Session management or session tracking is a very important topic in web application development. This is due to the fact that HTTP, the language of the web, is stateless. A web server by default does not know if an HTTP request comes from a first time user or from someone who has visited it before.
For example, a webmail application requires its users to log in before they can check their emails. However, once a user types in the correct user name and password, the application should not prompt the user to log in again to access different parts of the application. The application needs to remember which users have successfully logged in. In other words, it must be able to manage user sessions.
This chapter ...