1. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Chapter 2: Programming with PHP Copyright © 2012 by Larry Ullman Dr. Mogeeb Mosleh Saturday (9.00-11.00pm) SE3 Lecture Room: 405

2. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE What is PHP? PHP is an acronym for "PHP Hypertext Preprocessor" PHP is a widely-used, open source scripting language PHP scripts are executed on the server PHP costs nothing, it is free to download and use What is a PHP File? PHP files can contain text, HTML, CSS, JavaScript, and PHP code PHP code are executed on the server, and the result is returned to the browser as plain HTML PHP files have extension ".php"

3. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE What Can PHP Do? PHP can generate dynamic page content PHP can create, open, read, write, delete, and close files on the server PHP can collect form data PHP can send and receive cookies PHP can add, delete, modify data in your database PHP can restrict users to access some pages on your website PHP can encrypt data

4. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Why PHP? PHP runs on various platforms (Windows, Linux, Unix, Mac OS X, etc.) PHP is compatible with almost all servers used today (Apache, IIS, etc.) PHP supports a wide range of databases PHP is free. Download it from the official PHP resource: www.php.netwww.php.net PHP is easy to learn and runs efficiently on the server side

5. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Basic PHP Syntax A PHP script can be placed anywhere in the document. A PHP script starts with : PHP Case Sensitivity In PHP, all user-defined functions, classes, and keywords (e.g. if, else, while, echo, etc.) are NOT case-sensitive. However; in PHP, all variables are case-sensitive. Ex.

6. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Variables As with algebra, PHP variables can be used to hold values (x=5) or expressions (z=x+y). A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume). Rules for PHP variables: A variable starts with the $ sign, followed by the name of the variable A variable name must start with a letter or the underscore character A variable name cannot start with a number A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ ) Variable names are case sensitive ($y and $Y are two different variables) Variables are "containers" for storing information:

7. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Variables Scope In PHP, variables can be declared anywhere in the script. The scope of a variable is the part of the script where the variable can be referenced/used. PHP has three different variable scopes: local global static

8. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP echo and print Statements There are some differences between echo and print: echo - can output one or more strings print - can only output one string, and returns always 1 echo and print are a language construct, and can be used with or without parentheses: echo or echo().

9. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Data Types PHP Strings A string is a sequence of characters, like "Hello world!". PHP Integers An integer is a number without decimals. Rules for integers: –An integer must have at least one digit (0-9) –An integer cannot contain comma or blanks –An integer must not have a decimal point –An integer can be either positive or negative –Integers can be specified in three formats: decimal (10- based), hexadecimal (16-based - prefixed with 0x) or octal (8-based - prefixed with 0). PHP Floating Point Numbers A floating point number is a number with a decimal point or a number in exponential form. PHP Booleans Booleans can be either TRUE or FALSE. PHP Arrays An array stores multiple values in one single variable.

10. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP String Functions The PHP strlen() function: echo strlen("Hello world!"); The PHP strpos() function: echo strpos("Hello world!","world"); Complete PHP String Reference: library http://www.w3schools.com/php/php_ref_string.as p. http://www.w3schools.com/php/php_ref_string.as p Different between Echo “ “ & echo ‘ ‘;

11. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP if...else...elseif Statements In PHP we have the following conditional statements: if statement - executes some code only if a specified condition is true if...else statement - executes some code if a condition is true and another code if the condition is false if...elseif....else statement - selects one of several blocks of code to be executed switch statement - selects one of many blocks of code to be executed

12. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Loops In PHP, we have the following looping statements: while - loops through a block of code as long as the specified condition is true do...while - loops through a block of code once, and then repeats the loop as long as the specified condition is true for - loops through a block of code a specified number of times foreach - loops through a block of code for each element in an array

13. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE While Loops while (condition) { // Do something. }

14. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE For Loops for (initial expression; condition; closing expression) { // Do something. } for ($i = 1; $i <= 10; $i++) { echo $i; }

15. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Arrays In PHP, the array() function is used to create an array: In PHP, there are three types of arrays: –Indexed arrays - Arrays with numeric index –Associative arrays - Arrays with named keys –Multidimensional arrays - Arrays containing one or more arrays. –Complete PHP Array Reference http://www.w3schools.com/php/php_ ref_array.asp

16. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Creating Arrays $band[] = 'Jemaine'; $band[] = 'Bret'; $band[] = 'Murray'; $band['fan'] = 'Mel'; $band['fan'] = 'Dave'; // New value $fruit[2] = 'apple'; $fruit[2] = 'orange'; // New value $states = array ( 'IA' => 'Iowa', 'MD' => 'Maryland' ); $artists = array ('Clem Snide', 'Shins', 'Eels');

17. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Looping Through Arrays foreach ($array as $value) { // Do something with $value. } // Or: foreach ($array as $key => $value) { echo "The value at $key is $value."; }

18. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Sorting Arrays sort() - sort arrays in ascending order rsort() - sort arrays in descending order asort() - sort associative arrays in ascending order, according to the value ksort() - sort associative arrays in ascending order, according to the key arsort() - sort associative arrays in descending order, according to the value krsort() - sort associative arrays in descending order, according to the key

19. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Arrays and Strings $array = explode (separator, $string); $string = implode (glue, $array); $s1 = 'Mon-Tue-Wed-Thu-Fri'; $days_array = explode ('-', $s1); // $days_array now a five-element array, with Mon indexed at 0. $s2 = implode (', ', $days_array); // $s2 now a comma-separated list of days: Mon, Tue, Wed, Thu, Fri.

20. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Global Variables - Supergloba The PHP superglobal variables are: $GLOBALS $_SERVER $_REQUEST $_POST $_GET $_FILES $_ENV $_COOKIE $_SESSION

21. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Client/Server Environment Variables Environment variables –Provide information about execution environment Type of Web browser Type of server Details of HTTP connection –Stored as array in PHP $_ENV

22. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE An HTML Form Name: Email Address: Gender: Male Female Age: Under 30 Between 30 and 60 Over 60 Comments:

23. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PhP Form Handling Form processing –action property Where to send form data (In/Out) –method property The PHP superglobals $_GET and $_POST are used to collect form-data. Each element has unique name

24. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Choosing a Method GET The standard method for all server requests Data appended to the URL Can be bookmarked User can click Back Used for requesting information POST Data is not visible in the URL Much larger limit on the amount of data that can be submitted Can send files Users see warnings if they click Back Used for requesting action

25. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Handling a Form Use $_REQUEST['name'] Or use $_GET['name'] and $_POST['name'], depending upon the form’s method value Always load the form through a URL!

26. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Handling a Form <?php # Script 2.2 - handle_form.php // Create a shorthand for the form data: $name = $_REQUEST['name']; $email = $_REQUEST['email']; $comments = $_REQUEST['comments']; // Print the submitted information: echo " Thank you, $name, for the following comments: $comments We will reply to you at $email. \n”; ?>

27. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Form Handling GET vs. POST –Both GET and POST create an array (e.g. array( key => value, key2 => value2, key3 => value3,...)). –This array holds key/value pairs, where keys are the names of the form controls and values are the input data from the user. –Both GET and POST are treated as $_GET and $_POST. –These are superglobals, which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special. –$_GET is an array of variables passed to the current script via the URL parameters. –$_POST is an array of variables passed to the current script via the HTTP POST method

28. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Form Handling When use GET –Information sent from a form with the GET method is visible to everyone (all variable names and values are displayed in the URL). –GET also has limits on the amount of information to send (2000 characters). –GET may be used for sending non-sensitive data. When use POST –Information sent from a form with the POST method is invisible to others (all names/values are embedded within the body of the HTTP request). –has no limits on the amount of information to send. –Developers prefer POST for sending form data.

29. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Example PHP Form Handling

30. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Form Validation Proper validation of form data is important to protect your form from hackers and spammers. Check the input data weather user appropriate data or not. $_SERVER["PHP_SELF"] –The $_SERVER["PHP_SELF"] is a super global variable that returns the filename of the currently executing script. –$_SERVER["PHP_SELF"] sends the submitted form data to the page itself, instead of jumping to a different page. The htmlspecialchars() –The htmlspecialchars() function converts special characters to HTML entities. This means that it will replace HTML characters like with < and >. –This prevents attackers from exploiting the code by injecting HTML or Javascript code (Cross-site Scripting attacks) in forms. Big Note on PHP Form Security –The $_SERVER["PHP_SELF"] variable can be used by hackers! –If PHP_SELF is used in your page then a user can enter a slash (/) and then some Cross Site Scripting (XSS) commands to execute.

31. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Form Validation How To Avoid $_SERVER["PHP_SELF"] Exploits? $_SERVER["PHP_SELF"] exploits can be avoided by using the htmlspecialchars() function. "> Validate Form Data With PHP  The first thing we will do is to pass all variables through PHP's htmlspecialchars() function.  Strip unnecessary characters (extra space, tab, newline) from the user input data (with the PHP trim() function)  Remove backslashes (\) from the user input data (with the PHP stripslashes() function)  The next step is to create a function that will do all the checking for us.

32. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Validating Form Data Never trust external data! Use isset() to confirm variable has a value Use !empty() to confirm variable has a non-empty value Check the data’s type, when appropriate, for example, using is_numeric() Check the data’s value, when appropriate.

33. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Form Validation Example: ">

34. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE PHP Forms - Required Fields

35. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Common Problems Failure to load the form through a URL Incorrect reference to the PHP script (e.g., location or name) Case-sensitivity issue with PHP variables Incorrect element names in the HTML form

36. LEARN THE QUICK AND EASY WAY! VISUAL QUICKPRO GUIDE Superglobal Arrays $_GET $_POST $_REQUEST $_SERVER $_ENV $_SESSION $_COOKIE