Question on Rewrite / If statements

[Maxim Dounin]

Hello!

On Fri, Sep 18, 2009 at 10:28:50AM -0500, Resicow wrote:

> Hi Igor,
> 
> Thanks for your response.
> 
> We have lots of virtual hosting domains setup, using $host to point
> to the correct root directory. This way we can add / subtract
> domains without touching the nginx config.
> 
> Similar to the "Wildcard Subdomains in a Parent Folder" at
> http://wiki.nginx.org/NginxVirtualHostExample
> 
> This has been working perfectly for us, however we want to stop
> leeching by checking the HTTP Referer.
> 
> Since the configuration is "virtual", only the $host variable
> actually "knows" the name of the vhost.
> 
> So we want to test to ensure that either $http_referer contains
> $host (using an if statement), or using the HTTP Referer module with
> something like this:
> 
> valid_referers none blocked $host;
> 
> Can you think of anyway to have nginx test two variables in this
> fashion? Because of our setup, it is not possible to manually enter
> these values in the config file, or manually setup a vhost for each
> domain.

As a workaround you may use something like:

    set $blah "$host:$http_host";

    if ($blah ~ "^([^:]+):\1$") {
        return 403;
    }

Maxim Dounin


> 
> Thanks,
> 
> John
> 
> 
> 
> 
> 
> Igor Sysoev wrote:
> >On Wed, Sep 16, 2009 at 08:03:26PM -0500, Resicow wrote:
> >
> >>Hello,
> >>
> >>I have learned that the http_referer module does *not* support variables.
> >>
> >>I am trying to work around this with if / rewrite statements,
> >>but may have run into the same issue.
> >>
> >>How can I make this work?
> >>
> >>set $myvar mydomain.com;
> >>if ($http_referer ~* $myvar) {
> >>do something
> >>}
> >>
> >>When I run that, it always returns false. However this works:
> >>
> >>if ($http_referer ~* mydomain.com) {
> >>do something
> >>}
> >>
> >>It appears that the if statement doesn't evaluate the variable.
> >>Is there anyway around this?
> >
> >Yes, "if" is ugly hack and it does not evaluate a right part of expression.
> >
> >What task do you want to resolve using $http_referer ?
> >
> >
> 
>