Correlating stateless HTTP requests
HTTP requests are stateless, meaning that each request is self-contained and contains no information that associates it with any other request, even when made by the same browser. You can see the problem this creates by opening two browser windows and filling out the form with the same name but different ages and number of years, simulating two users with the same name.
The only information the server has to work with is the data in the form and it has no way to figure out that these are requests from different users, so the users see each other’s data, and any other data created by users with the same name, as shown in Figure 13.2.
Figure 13.2: The effect of stateless requests
Most applications are stateful, and that means the server has to be able to correlate requests so that the application can reflect past actions in future responses. In the case of the example, this would allow the application to show just the requests...
