After a POST, should I do a 302 or a 303 redirect?
A common scenario for a web app is to redirect after a POST that modifies the database. Like redirecting to the newly created database object after the user creates it.
It seems like most web apps use 302 redirects, but 303 seems to be the correct thing to do according to the specification if you want the url specified in the redirect to be fetched with GET. Technically, with a 302, the browser is supposed to fetch the specified url with the same method that the original url was fetched with, which would be POST. Most browsers don't do that though.
302 - http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.3
303 - http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.4
So should I be using 302 or 303?
Answer
The correct one is 303.
I use it and haven't found any compatibility problems with UAs newer than Netscape 4 (1998, released 17 years ago).
If you use 302, you're risking that UA will re-send POST to the new URL instead of switching to GET.
Still, if you're worried about HTTP/1.0 clients (which don't support vhosts and probably won't be able to access your page anyway) then you should include HTML with link to the new page in body of the 303 response (web servers like Apache do that already).