How to use ASP.NET with "Redirect after POST" pattern? [Edited]

Question

I'm trying to implement Redirect After Post for the first time in ASP.NET. Assuming my business objects may take several seconds to a minute to complete, in what order, and what syntax do I use?

For example:

1. User POST's

2. Server issues Server.Transfer or Response.Redirect

3. Server does something that takes a minute or two Thread.Sleep

What is the best way to handle this type of situation?

Answer 1

From what I can see you need to do:

1. User POSTs form to server script
2. Server does something that takes a minute or two using Thread.Sleep
3. Server issues a Response.Redirect

However, the obvious drawbacks here are that the user is kept waiting whilst the server does some work (two minutes is a long delay period, they may well assume that something has gone wrong), and possibly you might hit a HTTP request time out on the browser.

In terms of code, it's pretty straightforward:

1. This is a standard <FORM METHOD="POST"> code
2. Do whatever you need to do, can't see why you would need Thread.Sleep at the moment; wouldn't you want to redirect to happen as soon as your server side processing has completed?
3. Call Response.Redirect("mypage.aspx") to perform the GET

Does that help?

Answer 2

In this case, it is probably best to just stick with Response.Redirect() so that the user's client is issued a redirect, rather than Server.Transfer() which performs a purely server-side redirect to a different context.

Regarding the process which requires the user to wait, you may want to use some sort of asynchronous implementation where the time-consuming operation is placed in a background thread; meanwhile the user, instead of waiting on a blank loading screen, is given Response.Redirect() to a "Processing" page that polls the server for completion of the current operation and updates the user. For added polish, consider implementing something like Facebook's image uploader which overlays a progress bar in the corner of the screen while the user continues normal use of the website.