We're trying to achieve the following story in MVC:
Customer hits a regular action/view page and fills out a form. They click the submit button to post the values back to the controller, which in turn starts a long-running background process.
Customer is redirected to a temporary 'processing - please wait' page. The page uses AJAX to periodically poll for a status update.
When processing has completed, redirect customer to the result page.
KEY REQUIREMENT: If the customer hits the Back button in the browser at step 3, they should return to step 1. We DO NOT want the customer to go to step 2 and we don't want step 2 to appear in the browser history.
How can we achieve the above without the dreaded "Resubmit Posted Values?" message too?
Please note that I'm not looking for a discussion on the pros/cons of polling here. I know it's not the best solution in the world and we may well refactor using Signal R. The story is the important thing for me.