complete information abot http protocol and www

1. {
The World Wide Web
Architecture
Client (Browser)
Server
Uniform Resource Locator
Web documents
Cookies

2. The WWW is a repository of information that can
be accessed via the internet.
The WWW today is a distributed client/server
service, in which a client using a browser can
access a service using a server. However, the
service provided is distributed over many locations
called sites.
What is?
World Wide Web

3. Architecture of WWW
ARCHITECTURE
World Wide Web

4. Web client (Browser)
World Wide Web

5. server
A computer program or a device that provides functionality for
other programs or devices, called "clients“.
 File server
 Print server
 Network server
Examples:
 Microsoft internet information server
 Apache
World Wide Web

6. URL
World Wide Web

7. <scheme> : //<host> :<port> /<path> ;<parameters>
?<query> #<fragment>
scheme
• The protocol you are using
host
• Host name or ip number
port
• TCP port number that protocol server is using
path
• Path and filename reference of object on server
http://doc.gold.ac.uk/~username/index.html
World Wide Web

8. Web Documents
The documents in the WWW can be grouped into three
broad categories: static, dynamic, and active. The
category is based on the time at which the contents of
the document are determined.
1.Static Documents
2.Dynamic Documents
3.Active Documents
World Wide Web

9. Static document
World Wide Web

10. Dynamic document using CGI
World Wide Web

11. Dynamic document using server-site script
World Wide Web

12. Active document using Java applet
World Wide Web

13. Active document using client-site script
World Wide Web

14. What happened when you click on hyperlink?
1. Determine URL and extract domain name.
2. Use the name server to get IP address (DNS)
3. Make a TCP connect to port 80
4. And send a request for a web page once the server has
accepted to connection.
5. The server send the file and releases the TCP
connection
6. The client displays the document.
World Wide Web

15. Cookies
 Request the browser to store a small data file (cookie) on
the users hard disk.
 Which can serve to identify users only.
 For instance it could contain a key into a database on the
server machine.
 Most browsers nowadays allow you to decide whether or
not you want cookies on your machine.
World Wide Web

17. HTTP
 The Hypertext Transfer Protocol (HTTP) is a
protocol used mainly to access data on the World
Wide Web. HTTP functions as a combination of FTP
and SMTP.
 Request and response protocol

18. HTTP transaction
Hyper Text Transfer Protocol

19. I would like to open a
connection
GET <file location>
Display response
Close connection
OK
Send page or error message
OK
Client Server
HTTP is the set of rules governing the format and content
of the conversation between a Web client and server
An HTTP conversation
Hyper Text Transfer Protocol

20. Request and response messages
Hyper Text Transfer Protocol

21. Request and status lines
Hyper Text Transfer Protocol

22. Methods
Hyper Text Transfer Protocol

23. Hyper Text Transfer Protocol

24. Status codes Hyper Text Transfer Protocol

25. Status codes (continued)
Hyper Text Transfer Protocol

26. Header format
Hyper Text Transfer Protocol
 General headers
 Request headers
 Response headers
 Entity headers

27. General headers
Hyper Text Transfer Protocol

28. Request headers Hyper Text Transfer Protocol

29. Response headers
Hyper Text Transfer Protocol

30. Entity headers
Hyper Text Transfer Protocol

31. Example 1
Hyper Text Transfer Protocol

32. Example 2
Hyper Text Transfer Protocol

33. Hyper Text Transfer Protocol