Redirecting from domain.com to www.domain.com keeping GET & POST data

Question

Currently my web site shows the same data if people go to domain.com or www.domain.com.

I would like to set up a redirect so all requests to domain.com will get sent onto www.domain.com. So a user who goes to domain.com will get redirected to www.domain.com. Just like what happens if you go to http://amazon.com/?a=b

I don't want to lose or corrupt any GET or POST data that is sent in the domain.com request.

What is the best way to do this? Should I use a 301 redirect? Will this cause the user's browser to re-send GET/POST data to the www.domain.com URL?

[EDIT] Ok, Zaagmans says redirecting POST transparently to the user is not possible. So lets ignore POST for the moment. How should I redirect with just query string data?

Answer 1

The Redirecting Post Requests article explains this in detail.
A (possible) downside of the proposed 307 redirect is the fact that the browser will alert the user and present an option to proceed or to cancel the request.

Answer 2

Yes. For GETs, you'll need to use a 301, and the browser will need to re-request it. If your GETs are idempotent (and they should be), this won't be a problem. Search engines respect 301s in ways that they don't respect other 30x codes.

I don't know which web server you're using, but there are usually URL rewrite/redirect modules that will handle a lot of this for you.