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Cosc 4750

Beginning PHP. Cosc 4750. PHP. PHP => "PHP Hypertext Preprocessor" Designed for the web Cross-platform: Runs on both UNIX and windows (with everything installed correctly) PHP is mix of PHP langauge and HTML code Runs on the Sever-side, specifically on the web server

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Cosc 4750

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  1. Beginning PHP Cosc 4750

  2. PHP • PHP => "PHP Hypertext Preprocessor" • Designed for the web • Cross-platform: Runs on both UNIX and windows (with everything installed correctly) • PHP is mix of PHP langauge and HTML code • Runs on the Sever-side, specifically on the web server • Light weight compared to PERL, since it runs inside the web-server itself. • In many ways PHP is perl, but stripped down with most of the "web" modules already installed.

  3. NOTE • I'm assuming you know several things: • HTML • SQL • PERL • I'll use PERL to explain PHP. • Also, all files are saved with the .php extension on them, instead of .html

  4. Output to browser <html> <head> <title>PHP Test</title> </head> <body> <p>Hello World</p> </body> </html> Example PHP code • file: helloworld.php <html> <head> <title>PHP Test</title> </head> <body> <?php echo "<p>Hello World</p>"; ?> </body> </html>

  5. Comments • PHP has single line comments like C++ uses the // to start a comment // This is a comment $var = 10; //bah… bah…

  6. variables • like PERL • All variables start with a $ • Unlike PERL • Variables can be typed or typeless • types: • String String data is always in double quotes • integer, double, array (numeric and hash index), object, and unknown type • Boolean (value: true or false) • Displaying variables • echo $variablename;

  7. Using Variables • Remember this is inside html code! <html><body> <? php $CarType = "Ford" $enginesize = "3.0"; $car = $cartype . " " . $enginesize; echo $car; ?> </body> </html>

  8. Constants • Don't use $, instead use a special keyword to create them • define(constantname, value); • Examples • define("FREEZING", 0); • define(INDEPENCEDAY, "4th of July"); • echo "Independence Day is ". INDEPENDENCEDAY;

  9. Variables and operators • Same as with PERL • With typed variables • numeric operators for numeric data types • string operators for string data types • such as the dot is used for concatenation with strings • can not $str = $str1 + $str2

  10. Getting data from forms • <form action="test.php" method=GET> • <!– Example input box--> • <input NAME="var1" Type="text"> • </form> • OR <form action="test.php" method=POST> <input NAME="var1" Type="text"> <!– Example input box--> </form> • The name comes into the PHP script as a variable <?php echo $var1; ?> NOTE: The name must be the same including case!

  11. Getting Data from forms • The previous example assumes that your php.ini file has • register_globals = On • This is a security risk, so by default it is off • So instead you should use • $var = $_POST['name']; //For post method • Where name is the name of name listed in the html.

  12. Getting Data from forms Example • If ($_SERVER['REQUEST_METHOD'] == 'GET') { • $var = $_GET['var']; • else • $var = $_POST['var']; • } • New version • $_REQUEST['var']; //both get and post method.

  13. Avoid errors • Use the isset function • If (isset($_REQUEST['var'])){ • $var = $_REQUEST['var']; • Else • $var = “”;

  14. Radio buttons and Check Box • <input name="choice" type="Checkbox"> • check boxes have the value of on or off • unless you use the value tag • <input name="choice" type="Checkbox" value="Computers"> • Same with Radio buttons.

  15. Filling arrays from forms • <form method=get action="test2.php"> • <input name=arr[] type=text> • <input name=arr[] type=text> • <input type=submit> • </form> • In test2.php • $arr[0] has the value of the first input and $arr[1] has the value from the second. • Note, filling Arrays won’t work if register_globals is off.

  16. HTML code input • To better "secure" your input you can use a the function HTMLSpecialChars(value); • This convert html codes into text for display. $string = HTMLSpecialChars("<B>hi</B>"); echo $string; • Will display <B>hi</b> to the web browser instead of hi.

  17. Control Structures • If statements • Again like PERL • if (boolean value) { statements } • elseif (boolean value) { statements } • else { statements } • Boolean operators are the same as in PERL, except you don't have to make any distinctions between string and numerical operators • < <= == > => !=, AND, &&, OR, ||, ! (NOT)

  18. Control Structures (2) • switch statement • NOT in perl, just like the C/C++ statement switch (variable) { case value1: statements; break; case value2: statements; break; default: statements; } • like C/C++ you can leave off the break

  19. Control Structures (3) • Loops while (boolean expression) { statements } do { statements } while (boolean expression);

  20. Control Structures (4) • for loops for (set loop counter; test loop counter; increment/decrement loop counter) { statements; }

  21. Arrays structure • foreach structure • similar to PERL foreach ($array As $variable) { statements } foreach ($array As $arrIndex => $var) { statements } • second format makes the array index value available in the loop as well.

  22. More on Arrays • Initialization (with number index values) • $arr[0] = "value1"; • $arr[1] = "value2"; • … • OR allow PHP fill in the numbers • $arr[] = "value1"; • $arr[] = "value2"; • … • OR • $arr = array ("value1", "value2", … , "valueX"); • OR (for hashing) • $arr["v1"] = "value1"; • $arr["v2"] = "vavlue2";

  23. Hashing array and return values • Many PHP functions will return an array of data, which can be used as either a hash or a “normal” array. • $date1 = localtime(); • $min = $date1["tm_min"]; • $hour = $date1["tm_hour"]; • $year = $date1["tm_year"] + 1900; • $mon = $date1["tm_mon"]+1 ;//$mon ++; • $day = $date1["tm_mday"];

  24. More on Arrays (2) • Iterating through non-sequential arrays and hash arrays. • list and each functions while ( list($indexvalue, $element) = each( $array) ) { echo "The value of element $indexvalue is $element"; }

  25. More on Arrays (3) • sorting (with index as numbers) sort($array); • sorting hash array asort($hasharray); • NOTE you can use sort on hashes, but the keys (string indices) are replaced with numbers. • reverse alphabetical order sort • rsort($array) and arsort($hasharray) • ksort($hasharray) • Sorts based on the keys, instead of the element contents.

  26. More on Arrays (4) • array_push() and array_pop() • Allows you to use an array as a stack. • implode and explode functions • $string = implode("delimiter", $array); • like join statement in PERL • $arr = explode("delimiter", $string); • like split statement in PERL

  27. functions • function functionname (parameters) { • statements; • return; • OR return value; //or variable } • Calling the function functionname(parameters); $variable = functionname(parameters);

  28. functions (2) • pass by value function f1 ($var) { // $var can be altered but won't change the // calling variable } • pass by reference function f2 (&$var) { //$var value will now change the calling variable }

  29. functions (3) • default parameter values function f3 ($var=2) { //f3 can be called with no parameters // and $var will have the value of 2 } • parameter order, since you don't have pass values to the parameters function f4($v1=2, $v2) { statements} f4(12); //$v1 =12, $v2 = 0

  30. creating global variables in functions uses the keyword global global $variable; static variables static $variable the variable will retain it's value between function calls. functions (4) • Scope of variables • Variables "declared" outside of functions are global • Variables "declared" inside functions are local variables to the function • "declared" is the first occurrence of the variable.

  31. functions (5) • final notes. • You can nest functions inside functions • the inner function will cause an error (redeclaration error) on the second time the outer function is called. • Recursion • allowed

  32. including files • include("filename"); • Execute a separate PHP script at the point in the code • include commonly used PHP functions that can be called by this script. • define variables and/or constants, etc… • Can be text or html that will be displayed.

  33. File I/O • similar to PERL file I/O • open filehandle = fopen("filename", mode); $fp = fopen("data.txt","r"); //read from file data.txt • modes • "r" read only • "w" for writing only • "a" append, create if doesn't exist. • close • fclose (filehandle);

  34. File I/O (2) • reading • $variable = fread(filehandle,bytes); $data = fread($fp, 20); // read 20 bytes from the file • Writing • fwrite(filehandle, data); fwrite($fp, "abc");

  35. File I/O (3) • $c = fgetc($fp) read file one character at a time • feof($fp) returns true if it the end of the file • $arr = file(filename) read in an entire file • Each line is an element in the $arr • copy(filename1,filename2) copy f1 to f2 • rename(f1, f2) rename f1 to f2 • unlink(filename) del filename • may not work in windows • use system or exec function (see PERL for descriptions)

  36. Directory I/O • chdir() change directory • rmdir() delete directory • mkdir() delete directory • opendir() open a directory for "reading" • readdir() read the directory • closedir() close the directory

  37. PHP database connectivity • Using mysql as the database to connect to, since it included with our Redhat installation. • First you need to connect to the database $link_id = mysql_connect("localhost", "username", "password") • like mysql command in unix mysql –u username –p password –h host

  38. PHP database connectivity (2) • Now we need to select the database to use mysql_select_db("database", $link_id); • Where $link_id is from the mysql_connect command • mysql command mysql> use database;

  39. PHP database connectivity (3) • After finishing with the database, you need to close the connection • mysql_close($link_id);

  40. PHP commands For lab 6 • <?php • // make the connection • $link_id = mysql_connect("localhost", "testacc", "csteach"); • //choose the database • mysql_select_db("webacc", $link_id); • … //now ready to retreive,modify, or delete data • mysql_close($link_id); • ?>

  41. Accessing the database • PHP uses one command to send SQL commands to the database (for mysql) • $result = mysql_query("SQL command"); • Another to retrieve results (from say a select), one row of data at a time • $arr = mysql_fetch_row($result); • //gets first row of data • $arr = mysql_fetch_row($result); • //gets next row of data • etc..

  42. With a select • $result = mysql_query("Select * from test"); • while($query_data = mysql_fetch_row($result)) { • echo "$query_data[0] $query_data[1] $queary_data[2] <BR>"; • } • //prints to the browser the contents of the table test, with three rows.

  43. With a select (2) • Or can use the field names, for better readablity. $result = mysql_query("Select * from test"); while($query_data = mysql_fetch_array($result)) { echo "$query_data["name"] $query_data["ip"] $queary_data["owner"] <BR>"; } //prints to the browser the contents of the table test, with three rows.

  44. With an Insert • $sql = "Insert into test values (‘csteach31’,’129.72.218.41’,’cosc’)"; • mysql_query($sql); • NOTE lack of return value. • NOTE: inserting "odd" characters such as ' as in I'm won't work. • There is a function to fix it called addslashes $var = addslashes("I'm"); // result "I\'m" • Removed with the stripslashes() later.

  45. Delete and update • Use the same php command $sql = "delete from test where name ='k2' "; mysql_query($sql); $sql = "update test set ip='129.72.14.123' where name = 'esig' "; mysql_query($sql);

  46. results from insert/update/delete • mysql will tell you how many how many rows were effected by insert, update or delete • There is a function to get that information from mysql • $var = mysql_affected_rows($link_id); • $var contains a the number of effected rows.

  47. example • A php script that displays the contains of a the database on a webpage <?php // make the connection $link_id = mysql_connect("localhost", "testacc", "csteach"); //choose the database mysql_select_db("webacc", $link_id); $result = mysql_query("Select * from test"); while($query_data = mysql_fetch_row($result)) { echo "$query_data["name"] $query_data["ip"] $queary_data["owner"] <BR>"; } mysql_close($link_id); ?>

  48. PHP and e-mail • Sending e-mail in PHP is very simple • On windows you need set a mailer, • command: mail( ) • It takes 4 arguments • The intended recipient • subject line • body of the e-mail • Extra headers (optional) • Example <?php mail("seker@uwyo.edu","test", "this is test message"); ?>

  49. Extra headers field • Add header like • From: • Reply-To: • Cc: • Bcc: • Others you want to create. • You need to include the \r\n between the extra headers.

  50. Example • <?php • $to = "seker@uwyo.edu"; • $subject = "Test message"; • $body = "This is a test message"; • $headers = "From:seker@uwyo.edu\r\nCc: venkat@uwyo.edu"; • mail($to,$subject,$body,$headers); • ?>

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