Simple arithmetics in nginx config

[agentzh]

On Mon, Nov 28, 2011 at 4:11 PM, mennanov <nginx-forum at nginx.us> wrote:
>
> location ~ /i/(.*)\.jpg {
>            set $folder $1-($1%100);
>            try_files /i/$folder/$1.jpg =400;
>        }
>
> but of course it does not work due to syntax error.
>

The standard "set" directive does not support arithmetic operations at
all. But it's an ideal use case for our ngx_lua module:

    location ~ /i/(.*)\.jpg {
       set_by_lua $folder 'return ngx.var[1] - (ngx.var[1] % 100)';
       try_files /i/$folder/$1.jpg =400;
    }

See http://wiki.nginx.org/HttpLuaModule for details.

Regards,
-agentzh