How to limit_req depending if the requests has a REFERER or not.

[Valentin V. Bartenev]

On Wednesday 06 June 2012 03:31:03 Valentin V. Bartenev wrote:
> On Wednesday 06 June 2012 02:33:09 Joseph Cabezas wrote:
> > I have something like this... I need to be able to apply three different
> > limit_req depending:
> > 
> > a.) If the referer to click.php is domain.com ... apply zone1
> > b.) If there is some other referer apply zone2 on click.php
> > c.) If there is no referer apply zone3 on click.php
> > 
> >   location /click.php { limit_req zone=one;  proxy_pass http://backend; }
[...]
> 
>      map $invalid_referer $zone1 {
>          0  1;
>          1  '';
>      }
> 
>      map $invalid_referer $zone2 {
>          0  '';
>          1  $is_referer;
>      }
> 
>      map $invalid_referer $zone3 {
>          0  '';
>          1  $no_referer;
>      }
[...]

Oops, Ruslan Ermilov pointed out to me that the "false" value of 
$invalid_referer is an empty string, not "0".

http://nginx.org/r/valid_referers

Well, then the correct config example is as follows:

 http {

     map $http_referer $zone3 {
         default  1;
         ~^.      '';
     }

     map $zone3 $zone2 {
         default  $invalid_referer;
         1        '';
     }

     map $invalid_referer $zone1 {
         default  1;
         1        '';
     }

     limit_req_zone $zone1 zone=zone1:128k rate=50r/s;
     limit_req_zone $zone2 zone=zone2:128k rate=10r/s;
     limit_req_zone $zone3 zone=zone3:128k rate=3r/s;

     server {
         valid_referers domain.com;

         location /click.php {
             limit_req zone=zone3 burst=12;
             limit_req zone=zone2 burst=10 nodelay;
             limit_req zone=zone1 burst=100 nodelay;
             ...

 wbr, Valentin V. Bartenev