I have a web application having three pages, one is login page, second is contact page, and third is chat page. The natural sequence to traverse is one to second and from second to third.
Login (using our web service) is required to open second and third page. Now we have a requirement that we want to open third page directly from a third party application.
So, suppose if third page is requested from browser and on the same browser login (using first page) has been made. Then we need to directly show the third page otherwise show the user first page i.e. login page.
The requirement is similar as required facebook page can be opened by clicking an link from gmail page, if facebook user has done login, he can see the desired page directly.