What is Cookie Technology?

Hi Everybody,
The cookie technology relates to the use of HTTP cookies or web cookies, as they are called, by the websites. A cookie is a piece of text that is sent by a server to a web client, and returned by the client, each time it uses that server. Usually a cookie is a text message that is less than 255 characters long. The cookie technology is used for authentication of the website users, session tracking as also for maintaining certain information about the users.

Why is Cookie Technology Used?

Cookies serve as the means to identify a particular user. Once a user logs in to a website, a cookie can be made to associate with the user's login information. For the subsequent visits by that user to the same website, the cookie can let know the website that the user is authenticated. Thus, the user is saved from the monotonous tasks of filling in the login information each time he visits the website.

The second purpose of using the cookie technology is to differentiate between website users. The information pertaining to the user and his preferences can be held in the cookies. This makes it possible for the websites to provide personalization to the users. Based on the preferences of a particular user, websites can bring about a personalization in the presentation of the website and also its functionality. Many websites offer the authenticated users with a facility to customize the web pages and obtain a personalized look and feel in the website.

How does the Cookie Technology Work?
The transfer of web pages between a server and a browser happens by means of the Hypertext Transfer Protocol (HTTP). When a user types in a URL in the address bar of a browser, the browser takes it and sends a request to the server, asking for the web page that was specified by the user.
Next, the server sends the page requested by the browser, in the form of an HTTP response. The response is sent as a packet of text that may contain a statement asking the browser to store cookies. This is done by means of a statement, "set-cookie: name =value". The browser is asked to store the value-string in 'name' and return it to the server during any of the further requests made to it.
During any subsequent request made to the same server, even while requesting a different web page from that server, the browser sends back the cookie value to server. The server identifies this information and fulfills the request, without having the user to perform the authentication process again.