This document discusses various web application development topics including sending emails with PHP, handling file uploads, using JavaScript with HTML, understanding HTTP headers, using date and time functions, making a login page, using cookies and sessions to store data on the server-side and client-side. It provides code examples for tasks like setting and accessing cookies and sessions, uploading files, and sending emails. It also compares key differences between JavaScript and PHP.

1. UNIT - 5
WEB APPLICATION, COOKIES AND SESSIONS

2. Sending email
• Syntax: mail(to, subject, body, [headers]);
• Eg:
$to = 'email@example.com';
$subject = 'This is the subject';
$body = 'This is the body. It goes over multiple lines.';
mail ($to, $subject, $body);
• Subject line cannot include ‘n’.
• Body should not exceed 70 characters.
$body = wordwrap($body, 70);

3. Example

4. Handling file uploads
• Steps
• Things to be considered:
• PHP- correct settings
• Temporary storage directory
• Final storage directory
• Allowing for file uploads:
php.ini

5. • Uploading files with PHP:
<form enctype="multipart/form-data" action="script.php"
method="post">
<input type="hidden" name="MAX_FILE_SIZE" value="30000" />
File <input type="file" name= "upload" />
• $_FILES: name, type, size, tmp_name, error.
• move_uploaded_file (temporary
_filename,/path/to/destination/filename);

6. Example

7. PHP and Javascript
• Javascript with HTML code can be done in 2 ways:
• Inline
• External file
• Inline Javascript
<script type="text/javascript">
// A c t u a l J a v a S c r i p t c o d e.
</script>
• External Javascript
<script type="text/javascript" src="somefile.js"></script>

8. Comparison
JAVASCRIPT PHP
Client side program Server side program
Can detect the size of popup, browser window and
image mouse over
Cannot detect
Cannot interact with MySQL Can interact with MySQL
Cannot generate PHP code Can dynamically generate Javascript
.js .php
OOP approach Procedural and OOP approach
In HTML: <script type=“text/javascript”>
</script>
<?php
?>

9. Understanding HTTP headers
• the uploaded images are being stored in the ‘uploads’ directory.
• the images cannot be viewed directly in the Web browser using either
of the following:
http://www.example.com/uploads/ image.png or
<img src="image.png" />
• create a proxy script in PHP.
http://www.example.com/proxy.php? image=image.png
or
<img src="proxy.php?image=image.png" />

10. Proxy script

11. Header()
• used to redirect the Web browser from the current page to another.
• syntax: header(header string);
• header ('Location: http://www.example.com/page.php’);
• To send a file:
header("Content-Type:application/pdfn");
header ("Content-Disposition: attachment;
filename="somefile.pdf"n");
header ("Content-Length: 4096n");

12. Date and time function
• Date_default_timezone_set(tz);
• Checkdate();
• Date(format, [timestamp]);

13. Date() function
formatting

14. • Eg:
echo date('F j, Y'); // January 26, 2011
echo date('H:i'); // 23:14
echo date('D'); // Sat
• mktime(): mktime (hour, minute, second, month, day, year);
• getdate():
$today = getdate( );
echo $today['month']; // October

15. getdate() array

16. Making a Login page

17. Making the login functions
• header ('Location: http://www. example.com/page.php');
exit( );
• 3 step process:
• Email address
• Password
• Email address and password

18. Using cookies
• a way for a server to store information on the user’s machine.

19. Setting cookies
• Setcookie(name, value, expiration, path, host, secure, httponly);

20. Accessing cookies

21. Deleting cookies

22. Session
• Data stored on the server.
• Advantages of session over cookies:
• Secure
• More data
• Without cookies
• Advantages of cookies over session:
• Easier
• Less of server
• More time

23. Setting the session
• Session_start()

24. • Accessing the session: $_SESSION
• Deleting the session:
• Unset($_SESSION[‘var’]);
• $_SESSION=array();
• Session_destroy();

25. Improving session security
• Session ID and session data
• HTTP_USER_AGENT
$_SESSION[‘agent’]=md5($_SERVER[‘HTTP_USER_AGENT’]);