PHP POWERPOINT SLIDES

Server-side programming & PHP
 server-side includes
 Netscape LiveWire
 Active Server Pages (ASP)
 Java Servlets
 PHP
− variables, control statements, file access
− form handling
− file uploading, email redirection
Internet & Web Programming

PHP
2
 PHP is similar to JavaScript, only server-side
PHP code is embedded in HTML using tags
when a page request arrives, the server recognizes PHP content via the file
extension (.php , .php3, or .phtml)
the server executes the PHP code, substitutes output into the HTML
the resulting page is then downloaded to the client
user never sees the PHP code, only the output in the page
developed in 1995 by Rasmus Lerdorf (member of the Apache Group)
 originally designed as a tool for tracking visitors at Lerdorf's Web site
 within 2 years, widely used in conjunction with the Apache server
 developed into full-featured, scripting language for server-side programming
 free, open-source
 server plug-ins exist for various servers

PHP execution
3
PHP code can be embedded within a <?php...?> tag
output is displayed using print

<html>
<head>
<title>Server-side Hello</title>
</head>
<body>
<table border=1 align="center">
<tr><td>
<?php print("Hello and welcome to <i>my</i> page!"); ?>
</table>
</body>
</html>

<html>
<head>
<title>Server-side Hello</title>
</head>
<body>
<tr><td>
Hello and welcome to <i>my</i> page!
</table>
</body>
</html>
the server executes the
print statement, substitutes
output, downloads
resulting page

PHP variables
4
similar to JavaScript, PHP variables are not declared, dynamically typed
scalar data types: Boolean, integer, double, string
compound data types: array, object
special types: resource, NULL
all variable names begin with $
<html>
<head>
<title>Server-side Fortune</title>
<?php
$list = array("Live long and prosper",
"Save for tomorrow",
"You will meet someone");
$fortune = $list[rand(0, count($list)-1)];
?>
</head>
<body>
<tr><td>
<?php print($fortune); ?>
</table>
</body>
</html>
variables are flexible
 any unassigned variable has
value NULL
 can test if NULL using IsSet
e.g., IsSet($name)
 can set mode so that
unbound access is reported,
or automatically coerced to
default values

PHP: handling form data
5
 <html> 
 <head> <title>Server-side Greeting</title> </head>
 <body>
 <?php
 $yourName = $_POST['yourName'];
 print("Hello and welcome to my page <i>$yourName</i>.<br />n");
 print("If you like it, " .
 "<a href='mailto:davereed@creighton.edu'>email me</a>!n");
 ?>
 </body>
 </html>
can write server-side programs in PHP as an alternative to CGI
 no need for CGIinput class, can use either GET or POST
 form data is automatically accessible via variable with form element name
 similar to Perl, '.' is used for string concatenation
<html> 
<head> <title>PHP Form Handling</title> </head>
<body>
<form action="http://empirical.cs.creighton.edu/~davereed/helloNice.php"
method="post">
Enter your name: <input type="text" name="yourName"/>
<br /><br />
<input type="submit" value="click for greeting" />
</form>
</body>
</html>

PHP: email database example
6
<html>
<head> <title>PHP Email DB</title>
<?php
$emailDB = array("Jim Carlson", "carlsn@creighton.edu",
"Davendar Malik", "malik@creighton.edu",
"Prem Nair", "psnair@creighton.edu",
"Dave Reed", "davereed@creighton.edu",
"Mark Wierman", "wierman@creighton.edu");
?>
</head>
<body>
<?php
$person = $_POST['person'];
print("Search results for: " . $person . "<br /><br />n");
$found = false;
for ($i = 0; $i < count($emailDB); $i+=2) {
if ($person == "" ||
strpos("?".strtolower($emailDB[$i]), strtolower($person))) {
$entry1 = $emailDB[$i];
$entry2 = $emailDB[$i+1];
print("$entry1: <a href='mailto:$entry2'>$entry2</a><br />n");
$found = true;
}
}
if (!$found) {
print("No matching names were found. Please try again.<br />n");
}
?>
</body>
</html>
since PHP source is not
seen by user, can
embed protected data
safely
string functions
include:
• strlen
• strcmp
• strpos
• substr
• strtolower
• strtoupper
• trim

PHP: file example
7
<html>
<head>
<title>PHP Email DB</title>
<?php
$emailDB = file("email.txt");
?>
</head>
<body>
<?php
$person = $_POST['person'];
print("Search results for: " . $person . "<br /><br />n");
$found = false;
for ($i = 0; $i < count($emailDB); $i+=2) {
if ($person == "" ||
strpos("?".strtolower($emailDB[$i]), strtolower($person))) {
$entry1 = $emailDB[$i];
$entry2 = $emailDB[$i+1];
print("$entry1: <a href='mailto:$entry2'>$entry2</a><br />n");
$found = true;
}
}
if (!$found) {
print("No matching names were found. Please try again.<br />n");
}
?>
</body>
</html>
various routines exist
for reading/writing files
simplest is file, which
reads a file into an array
of strings (one per line)

Word ladder in PHP
8
 <html>
 <head>
 <title>Word Ladder Challenge</title>
 <?php
 $dictionary = file("words5.txt");
 $start = $dictionary[rand(0, count($dictionary)-1)];
 $end = $dictionary[rand(0, count($dictionary)-1)];
 ?>
 </head>
 <body>
 <div style="text-align:center">
 <h2>Dave's Word Ladder Challenge</h2>
 <p>Create a word ladder between <b> <?php print($start); ?> </b>
 and <b> <?php print($end); ?> </b>
 <form name="ladderForm"
 action="http://empirical.cs.creighton.edu/~davereed/ladderCheck.php"
 method="post">
 <textarea name="ladder" rows=10 cols=8 wrap="virtual"></textarea>
 <br /><br />
 <input type="hidden" name="start" value="<?php print($start); ?>">
 <input type="hidden" name="end" value="<?php print($end); ?>">
 <input type="submit" value="Submit Ladder">
 </form>
 </div>
 </body>
 </html>
ladder.php contains start
of game:
• PHP displays start &
end words
• static HTML gives form
with text area & submit
button

Word ladder in PHP
9
 <html>
 <head>
 <title>Word Ladder Challenge</title>
 <?php
 function binsearch($needle, $haystack)
 {
 $high = count($haystack)-1;
 $low = 0;
 while ($low <= $high){
 $middle = floor(($high + $low) / 2);
 if (trim($haystack[$middle]) == trim($needle)){
 return true;
 }
 else if (trim($haystack[$middle]) < trim($needle)){
 $low = $middle+1;
 }
 else{
 $high = $middle-1;
 }
 }
 return false;
 }
 function LetterDiff($word1, $word2)
 {
 $diffCount = 0;
 for ($z = 0; $z < strlen(word1); $z++) {
 if ($word1{$z} != $word2{$z}) {
 $diffCount++;
 }
 }
 return $diffCount;
 }
 ?>
 </head>
ladderCheck.php page
• defines functions for
checking a ladder
• static HTML gives form
with text area & submit
button

10
 <body>
 <div style="text-align:center">
 <h2>Dave's Word Ladder Challenge</h2>
 <?php
 $dictionary = file("words5.txt");
 $start = trim($_POST['start']);
 $end = trim($_POST['end']);
 $ladder = trim($_POST['ladder']);
 $ladderArr = preg_split("/[ns]+/", $ladder);
 if ($start != $ladderArr[0]) {
 print("INVALID LADDER: starting word should be $start<br />");
 }
 else if ($end != $ladderArr[count($ladderArr)-1]) {
 print("INVALID LADDER: ending word should be $end<br />");
 }
 else {
 $OK = true;
 for ($i = 1; $i < count($ladderArr) and $OK; $i++) {
 if (!binsearch($ladderArr[$i], $dictionary)) {
 print("INVALID LADDER: ".$ladderArr[$i]." is not a legal word.<br />");
 $OK = false;
 }
 else if (LetterDiff($ladderArr[$i], $ladderArr[$i-1]) != 1) {
 print("INVALID LADDER: ".$ladderArr[$i]." is not connected to" .
 $ladderArr[$i-1].".<br />");
 $OK = false;
 }
 }
 if ($OK) {
 print("$ladder is a valid ladder. Congratulations!<br />");
 }
 }
 ?>
 <form name="ladderForm"
 action="http://empirical.cs.creighton.edu/~davereed/ladder.php" method="post">
 <input type="submit" value="Play Again?">
 </form>
 </div></body></html>
rest of ladderCheck.php
• gets data from form
elements
• verifies the correctness
of the ladder

Standalone PHP
11
 <?php
 $emailDB = file("email.txt");
 $person = $_POST['person'];
 print("Search results for: " . $person . "<br /><br />n");
 $found = false;
 for ($i = 0; $i < count($emailDB); $i+=2) {
 if ($person == "" ||
 strpos("?".strtolower($emailDB[$i]), strtolower($person))) {
 $entry1 = $emailDB[$i];
 $entry2 = $emailDB[$i+1];
 print("$entry1: <a href='mailto:$entry2'>" .
 "$entry2</a><br />n");
 $found = true;
 }
 }
 if (!$found) {
 print("No matching names were found. Please try again.<br />n");
 }
 ?>
previous examples have shown how PHP code can be nested in HTML
 browsers don't really require HTML, HEAD, BODY tags
 if no static content in the page, can ignore HTML elements
 PHP output text will be treated as the body of a default Web page

Another example: file uploading
12
the HTML file input element allows the user to browse for a file
<input type="file" name="ELEMENT_NAME">
 once the user selects a file, can use a submit button to call a CGI or PHP
program to process that file
<html>
<head>
<title>Simple File Uploader</title>
</head>
<body>
<form name="uploader" action="http://empirical.cs.creighton.edu/~davereed/upload.php"
enctype="multipart/form-data" method="post">
Select file for uploading: <input type="file" name="userfile">
<br /><br />
<input type="submit" value="Upload File">
</form>
</body>
</html>

PHP file manipulations
13
 <?php
 $BASEDIR = "/var/www/davereed/files/";
 if (!file_exists($BASEDIR.$_FILES['userfile']['name'])) {
 move_uploaded_file($_FILES['userfile']['tmp_name'],
 $BASEDIR.$_FILES['userfile']['name']);
 print("File uploaded successfully");
 }
 else {
 print("File already exists - no upload performed.");
 }
 ?>
PHP provides extensive support for file/directory manipulation
$_FILES[$FORM_ELE_NAME]['name'] original name of the file uploaded via
the specified form input element
$_FILES[$FORM_ELE_NAME]['tmp_name'] temporary name of the file where it
is uploaded onto the server
move_uploaded_file($_FILES[$FORM_ELE_NAME]['tmp_name'], $FILE_PATH_NAME)
copies uploaded file to specified loc.

Robust file uploading
<html>
<head>
<title>Simple File Uploader</title>
</head>
<body>
<form name="uploader" action="http://empirical.cs.creighton.edu/~davereed/upload.php"
enctype="multipart/form-data" method="post">
<table>
<tr><td>Enter your user name:
<td><input type="text" name="userID" size=10 value="">
<tr><td>Select file for uploading:
<td><input type="file" name="userfile">
</table>
<input type="submit" value="Upload File">
</form>
</body>
</html>
14
could utilize other PHP features to make file uploading more robust
 allow multiple students to submit same assignment
 each student specifies a user name, file is uploaded into a subdirectory

Robust file uploading
15
 <?php
 $userID = $_POST['userID'];
 $BASEDIR = "/var/www/davereed/files/";
 $_FILES['userfile']['name'] = explode(' ', $_FILES['userfile']['name']);
 $_FILES['userfile']['name'] = implode('_', $_FILES['userfile']['name']);
 if (IsSet($userID)) {
 $BASEDIR = $BASEDIR.$userID."/";
 if (!file_exists($BASEDIR)) {
 mkdir($BASEDIR, 755);
 }
 }
 if (!file_exists($BASEDIR.$_FILES['userfile']['name'])) {
 move_uploaded_file($_FILES['userfile']['tmp_name'],
 $BASEDIR.$_FILES['userfile']['name']);
 print("File uploaded successfully");
 }
 else {
 print("File already exists - no upload performed.");
 }
 ?>
get the user ID from text box
replace ' ' with '_'
in file name
if user ID is entered,
extend path & create
directory if deosn't
already exist

Homework submission program
16
 Joel van Brandwijk has extended this program to create a generic homework
submission utility
 student interface is password driven
 connects with Active Directory to verify password for given user name
 student can select among current classes and assignments
 course/assignment info is stored in an SQL database, accessed via PHP
 student can specify multiple files, even structure into subdirectories for uploading
 instructor interface is also password driven
 checks database to make sure a legit instructor, then checks password
 instructor can add/remove class, add/remove students, add/remove assignments
 info is stored in SQL database, accessed via PHP
 instructor can download submissions to local computer for grading
empirical.cs.creighton.edu/submissions

Example: email redirection
17
most Web sites give visitor option of sending feedback
 can be accomplished using mailto: link
<a href=mailto:davereed@creighton.edu>Feedback?</a>
potential problem: not all client computers are email-enabled
 can instead use a PHP program as a front-end for email
 user enters address, subject, message
 PHP program receives & bundles these pieces into an email message, sends on
 if desired, can be used for anonymous email redirection (no return address supplied)

<?php function show_form($email="",$message="",$subject="") { ?>
<h2>Send Me an E-mail</h2>
<form action="http://empirical.cs.creighton.edu/~davereed/email.php"
 method="post">
Your E-mail address:<br>
<input type=text name=email size=30 value="<?php print($email); ?>"><br>
The Subject:<br>
<input type=text name=subject size=30 value="<?php print($subject); ?>"><br>
Your Message:<br>
<textarea rows=10 cols=50 name=message><?php print($message); ?></textarea><br>
<input type=submit value="Send E-mail">
</form>
<?php }
.
.
.
18
this part of the page
defines a function for
generating the input
page

(cont.)
19
 $email = $_POST['email'];
 $subject = $_POST['subject'];
 $message = $_POST['message'];
 if (!isset($email) or !isset($message)) {
 show_form();
 }
 else {
 if (empty($message)) {
 print("Please write something and resend.");
 show_form($email,$message,$subject);
 }
 else {
 if (empty($email)) {
 $email="anonymous";
 }
 if (empty($subject)) {
 $subject="stuff";
 }
 $sent = mail( "davereed@creighton.edu", $subject, $message, "From: $email" );
 if ($sent) {
 print("<H1>Your Message Has Been Sent.</H1>");
 }
 else {
 print("<p>The server was unable to send your mail.");
 }
 }
 }
 ?>
if no inputs to page (not called from
form), show input page
if message field is empty, warn user
and show the input page again
if email or subject fields are empty,
give default values
send the email message and
report status

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