proxy_pass based on (possibly changed) $host

[Johan Bergström]

Hello,

On Jan 28, 2009, at 12:02 , Igor Sysoev wrote:

> On Wed, Jan 28, 2009 at 02:52:24AM -0800, Dave Bailey wrote:
>
>> Hi,
>>
>> I am porting a lighttpd module that I wrote to nginx.  I am new to
>> nginx.  I would like to know if it is possible to choose the
>> proxy_pass backend from the Host header within a server.  In  
>> lighttpd,
>> this is possible by:
>>
>> $SERVER["socket"] == ":80" {
>>  $HTTP["host"] == "bar.foo.com" {
>>    proxy-core.backends = ( "10.0.0.1:80" )
>>  }
>>  $HTTP["host"] == "baz.foo.com" {
>>    proxy-core.backends = ( "10.0.0.2:80" )
>>  }
>> }
>
> However, the better:
>
>    server {
>        listen   80;
>        server_name   bar.foo.com;
>
>        location  / {
>            proxy_pass  http://10.0.0.1:80;
>        }
>    }
>
>    server {
>        listen   80;
>        server_name   baz.foo.com;
>
>        location  / {
>            proxy_pass  http://10.0.0.2:80;
>        }
>    }
>
>
>> The module that I am porting to nginx will sometimes update the Host
>> header such that a different proxy backend should be chosen.  For
>> example, a request from a particular IP address to http:// 
>> bar.foo.com/
>> might be updated such that its Host header changes from bar.foo.com  
>> to
>> baz.foo.com, and thus it is served by the 10.0.0.2:80 backend.  Is
>> there a way to specify a relationship between $host and proxy_pass in
>> nginx.conf within the same server { ... }?
>
>    map $remote_addr  $back1 {
>        default       10.0.0.1:80;
>        192.168.1.1   10.0.0.2:80;
>        192.168.1.5   10.0.0.2:80;
>    }
>
>    server {
>        listen   80;
>        server_name   bar.foo.com;
>
>        location  / {
>            proxy_pass  http://$back1$request_uri;
>        }
>    }
>
>    map $remote_addr   $back2 {
>        default        10.0.0.2:80;
>        192.168.10.1   10.0.0.1:80;
>        192.168.10.5   10.0.0.1:80;
>    }
>
>    server {
>        listen   80;
>        server_name   baz.foo.com;
>
>        location  / {
>            proxy_pass  http://$back2$request_uri;
>        }
>    }

This is very similar to how i have things set up; but this map is  
rather static. I "solved" this by using memcached as "map", a simple  
FastCGI application written in C doing the lookup which returns the  
backend to use. My question is if this map thing somehow could be  
expanded to something of a more dynamic nature?

>
>
>
> -- 
> Igor Sysoev
> http://sysoev.ru/en/
>