’ functionality of Perl  Perl is a very tried and true language, its been around since the late 80s, but PHP is maturing very quickly