PHP

1. PHP Dynamic Web programming

2. PHP - history • PHP is a language for creating interactive web sites.  • It was originally called "Personal Home Page Tools" when it was created in 1994 by RasmusLerdorf to keep track of who was looking at his online resume. • Mid-1997: Students AndiGutmans and ZeevSuraskiredesigned the PHP language engine and wrote some of the most popular PHP modules.  • At that time PHP already had its own site, php.net, run by the computer science community, and was powering thousands of Web sites. • The script was just beginning to be recognized by developers who preferred the multi-platform script over its more limited Microsoft ASP counterpart that interfaces only with Windows NT.  • Today PHP Web developers applaud the script's simplicity, flexibility, and ability to generate HTML pages quickly. Over 5,100,000 (1/2001) sites around the world use PHP. 

3. What is PHP? • PHP is a server-side scripting language, like ASP • PHP scripts are executed on the server • PHP supports many databases (MySQL, Informix, • Oracle etc.) • PHP is open source and free to download • PHP files many contain text, HTML tags and scripts • PHP files are returned to the browser as plain HTML • PHP files have extension of “.php”, “.php3” or • “.phtml”

4. Why PHP? • PHP runs on different platforms (windows, Linux etc) • PHP is compatible with almost all servers used • today (Apache, IIS etc) • PHP is FREE to download from official PHP resource: • http://www.php.net • PHP is easy to learn and runs efficiently on the • server side

5. PHP vs ASP • Php - Open source  asp - not • Php - Very fast !!!  Asp - ?? • Php - Superior Memory Management • Asp - windows memory management  • Php - No Hidden Costs with PHP • asp - (Need encryption - buy ASPEncrypt. Need email management - buy ServerObject'sQMail. Need file uploading - buy Software Artisans SA-FileUp. 

6. PHP vs ASP • The following databases are currently supported: Adabas D Ingres Oracle (OCI7 and OCI8) dBase InterBaseOvrimosEmpress FrontBasePostgreSQLFilePro (read-only) mSQL Solid Hyperwave Direct MS-SQL Sybase IBM DB2 MySQLVelocis

7. PHP vs ASP • Php-> HTTP GET and POST variables are automatically created as global variables (security??) asp->i have to "Request." my HTTP GET and POST variables??  • Php-> if your phpscript is not working , you can blame no one but yourself asp-> You can blame Micro$oft, iis , asp and so on...  • Php-> you don't have time for a coffie break because your computer never crashes asp-> you have a lot of coffie breaks ... 

8. What you need for PHP? • Install an Apache Server (web server) on a windows or • Linux machine • Install PHP (server side scripting technology) on a • windows or Linux machine • Install MySQL (database server) on a windows or Linux • machine And lots of Configuration work!!! • Alternatively, Just download WAMP Server and install • It will not only installs Apache, MySQL and PHP on windows • machine but will also configure these software. • Provides you an easy to access interface to run and host • PHP files.

9. PHP is C++ Style • PHP is very similar to C++. • As a consequence if you know java (also a c++ clone), C++ or • indeed almost any other computer science language you pretty • much already know PHP. • However more than anything PHP is based on Perl. • PHP is an Embedded Script • You could view PHP as an embedded language. • However it is very much still a Server Side Language – this is not the same sort of thing as Javascript

10. Creating a PHP program • You can use any text editor. (Notepad,Dreamweaver) • Different Web server setups work in different ways. (we will • use XAMPPServer that bundles Apache, MySQL, PHP) • Create a new file in Dreamweaver and save it with .php • extension. • Use <?phpTo open your code and ?> to close it. • Anything not in those tags is rendered as HTML. • Type your code and load it up in a web browser. • Any webpage that use even a single line of php and all other • contents are in HTML must be saved with .php extension. • Otherwise phpcode will not run.

11. PHP Tag Styles • XML Style: • <?php • print “this is XML style”; • ?> • Short Style: • <? • print “this is ASP style”; • ?> • To use Short style, the PHP you are using must have “short tags” enabled in its configfile… this is almost always the case.

12. Hello, PHP ! • simple output : ("CGI Style")  • <? echo "<html><head></head><body>Hello world! • <br></body></html>"; ?>  • simple output 2 : (embeded style)  • <html> <head></head> <body> <?print "Hello world!" ?><br> </body>  • More ways of Escaping from HTML : PHP3 style:  • <?phpecho "Hello world!";  ?> 

13. Hello, PHP ! • the "<script>" tag:  • <script language="php">  echo "Hello world!"; </script>  • ASP style ():  • <% echo "hello world"; %> 

14. /*PHP Comments*/ • <? //comment # comment /* multi line comment (c++ style) */ ?> 

15. PHP is for Lazy People • Basic data types • Scalar • numbers (integers and float. Holds 4 bytes of space) • strings (Double-quoted "abc“ and single-quoted 'abc' ) • booleans(true, false ) • Compound • Arrays • Objects • Dynamic typing • Don't have to declare types • Automatic conversion done

16. PHP $Variables • Every variable must have a $ sign at the beginning of the variable. • <? • $x = false; // boolean • $x = true; • $x = 10; // decimal • $x = 1.45; // Floating point • $x = ’Hello World’; // Hello World • $x = "mmm\"oo'oo"; // mmm"oo'oo • $y = &$x; // Reference • $x[1] = 10; // array of decimals • $x["name"] = “jimbo"; // associative array • $x[2]["lala"] = "xx"; // a two dimensional array • ?>

17. Variable substitution • Variable substitution provides a convenient way to embed data held in a variable directly into string literals. • PHP examines, or parses , double-quoted strings and replaces variable names with the variable's value. • The following example shows how: • <? • $number = 45; • $vehicle = "bus"; • $message = "This $vehicle holds $number people"; • // prints "This bus holds 45 people" • print $message; • ?>

18. PHP $Variables • Type Juggling :  • <? $x = "100"; $x++; // $x is now 101 ?>  • Variable variables: (@#%^!!)  • <? $moo = "xxx"; $a = "moo"; $$a = "boo"; echo "variable \$a is '$a' and \$moo is '$moo'.<br>"; // will output: variable $a is 'moo' and $moo is 'boo'; ?> 

19. Constants • Constants associate a name with a scalar value. • For example, the Boolean values true and false are constants associated with the values 1 and 0, respectively. • It's also common to declare constants in a script. • Consider this example constant declaration: • <? • define("PI", 3.14159); • // This outputs 3.14159 • print PI; • ?>

20. Type conversion • Conversion between types can be pure (forced) or dirty (automatic)… • Forced casting (pure): • <? • $bool = true ; • print (int)$bool ; • ?> • Automatic Type Juggling (dirty): • <? $x = "100"; • $x++; // $x is now 101 • ?> • Check Point: • If $x = "12" and $y = "13" What will be the output for $x . $y and $x + $y?

21. Variable Scope • The 3 basic types of scope in PHP is: • Global variables declared in a script are visible throughout that script, but not inside functions • Declared as: global $x; • Variables used inside functions are local (limited) to the function • By default a variable inside a function is local. • You can also define a local variable as: local $x; • Variables used inside functions that are declared as globalrefer to the global variable of the same name

22. Operators • + Addition - Subtraction * Multiplication / Division % Modulus & And | Or ^ Xor. add string (like in perl) << Shift left >> Shift right 

23. Assignment Operators • <? $x = "Hello "; $x.= "wrold!"; $x = 10; $x++; $x *= 5; $x = array(1,3,2,4,10); $x = array(      "a" => "4",      "i" => "1",      "e" => "3",      "later"  => "l8r" ); ?> 

24. Comparison Operators • $a == $b Equal - True if $a is equal to $b.  • $a === $b Identical - True if $a is equal to $b, and they are of the same type.  • $a != $b Not equal - True if $a is not equal to $b.  • $a !== $b Not identical - True if $a is not equal to $b, or they are not of the same type.  • $a < $b Less than - True if $a is strictly less than $b.  • $a > $b Greater than - True if $a is strictly greater than $b.  • $a <= $b Less than or equal to - True if $a is less than or equal to $b.  • $a >= $b Greater than or equal to - True if $a is greater than or equal to $b. 

25. Comparison Operators • the ? operator - like the C operator:  • <?echo ($x==0) ? "X value is zero" : "X value is not zero"; ?> 

26. Logical Operators • $a and $b True if both $a and $b are true.  • $a or $b True if either $a or $b is true.  • $a xor $b True if either $a or $b is true, but not both.  • ! $a True if $a is not true.  • $a && $b True if both $a and $b are true.  • $a || $b True if either $a or $b is true. 

27. Simple String functions • chr - Return a specific character • ord - Return ASCII value of character • strlen - Get string length • strpos - Find position of first occurrence of a string • strrev - Reverse a string • strtolower - Make a string lowercase • strtoupper - Make a string uppercase • str_replace - Replace all occurrences of the search string with the replacement string

28. Control Structures • if:  • <? if ($a > $b) {     print "a is bigger than b";     $b = $a; } ?>  • else: • <? if ($a > $b) {     print "a is bigger than b"; } else {     print "a is NOT bigger than b"; } ?> 

29. Control Structures • elseif:  • <? if ($a > $b) {     print "a is bigger than b"; } elseif ($a == $b) {     print "a is equal to b"; } else {     print "a is smaller than b"; } ?> 

30. While loops • While:  • <? $i = 1; while ($i <= 10) {     print $i++;  /* the printed value would be                     $i before the increment                     (post-increment) */ } ?>  • do .. while:  • <? $i = 0; do {    print $i++; } while ($i< 10); ?> 

31. For loops • <? /* example 1 */ for ($i = 1; $i <= 10; $i++) {     print $i; } /* example 2 */ for ($i = 1;;$i++) {     if ($i > 10) {         break;     }     print $i; } 

32. foreachloops • <? /* values */ $a = array (1, 2, 3, 17); foreach ($a as $v) {    print "Current value of \$v: $v.<br>"; } /* values and keys */ $a = array (1, 2, 3, 17); foreach($a as $k => $v) {     print "\$a[$k] is $v<br>"; } ?> 

33. switch • <? switch ($i) {     case 0:         print "i equals 0";         break;     case 1:         print "i equals 1";         break;     case 2:         print "i equals 2";         break;     default:         print "i is not equal to 0, 1 or 2"; } ?> 

34. includes • <? include("/libs/mylib1.inc"); include_once("/libs/mylib2.inc"); ?> 

35. Predefined variables • <? $x = $SERVER_NAME; #The name of the server host  $x = $REQUEST_METHOD; #'GET', 'HEAD', 'POST' or 'PUT' $x = $PHP_SELF; #The filename of the currently executing script $x = $HTTP_COOKIE_VARS["Varname"]; $x = $HTTP_GET_VARS["Varname"]; $x = $HTTP_POST_VARS["Varname"]; # variables that were posted using post, get or cookie. $x = $REMOTE_ADDR;  # The IP address from which the user is viewing the current page.  ?> 

36. functions • <? function la(){      return "lalala\n<br>"; }  echo la(); // will output lalala?> 

37. functions • Variable scope:  • <?$x = "XXX"; functionput_in_x($myparam){      $x = $myparam; }  put_in_x("YYY"); echo $x; // will output XXX ?> 

38. functions • using global variables in a function.  • <?$x = "XXX"; function put_in_x($myparam){      global $x;     $x = $myparam; }  put_in_x("YYY"); echo $x; // will output YYY ?> 

39. variables functions • (partial list) empty - Determine whether a variable is set isset - same as !empty($a) gettype - Get the type of a variable get_defined_vars- Returns an array of all defined variables is_array- Finds whether a variable is an array is_bool- Finds out whether a variable is a booleanis_float - Finds whether a variable is a float is_int - Find whether a variable is an integer is_null - Finds whether a variable is NULL is_numeric- Finds whether a variable is a number or a numeric string is_object- Finds whether a variable is an object is_string - Finds whether a variable is a string unset - Unset a given variable  • functions for debugging : print_r- Prints human-readable information about a variable var_dump - Dumps information about a variable 

40. string functions • (partial list) chop - Strip whitespace from the end of a string chr - Return a specific character crypt - DES-encrypt a string hebrev - Convert logical Hebrew text to visual text htmlspecialchars - Convert special characters to HTML entities md5 - Calculate the md5 hash of a string nl2br - Inserts HTML line breaks before all newlines in a string ord - Return ASCII value of character sprintf- Return a formatted string strip_tags- Strip HTML and PHP tags from a string addslashes - Quote string with slashes stripslashes - Un-quote string quoted with addslashes() 

41. string functions • strlen- Get string length strpos - Find position of first occurrence of a string strrev- Reverse a string strtolower - Make a string lowercase strtoupper - Make a string uppercase str_replace - Replace all occurrences of the search string with the replacement string join - Join array elements with a string split - split string into array by regular expression  • <? $date = "04/30/1973";  // Delimiters may be slash, dot, or hyphen list ($month, $day, $year) = split ('[/.-]', $date); echo "Month: $month; Day: $day; Year: $year<br>\n"; ?> 

42. array functions • (partial list) count - Count elements in a variable array_pop - Pop the element off the end of array array_push - Push one or more elements onto the end of array array_reverse - Return an array with elements in reverse order array_shift - Shift an element off the beginning of array array_unshift - Prepend one or more elements to the beginning of array array_sum - Calculate the sum of values in an array. array_unique- Removes duplicate values from an array array_values- Return all the values of an array in_array - Return TRUE if a value exists in an array array_search- Searches the array for a given value and returns the corresponding key if successful sizeof - Get the number of elements in variable sort - Sort an array uksort - Sort an array by keys using a user-defined comparison function usort - Sort an array by values using a user-defined comparison function 

43. array functions • <? function cmp ($a, $b) {        if ($a == $b) return 0;     return ($a < $b) ? -1 : 1; } $a = array (3, 2, 5, 6, 1); usort ($a, "cmp"); ?>  • array_flip- Flip all the values of an array  • <? $trans = array ("a" => 1, "b" => 1, "c" => 2); $trans = array_flip ($trans); // now $trans is : array(1 => "b", 2 => "c"); ?> 

44. Object oriented • <?php// base class with member properties and methods class Vegetable { var $edible; var $color;     function Vegetable( $edible, $color="green" ) {         $this->edible = $edible;         $this->color = $color;     }     function is_edible() {         return $this->edible;     }     function what_color() {         return $this->color;     }  • } // end of class Vegetable • // extends the base class class Spinach extends Vegetable {     var $cooked = false;     function Spinach() {     $this->Vegetable ( true, "green" );     }     function cook_it() {         $this->cooked = true;     }     function is_cooked() {         return $this->cooked;     }    } // end of class Spinach $veggie = new Vegetable(true,"blue"); $leafy = new Spinach(); ?> 

45. HTML Forms • the form.php (or form.html): • <form action="receive.php" method="post"> • Name: <input type="text" name="username"><br> • <input type="submit"> • </form> • recv.php- the file that will receive the data:  • <? • $username = $_POST[“username”]; • if($username) • print "your name is $username <br>"; • else • { • ?> • <a href="form.php">please fill the form!</a> • <? • } • ?>

46. "All in one" Form • same in one file (PHP style):  • <? • $username = $_POST[“username”]; • if($username) • { • echo "your name is $username !!! <br>"; • } • else • { • ?> • <form action="<?= $PHP_SELF ?>" method="post"> • Name: <input type="text" name="username"><br> • <input type="submit"> • </form> • <? • } • ?>

47. Trimming Strings • trim() strips whitespace from the start and end of a string and returns the result. • It also gets rid of new lines, tabs, carriage returns • and the like. • ltrim() and chop() do similar things – but only from one end of the string.

48. Changing Case • Most people who use your sites will be Muppets. (although • your sites will probably only be viewed by members of staff so • draw your own conclusions). • Whatever you tell them to do, they won’t enter data in the • format you want and this will matter. Login names are • classic examples of this. • Imagine someone types “aStOnVillA” into a field… • Strtoupper() Turns string to uppercase ASTON VILLA • Strtolower()Turns string to lowercase aston villa • Ucfirst()Capitalisesfirst character Aston villa • Ucwords()Capitalises every word Aston Villa

49. Adding Slashes • To do this escaping normally you just add a \ (backslash). • This can be very painful to do manually. • AddSlashes() a function to do it for you. • StripSlashes() reverses the process. • So if a user typed in: You said to me that “you don’t give gaurantees” • $userInput = AddSlashes($userInput) • You said to me that /“you don/’t give gaurantees/”.

50. Exploding Strings • explode() returns an array of strings created by breaking the subject string at each occurrence of the separator string. • Syntax: explode(sep, subject); • $email = falak.nawaz@seecs.edu.pk”; • $arr = explode(“@”, $email); $arr[0] = “falak.nawaz” $arr[1] = “seecs.edu.pk” • $domains = explode(“.”, $arr[1]); $domain[0] = “seecs” $domain[1] = “edu” $domain[2] = “pk” • Implode() reverses the process.