Security in Computing 5th Edition by Shari Lawrence Pfleeger, Charles P Pfleeger, Jonathan Margulies

Exercise 24

The HTTP protocol is by definition stateless, meaning that it has no mechanism for “remembering” data from one interaction to the next. (a) Suggest a means by which you can preserve state between two HTTP calls. For example, you may send the user a page of books and prices matching a user’s query, and you want to avoid having to look up the price of each book again once the user chooses one to purchase. (b) Suggest a means by which you can preserve some notion of state between two web accesses many days apart. For example, the user may prefer prices quoted in euros instead of dollars, and you want to present prices in the preferred currency next time without asking the user.

Step 1 of 2

Preserving State and Notion for HTTP calls

a) HTTP is stateless protocol. Stateless means that it contains no record of data that is transmitted from one interface to the other. The state of two HTTP calls can be preserved.

The HTTP calls are made from the side of server or from the side of client. When a server sends some data containing two data fields, the client may view once both fields and next time it is possible that client may use only one data field. So on the side of server, space is occupied by the saving space.

So, saving space on the server side can be used to preserve the state between two calls of the HTTP protocols.