[eluser]obiron2[/eluser]
Hi guys, long time no post.
I am in the process of reviewing some IT systems for our company (retail EPOS) and one of them was entirely internet browser based (running in kiosk mode so no access to history)
One of the things that really impressed me was that if the browser crashed or the machine was turned off, the appliation recovered from the state it was in.
For example. You start a new transactions and enter an item code and the system returns the price - (easy: just an ajax query to the database and inject a new div into the DOM). If the browser crashed and you recover, the till shows the transaction with the item entered.
Whenever I have written ajax apps, the browser history only remembers the contents of the page when it was first served up and not any changes you have made with javascript.
How would you go about the design concept for this 'stateful' application. Would you need to write the order object data back with each ajax call, or just call an object method for each action and re-serve the whole of the object details to the browser with each ajax call. I am pretty sure they are not storing anything other than a session cookie locally, but I am interested to know whether you would try to hold the object data browser side or if not how you would keep the object server side and would you use generic controllers to intercept and interpret the ajax calls as the user changes the object in the browser (add, remove lines, select payment method etc..)
Also, they managed to print to a receipt printer directly from the browser application without windows popping up the print dialog box. Any idea how you would do this?
Thanks
Obiron
