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PHP Scripting language

PHP Scripting language. Something about PHP. PHP = PHP Hypertext Preprocessor Open-source Easy to use ( C-like and Perl-like syntax) Multiplatform Many databases support Many common built-in libraries Pre-installed in Linux distributions. Client Browser. 4. 1. PHP module. 3. Apache.

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PHP Scripting language

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  1. PHP Scripting language

  2. Something about PHP • PHP = PHP Hypertext Preprocessor • Open-source • Easy to use ( C-like and Perl-like syntax) Multiplatform • Many databases support • Many common built-in libraries • Pre-installed in Linux distributions

  3. Client Browser 4 1 PHP module 3 Apache 2 How PHP generates HTML/JS Web pages 1: Client from browser send HTTP request (with POST/GET variables) 2: Apache recognizes that a PHP script is requested and sends the request to PHP module 3: PHP interpreter executes PHP script, collects script output and sends it back 4: Apache replies to client using the PHP script output as HTML output

  4. HTML Embedding • SGML style: <? code ?> • XML style: <?php code ?> • ASP style: <% code %> • Javascript style: <script language=“php”> code</script>

  5. Integrated with HTML code • Possible within a block of statements:

  6. <html> <head> <title>My personal Hello World! PHP script</title> </head> <body> <? echo “Hello World!”; ?> </html> Hello World! (web oriented) PHP tag, allow to insert PHP code. Interpretation by PHP module will substitute the code with code output

  7. Data types • PHP Manual about data types http://tw2.php.net/manual/en/language.variables.php • Basic data types • numbers (integers and real) Decimal 1234, Octal 0777, Hex 0xff • strings Double-quoted "abc", single-quoted 'abc' • booleans true,false • Dynamic data typing • Don't have to declare types • Automatic conversion done

  8. To use or assign variable $ must be present before the name of the variable The assign operator is '=' There is no need to declare the type of the variable the current stored value produces an implicit type-casting of the variable. A variable can be used before to be assigned $A = 1; $B = “2”; $C = ($A + $B); // Integer sum $D = $A . $B; // String concatenation echo $C; // prints 3 echo $D;// prints 12 Variables (I)

  9. Function isset tests if a variable is assigned or not $A = 1; if (isset($A)) print “A isset” if (!isset($B)) print “B is NOT set”; Using $$ $help = “hiddenVar”; $$help = “hidden Value”; echo $$help; // prints hidden Value $$help = 10; $help = $$help * $$help; echo $help; // print 100 Variables (II)

  10. A string is a sequence of chars $stringTest = “this is a sequence of chars”; echo $stringTest[0]; output: t echo $stringTest; output: this is a sequence of chars A single quoted strings is displayed “as-is” $age = 37; $stringTest = 'I am $age years old'; // output: I am $age years old $stringTest = “I am $age years old”; // output: I am 37 years old Concatenation $conc = ”is “.”a “.”composed “.”string”; echo $conc; // output: is a composed string $newConc = 'Also $conc '.$conc; echo $newConc; // output: Also $conc is a composed string Strings (I)

  11. Explode function $sequence = “A,B,C,D,E,F,G”; $elements = explode (“,”,$sequence); // Now elements is an array with all substrings between “,” char echo $elemets[0]; // output: A; echo $elemets[1]; // output: B; echo $elemets[2]; // output: C; echo $elemets[3]; // output: D; echo $elemets[4]; // output: E; echo $elemets[5]; // output: F; echo $elemets[6]; // output: G; Strings (II)

  12. Groups a set of variables, every element stored into an array as an associated key (index to retrieve the element) $books = array( 0=>”php manual”,1=>”perl manual”,2=>”C manual”); $books = array( 0=>”php manual”,”perl manual”,”C manual”); $books = array (“php manual”,”perl manual”,”C manual”); echo $books[2]; output: C manual Arrays with PHP are associative $books = array( “php manual”=>1,”perl manual”=>1,”C manual”=>1); // HASH echo $books[“perl manual”]; output: 1 $books[“lisp manual”] = 1; // Add a new element Arrays (I)

  13. Working on an arrays $books = array( ”php manual”,”perl manual”,”C manual”); Common loop for ($i=0; $i < count($books); $i++) print ($i+1).”-st book of my library: $books[$i]”; each $books = array( “php manual”=>1,”perl manual”=>2,”C manual”=>3); while ($item = each( $books )) // Retrieve items one by one print $item[“value”].”-st book of my library: ”.$item[“key”]; // each retrieve an array of two elements with key and value of current element each and list while ( list($value,$key) = each( $books )) print “$value-st book of my library: $key”; // list collect the two element retrieved by each and store them in two different // variables Arrays (II)

  14. Multidimensional arrays $books = array( array(“title”=>“php manual”,”editor”=>”X”,”author”=>”A”), array(“title”=>“perl manual”,”editor”=>”Y”,”author”=>”B”), array(“title=>“C manual”,”editor”=>”Z”,author=>”C”)); Common loop for ($i=0; $i < count($books); $i++ ) print “$i-st book, title: ”.$books[$i][“title”].” author: “.$books[$i][“author”]. “ editor: “.$books[$i][“editor”]; // Add .”\n” for text new page or “.<BR>” for HTML new page; Use list and each for ($i=0; $i < count($books); $i++) { print “$i-st book is: “; while ( list($key,$value) = each( $books[$i] )) print “$key: $value ”; print “<BR>”; // or “\n” } Arrays (III)

  15. Arithmetic Operators

  16. Logical Operators

  17. Comparison Operators

  18. C-like syntax • For loops • While • switchcasebreak • ++ / -- • elseif

  19. <!--#! /usr/local/bin/php --> <html> <body> <h2>Radio buttons example</h2> <form><tableborder=0><tr><th>Button</th><th>Text</th></tr><?php for ($j=1; $j<6; $j++) { $rbname = "rbn"; $rbvalue = "rbv_".$j; $rbtext = "Text_".$j; $radio = "input type=\"radio\" name=\"$rbname\" value=\"$rbvalue\" " ; if ($j == 3) $radio .= " checked=\"checked\" "; echo "<tr><td align =\"center\"><$radio></td> <td>$rbtext</td></tr>"; };?></table> </form></body></html> LOOPING EXAMPLE

  20. Arrays Construct arrays using the array() function: $numbers = array(5,4,3,2,1) $words = array(“Web”,”Database”,”Interactive”,”Apps”) Numbered arrays: accessed by numeric indexDefault: Index of 1st element is 0. Echo $words[0]; // Web Echo $words[3]; // Apps $words() = “GUI”; // adds a 5th element to the above $words(5) = “Usability”; // adds 6th element

  21. Associative Arrays Also called string-indexed arrays Uses key to access values stored in the array: $catch_it[‘cat’] = “mouse”; $catch_it[‘dog’] = “cat”; echo catch_it[‘dog’]; // prints “cat”

  22. … <h2>Radio buttons array example</h2> <form><tableborder=0><tr><th>Button</th><th>Text</th></tr><?php $pizza_type = array("Ham","Sausage","Pepperoni","Anchovies","Cheese");for ($j=1; $j<6; $j++) { $rbname = "rbn"; $rbvalue = "rbv_".$j; $rbtext = $pizza_type[$j -1]; $radio = "input type=\"radio\" name=\"$rbname\" value=\"$rbvalue\" " ; if ($j == 3) $radio .= " checked=\"checked\" "; echo "<tr><td align =\"center\"><$radio></td> <td>$rbtext</td></tr>"; };?></table></form></body></html> Array Example

  23. Form Handling (1) • Three methods • Short: $varfoo (the variable name defined in the <FORM>) • Medium: $_POST[‘varfoo’], (recommended for versions of PHP +4.1) • Long: $HTTP_POST_VARS[‘varfoo’] • Need register_globals ON for short method to work. If register_globals = on, the EGPCS (Environment, GET, POST, Cookie, Server) variables are regarded as global variables. • Tip: For checkbox variables your variable name should end with [ ] • Checkbox results are automatically put into an array • Example: <input type=checkbox name=foo[] value=Y>

  24. Form Handling (2) “action.php” • Traditional: • Since PHP 4.2: • Better: less danger for incorrect programs “form.php”

  25. PHP Variables from a Form <html><body><?phpif ( $name ) { print( "Hello, $name !");} else { // form entry print( "<form action=\"$PHP_SELF\" method=post>\n"); print( "Your name: <input type=text size=10 name=name ><br>\n"); print("<input type=submit value=Submit>\n" ); print("</form>\n");}?></body></html>

  26. Passing variables via URL You can test by setting variables through a URL: http://localhost/php/urlvariables.php?var1=This+is+a+String&var2=3.1415159265 (urlvariables.php) <!--#! /usr/local/bin/php --><html><body><?php echo "$var1 <br>"; ?><?php echo "$var2 <br>";?></body></html>

  27. Dates Date and Time is carried in Unix timestamp:Number of seconds since 1 Jan 1970 GMT To create a timestamp, use mktime(): int mktime(int hour, int minute, int second, int month, int day, int year [, int is_dst] Ex: $aDate = mktime(9, 30,0,6,18,1998) 9:30 A.M. on June 18, 1998 String to timestamp: $var = strtotime(“25 December 2002”)

  28. Formatting a Date Date() function: string date(string format, [int timestamp]) $var = mktime(8, 15, 25, 8, 24, 1964); echo date(‘d/m/Y’,$var); // “24/08/1964” echo date(‘m/d/y’,$var); // “08/24/64” echo date(‘m/d/y); // “03/12/03” (today) Many powerful formatting arguments: see the PHP on-line manual.

  29. Other Functions Absolute Value: echo abs(-1); // prints 1 Ceiling and Floor: integer above or below float echo ceil(27.3); // prints 28 echo floor(27.3); // prints 27 Rounding: Up or down value to given precision echo round(10.4); // prints 10 echo round(10.5); // prints 11 echo round(2.40964,3); // prints 2.410

  30. Random Number Generation Random number generation: needs seeding // generate a seed$seed = (float) srand(microtime() * 100000000; // seed the random number generatorsrand($seed); // generate random numbersecho rand(); // between 0 and getmaxrand() echo rand(1,6); // random numbers between // 1 and 6, inclusive

  31. User-Defined Functions <?php function doublevalue($var) {$returnVal = $var * 2;return($returnVal);}$var = 5;$temp = doublevalue($var);echo "$temp";?>

  32. function function_name([parameters-list]opt) {……implementation code……} parameters-list is a sequence of variables separated by “,” it’s not allowed to overload the name of an existing function; Function names aren’t case-sensitive; To each parameter can be assigned a default value; arguments can be passed by value or by reference It’s possible using a variable number of parameters Syntax to define a function

  33. Passing Arguments • Passing By Value: (outputs 5) function square($p) { return $p*$p; } $a=5; echo square($a); • Passing By Reference: (outputs 25) function square($p) { return $p*$p; } $a=5; echo square(&$a);

  34. Variable Scope • Local and Global are the only options • Variables defined within functions have scope local to that function. • To access a global variable from within a function use the GLOBAL keyword: function test() { global $a; echo $a; } $a = “the quick brown fox”; test(); • Alternatively use $GLOBALS array: function test() { echo $GLOBALS[“a”]; } $a = “the quick brown fox”; test();

  35. Include Files You can put several functions into a file and save it: <?php function doublevalue($var) {$returnVal = $var * 2;return($returnVal);}function bold($string){echo "<b>" . $string . "</b>\n";}?>Save this file as stdfunctions.inc

  36. Using Include Files <html><body><?include "stdfunctions.inc";echo "this is not bold <br>\n" ;bold("this is bold");echo "<br>again, this is not bold <br> \n";bold(doublevalue(3.14));?></body></html>

  37. #cat /usr/local/myDatabaseDirectory/library.txt php manual X A 330 perl manual Y B 540 C manual Z C 480 (fields separated by tabs: 'php manual<tab>X<tab>A', new line at the end of each entry) <? // script to show all book in my library $books = file(“/usr/local/myDatabaseDirectory/library.txt”); // retrieve library “database” for ($i=0; $i<count($books), $i++ ) $books_array[$i] = explode( “\t”, $books[$i]); // Extract elements from line ... for ($i=0; $i<count($books_array), $i++ ) print “$i-st book, title: ”.$books_array[$i][“title”].” author: “.$books_array[$i][“author”]. “ editor: “.$books_array[$i][“editor”].”<BR>”; File Access

  38. Sessions • A session is the time a client spends on a site. • A session id is stored (as a cookie) on the client OR passed along via the URLs (using php only). The id is a key to session information stored on the server for each client. • Php sessions will work even if cookies have been disabled by the person using the browser • Session information is stored on the server.

  39. PHP Sessions • session_start(); called at each script using the session variables • $total = …. • $cart["pencils"] = $qty; • $cart[$productname] = $productqty; • session_register("total"); • session_register("cart"); • any other script, can use $cart and $total. • $result = session_is_registered("total"); • session_unregister("total"); • session_destroy();

  40. Object Oriented PHP • Encapsulation • Polymorphism • Inheritance • Multiple Inheritance: actually unsupported

  41. $val4 = (($month+1)*3)/5; $val5 = $year/4; $val6 = $year/100; $val7 = $year/400; $val8 = $day+($month*2)+$val4+$val3+$val5-$val6+$val7+2; $val9 = $val8/7; $val0 = $val8-($val9*7); return $val0; } } // Main $instance = new dayOfWeek($_GET[“day”],$_GET[“week”],$_GET[“ month”]); print “You born on “.$instance->calculate().”\n”; ?> Encapsulation <? class dayOfWeek { var $day,$month,$year; function dayOfWeek($day,$month,$year) { $this->day = $day; $this->month = $month; $this->year = $year; } function calculate(){ if ($this->month==1){ $monthTmp=13; $yearTmp = $this->year - 1; } if ($this->month == 2){ $monthTmp = 14; $yearTmp = $this->year - 1; }

  42. Allow the creation of a hierarchy of classes Inheritance Class reuseMe { function reuseMe(){...} function doTask1(){...} function doTask2(){...} function doTask3(){...} } Class extends reuseMe { function example(){ ... // local initializations // call super constructor reuseMe::reuseMe(); } function doTask4(){...} function doTask5(){...} function doTask6(){...} }

  43. Polymorphism A member function can override superclass implementation. Allow each subclass to reimplement a common interfaces. class reuseMe { function reuseMe(){...} function doTask1(){...} function doTask2(){...} function doTask3(){...} } Class extends reuseMe { function example(){ ... // local initializations // call super constructor reuseMe::reuseMe(); } function doTask4(){...} function doTask5(){...} function doTask6(){...} function doTask3(){...} }

  44. Class example class Cart { var $items; // Items in our shopping cart // Add $num articles of $artnr to the cart function add_item ($artnr, $num) { $this->items[$artnr] += $num; } // Take $num articles of $artnr out of the cart function remove_item ($artnr, $num) { if ($this->items[$artnr] > $num) { $this->items[$artnr] -= $num; return true; } else { return false; } } }

  45. Inheritance example Class ParentObject {    var $value;   function ParentObject() {        $this->value = 42;   } } class MemberObject extends ParentObject {    var $string;    function MemberObject() {       $this->string = "This is a test string."; $this->ParentObject();   } } class ObjTest {    var $ObjPointer;   function ObjTest() {        $tmp = new MemberObject; $this->ObjPointer = $tmp;   } } $object = new ObjTest; echo "String Contents: " . $object->ObjPointer->string . "\n"; echo "Value  Contents: " . $object->ObjPointer->value . "\n";

  46. class extends reuseMe1,reuseMe2 {...} Multiple Inheritance not actually supported by PHP class reuseMe1 { function reuseMe1(){...} function doTask1(){...} function doTask2(){...} function doTask3(){...} } class reuseMe2 { function reuseMe2(){...} function doTask3(){...} function doTask4(){...} function doTask5(){...} }

  47. Overview of MySQL • Relational database management system (RDBMS) • Free • Website @ http://www.mysql.com/

  48. MySQL Basics • Common SQL Statements • INSERT • SELECT • UPDATE • DELETE • Simple Join • Entity-Relationship (ER) Modeling • An Easy Way to Manage Your MySQL DBs

  49. MySQL Basics (cont.) • A relational database manager (MySQL) manages databases which holds tables which has records (rows) with attributes (columns) • Each record must have a unique ID, also known as a Primary Key. When used as an identifier in another table it’s called a Foreign Key. Used for joins. • Each attribute has to have a data type. (e.g. int, text, varchar) • A database language (SQL) is used to create and delete databases and manage data

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