Transcript Tim Berners-Lee

HTTP
By Mychal Hess, Dee Chow, and
Riley Barnes
History HTTP

Tim Berners-Lee he implemented the HTTP
protocol in 1990 at the European Center for HighEnergy Physics in Geneva, Switzerland.

He invented a new protocol for the computers to
speak as they exchanged hypermedia documents.
This allows the communication between http clients
with http servers.

The HTTP protocol uses the concept of reference
provided by the Universal Resource Identifier (URI)
as a location (URL) or name (URN), for indicating
the resource on which a method is to be applied.
HTTP

HTTP stands at the very core of the World Wide
Web. According to the HTTP 1.0 specification,
HTTP is an application-level protocol with the
lightness and speed necessary for distributed,
collaborative, hypermedia information systems.

It is stateless: After the server has responded to
the client's request, the connection between
client and server is dropped and forgotten.
What Does it Look Like?
Request Line
Response Line
Allows communication of HTTP Client with HTTP Server through a browser
How It Works

Client initiates process

Sender process consists of three stages:

Request Line

Header Information Stage

Body of Request Stage
Request Stage

Client sends out request to receiver

Request stage contains three parts

First part is called the method

Three main methods of request:

Get method: Receive information from server

Head method: Ask for information about server or particular file

Post method: Allows data to be sent from sender to receiver
Request Stage
Second part of request stage sends out
Uniform Resource Locator (URL) to server
 This includes name of server
 Followed by name of file
 Followed by the parameter information

http://www.espn.com/nba/clubhouse?team=por
Protocol
Server Name
File Name
Parameter Info
•Third Part sends out HTTP version that the server needs to reply with
Header Info and Body





The second stage header information is sent
The sender gives its user agent, i.e. what
browser it’s using (Internet explorer, Mozilla,
etc.)
Gives its preference for document types, such as
pictures in JPEG, GIF, or PJPEG Format
Lastly, internet cookies are exchanged during this
stage in the process
Third and final stage contains the body of the
request
Response Line
Version of HTTP
 Code which indicates success of request
 200= Successful
 400= Bad Request
 403= Access Denied
 404= File not found
 402= Payment Required
 Text indicating meaning of code

Response Line (Cont.)
Response Headers
 Version of HTTP
 Content Type: HTML, Mp3, JPEG
 Bytes

Response Line (Cont.)

Body eg: Map
Starts Over
Stateless Protocol
Cookies
Cookies are short pieces of data used by
web servers to help identify web users.
 Cookies are embedded in the HTML
information flowing back and forth
between the user's computer and the
servers.
 Cookies make use of user-specific
information transmitted by the Web server
onto the user's computer so that the
information might be available for later
access by itself or other servers.

Process of Cookie
Two-stage process
 First the cookie is stored in the user's
computer.
 Second stage the cookie is automatically
transferred from the user's machine to a
Web server.

Dangers of Cookies
In most cases, not only does the storage
of personal information into a cookie go
unnoticed, so does access to it. Web
servers automatically gain access to
relevant cookies whenever the user
establishes a connection to them
 Some people may find this invasive to
their privacy, but usually the use of this
information is harmless
