why should I use question mark ?

[Maxim Dounin]

Hello!

On Fri, Jul 06, 2012 at 10:44:15PM +0800, 任晓磊 wrote:

> I want rewrite a uri to itself without querystring, I tried
> rewrite .+ $uri permanent;
> but it rewrite to the original uri, with querystring unstripped.
> 
> After googled, I try
> rewrite .+ $uri? permanent;
> and it works correctly. 
> 
> But why?

Because it's how it's expected to work.  By default the "rewrite" 
directive preserves query string, and even if you write arguments 
in a replacement string - they are added before original query 
string which is still preserved.  Trailing question mark is an 
explicit flag that you don't want to preserve query string.

http://nginx.org/r/rewrite

Maxim Dounin