Using nginx as forward proxy for bad connection locations

ngnix.conf

worker_processes  1;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    keepalive_timeout  300;

    gzip  on;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml;
    gzip_proxied    no-store no-cache private expired auth;
    gzip_comp_level 8;

    tcp_nodelay on;
    tcp_nopush on;
    sendfile on;

    server {
        listen       8080;

        try_files @direct @auth;

        location @direct {
            set $auth "NO";

            if ($http_cookie ~* "AUTH_COOKIE=([a-z0-9]+)(?:;|$)") {
              set $auth $1;
            }

            resolver 8.8.8.8;
            if ($auth !~ "NO") {
              proxy_pass http://$http_host$uri$is_args$args;
            }
        }

        location @auth {
          auth_basic           "You should enter credetials";
          auth_basic_user_file htpasswd;

          resolver 8.8.8.8;
          proxy_pass http://$http_host$uri$is_args$args;

        }

        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}