NGINX Proxy_Pass remove url substring

It's really basic and simple. Just add /path/ part to proxy_pass and nginx will replace locations prefix with that path. You need to replace /string_1/ with /, so do it:

location /string_1/ {
    proxy_pass  http://internal_host:port/;
}

I found the way to rewrite the proxy_pass URL:

  location  /string_1/   {  

    if ($request_uri ~* "/string_1/(.*)") { 
            proxy_pass  http://internal_host:port/$1;
    }   

  }

Regards,

@pcamacho