IT421-Web Site Development INF414-Web Based Information Systems Dr. Islam Taj-Eddin IT Dept., FCI, Assiut Univ.

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1 IT421-Web Site Development INF414-Web Based Information Systems Dr. Islam Taj-Eddin IT Dept., FCI, Assiut Univ. PHP (Files & Forms)

2 PHP Include File Insert the content of one PHP file into another PHP file before the server executes it Use the include() generates a warning, but the script will continue execution require() generates a fatal error, and the script will stop 2

3 include() example <a href="/default.php">home</a> <a href="/tutorials.php">tutorials</a> <a href="/references.php">references</a> <a href="/examples.php">examples</a> <a href="/contact.php">contact Us</a> PHP <html> <body> <div class="leftmenu"> <?php include("menu.php");?> </div> <h1>welcome to my home page.</h1> <p>i have a great menu here.</p> 3 </body> </html> PHP

PHP file I/O functions function name(s) file, file_get_contents, file_put_contents basename, file_exists, filesize, fileperms, filemtime, is_dir, is_readable, is_writable, disk_free_space

4 PHP file I/O functions function name(s) file, file_get_contents, file_put_contents basename, file_exists, filesize, fileperms, filemtime, is_dir, is_readable, is_writable, disk_free_space copy, rename, unlink, chmod, chgrp, chown, mkdir, rmdir glob, scandir category reading/writing entire files asking for information manipulating files and directories reading directories 4

5 Reading/writing files contents of foo.txt Hello how are you? I'm fine file("foo.txt") array( "Hello\n", #0 "how are\n", #1 "you?\n", #2 "\n", #3 "I'm fine\n" #4 ) file_get_contents("f oo.txt") "Hello\n how are\n you?\n \n I'm fine\n" file returns lines of a file as an array file_get_contents returns entire contents of a file as a string 5

6 Reading/writing an entire file # reverse a file $text = file_get_contents("poem.txt"); $text = strrev($text); file_put_contents("poem.txt", $text); PHP file_get_contents returns entire contents of a file as a string file_put_contents writes a string into a file, replacing any prior contents 6

7 Appending to a file # add a line to a file $new_text = "P.S. ILY, GTG TTYL!~"; file_put_contents("poem.txt", $new_text, FILE_APPEND); PHP old contents Roses are red, Violets are blue. All my base, Are belong to you. new contents Roses are red, Violets are blue. All my base, Are belong to you. P.S. ILY, GTG TTYL!~ 7

8 The file function # display lines of file as a bulleted list $lines = file("todolist.txt"); foreach ($lines as $line) {?> <li> <?= $line?> </li> <?php }?> PHP file returns the lines of a file as an array of strings each string ends with \n to strip the \n off each line, use optional second parameter: $lines = file("todolist.txt",file_ignore_new_lines); PHP 8

9 Unpacking an array: list list($var1,..., $varn) = array; PHP $values = array( mundruid", "18", f", "96");... list($username, $age, $gender, $iq) = $values; PHP the list function accepts a comma-separated list of variable names as parameters use this to quickly "unpack" an array's contents into several variables 9

10 Fixed-length files, file and list Foulan Elfoulani (002) contents of file personal.txt list($name, $phone1, $ phone2) = file("personal.txt"); PHP reads the file into an array of lines and unpacks the lines into variables Need to know a file's exact length/format 10

11 Splitting/joining strings $array = explode(delimiter, string); $string = implode(delimiter, array); $class = "CS "; $class1 = explode(" ", $s); # ("CS", 380", 01") $class2 = implode("...", $a); # "CSE " PHP PHP explode and implode convert between strings and arrays 11

12 Example explode Harry Potter, J.K. Rowling The Lord of the Rings, J.R.R. Tolkien Dune, Frank Herbert contents of input file books.txt <?php foreach (file( books.txt") as $book) { list($title, $author) = explode(,", $book);?> <p> Book title: <?= $title?>, Author: <?= $author?> </p> <?php }?> PHP 12

13 Reading directories function scandir glob description returns an array of all file names in a given directory (returns just the file names, such as "myfile.txt") returns an array of all file names that match a given pattern (returns a file path and name, such as "foo/bar/myfile.txt") 13

14 Example for glob # reverse all poems in the poetry directory $poems = glob("poetry/poem*.dat"); foreach ($poems as $poemfile) { $text = file_get_contents($poemfile); file_put_contents($poemfile, strrev($text)); print "I just reversed ". basename($poemfile); } PHP glob can match a "wildcard" path with the * character the basename function strips any leading directory from a file path glob("foo/bar/*.doc") returns all.doc files in the foo/bar subdirectory glob("food*") returns all files whose names begin with "food" glob("lecture*/slides*.ppt") examines all directories whose names begin with lecture and grabs all files whose names begin with "slides" and end with ".ppt basename("foo/bar/baz.txt") returns "baz.txt" 14

15 Example for scandir 15 <ul> <?php $folder = "taxes/old"; foreach (scandir($folder) as $filename) {?> <li> <?= $filename?> </li> <?php }?> </ul> _w2.pdf 2007_1099.doc PHP output

16 Exceptions Used to change the normal flow of the code execution if a specified error (exceptional) condition occurs. What normally happens when an exception is triggered: current code state is saved code execution will switch to a predefined (custom) exception handler function the handler may then resume the execution from the saved code state, terminate the script execution or continue the script from a different location in the code 16

17 Exception example <?php //create function with an exception function checkstr($str) { if(strcmp($str, correct )!= 0) { throw new Exception( String is not correct!"); } return true; } //trigger exception checkstr( wrong );?> PHP 17

18 Exception example <?php //create function with an exception function checkstr($str) { } //trigger exception in a "try" block try { checkstr( wrong ); //If the exception is thrown, this text will not be shown echo 'If you see this, the string is correct'; } //catch exception catch(exception $e) { echo 'Message: '.$e->getmessage(); }?> PHP 18

19 Cookies Problem: HTTP is stateless What is a cookie? tiny bits of information that a web site could store on the client's machine they are sent back to the web site each time a new page is requested by this client. 19

20 Bad Cookies? Myth: tracking, violate privacy Reality: cookies are relatively harmless can only store a small amount of information 20

21 What is a session? Sessions a combination of a server-side cookie and a client-side cookie, the client-side cookie contains only a reference to the correct data on the server. when the user visits the site: their browser sends the reference code to the server the server loads the corresponding data. 21

22 Cookies vs. Sessions Cookies can be set to a long lifespan Cookies work smoothly when you have a cluster of web servers Sessions are stored on the server, i.e. clients do not have access to the information you store about Session data does not need to be transmitted with each page; clients just need to send an ID and the data is loaded from the local file. Sessions can be any size you want because they are held on your server, 22

23 Create a cookie setcookie(name, value, expire, path, domain); PHP <?php setcookie("user", Harry Poter", time()+3600);?> <html>... PHP 23

24 Retrieve a Cookie Value <?php // Print a cookie echo $_COOKIE["user"]; // A way to view all cookies print_r($_cookie);?> PHP 24

25 Delete a Cookie <?php // set the expiration date to one hour ago setcookie("user", "", time()+3600);?> PHP 25

26 Start/end a session bool session_start ( void ) bool session_destroy ( void ) PHP $_SESSION['var'] = $val; $_SESSION['FirstName'] = "Jim"; PHP All your session data is stored in the session superglobal array, $_SESSION 26

27 Web Data Most interesting web pages revolve around data examples: Google, IMDB, Digg, Facebook, YouTube, Rotten Tomatoes can take many formats: text, HTML, XML, multimedia Many of them allow us to access their data Some even allow us to submit our own new data Most server-side web programs accept parameters that guide their execution 27

28 Reading/writing an entire file URL?name=value&name=value... query string: a set of parameters passed from a browser to a web server often passed by placing name/value pairs at the end of a URL PHP code on the server can examine and utilize the value of parameters 28

29 HTML forms form: a group of UI controls that accepts information from the user and sends the information to a web server the information is sent to the server as a query string 29

30 HTML form: <form> <form action="destination URL"> form controls </form> HTML required action attribute gives the URL of the page that will process this form's data when form has been filled out and submitted, its data will be sent to the action's URL one page may contain many forms if so desired 30

31 Form example <form action=" <div> Let's search Google: <input type="text" name="q" /> <input type="submit" value= "Submit Query" /> </div> </form> First Paragraph HTML Wrap the form's controls in a block element such as div 31

32 Form controls: <input>  <input type="text" name="q" value="colbert Report" /> <input type="submit" value="booyah!" /> HTML input element is used to create many UI controls an inline element that MUST be self-closed name attribute specifies name of query parameter to pass to server 32

33 Form controls: <input>  <input type="text" name="q" value="colbert Report" /> <input type="submit" value="booyah!" /> HTML type can be button, checkbox, file, hidden, password, radio, reset, submit, text,... value attribute specifies control's initial text 33

34 Text fields: <input> <input type="text" size="10" maxlength="8" /> NetID <br /> <input type="password" size="16" /> Password <input type="submit" value="log In" /> HTML 34 input attributes: disabled, maxlength, readonly, size, value size attribute controls onscreen width of text field maxlength limits how many characters user is able to type into field Password means characters will not appear in screen

35 Text boxes: <textarea> <textarea rows="4" cols="20"> Type your comments here. </textarea> HTML initial text is placed inside textarea tag (optional) required rows and cols attributes specify height/width in characters optional read only attribute means text cannot be modified 35

36 Check boxes: <input> <input type="checkbox" name="lettuce" /> Lettuce <input type="checkbox" name="tomato" checked="checked" /> Tomato <input type="checkbox" name="pickles" /> Pickles HTML none, 1, or many checkboxes can be checked at same time 36

37 Radio buttons: <input> <input type="radio" name="cc" value="visa" checked="checked" /> Visa <input type="radio" name="cc" value="mastercard" /> MasterCard <input type="radio" name="cc" value="amex" /> American Express HTML grouped by name attribute (only one can be checked at a time) must specify a value for each one or else it will be sent as value on 37

38 Text labels: <label> <label><input type="radio" name="cc" value="visa" checked="checked" /> Visa</label> <label><input type="radio" name="cc" value="mastercard" /> MasterCard</label> <label><input type="radio" name="cc" value="amex" /> American Express</label> HTML associates nearby text with control, so you can click text to activate control can be used with checkboxes or radio buttons label element can be targeted by CSS style rules 38

39 Drop down lists: <select>,<option> <select name="favoritecharacter"> <option>frodo</option> <option>bilbo</option> <option selected="selected">gandalf</option> <option>galandriel</option> </select> HTML option element represents each choice select optional attributes: disabled, multiple, size optional selected attribute sets which one is initially chosen 39

40 Using: <select> for lists <select name="favoritecharacter[]" size="3" multiple="multiple"> <option>frodo</option> <option>bilbo</option> <option>gandalf</option> <option>galandriel</option> <option selected="selected">aragorn</option> </select> HTML optional multiple attribute allows selecting multiple items with shift- or ctrl-click must declare parameter's name with [] if you allow multiple selections option tags can be set to be initially selected 40

41 Option groups: <optgroup> <select name="favoritecharacter"> <optgroup label="major Characters"> <option>frodo</option> <option>sam</option> <option>gandalf</option> <option>aragorn</option> </optgroup> <optgroup label="minor Characters"> <option>galandriel</option> <option>bilbo</option> </optgroup> </select> HTML What should we do if we don't like the bold italic? 41

42 Reset Buttons Name: <input type="text" name="name" /> <br /> Food: <input type="text" name="meal" value="pizza" /> <br /> <label>meat? <input type="checkbox" name="meat" /></label> <br /> <input type="reset" /> HTML specify custom text on the button by setting its value attribute 42

43 Grouping input: <fieldset>, <legend> <fieldset> <legend>credit cards:</legend> <input type="radio" name="cc" value="visa" checked="checked" /> Visa <input type="radio" name="cc" value="mastercard" /> MasterCard <input type="radio" name="cc" value="amex" /> American Express </fieldset> HTML fieldset groups related input fields, adds a border; legend supplies a caption 43

44 Common UI control errors 44 I changed the form's HTML code... but when I refresh, the page doesn't update! By default, when you refresh a page, it leaves the previous values in all form controls it does this in case you were filling out a long form and needed to refresh/return to it if you want it to clear out all UI controls' state and values, you must do a full refresh Firefox: Shift-Ctrl-R Mac: Shift-Command-R

45 Styling form controls input[type="text"] { background-color: yellow; font-weight: bold; } CSS attribute selector: matches only elements that have a particular attribute value useful for controls because many share the same element (input) 45

46 Hidden input parameters <input type="text" name="username" /> Name <br /> <input type="text" name="sid" /> SID <br /> <input type="hidden" name="school" value="uw" /> <input type="hidden" name="year" value="2048" /> HTML an invisible parameter that is still passed to the server when form is submitted useful for passing on additional state that isn't modified by the user 46

1 Form Basics CSC309

1 Form Basics CSC309 1 Form Basics Web Data 2! Most interesting web pages revolve around data! examples: Google, IMDB, Digg, Facebook, YouTube! can take many formats: text, HTML, XML, multimedia! Many of them allow us to access