Nginx config to use X-Accel-Redirect to transfer (reproxy) data from Remote servers

gistfile1.nginxconf

location ~* ^/internal_redirect/(.*?)/(.*) {
    internal;

    # If you use variables in proxy pass you need to
    # tell nginx how to resolve your host
    # otherwise you will get 502 errors
    # you could also use google 8.8.8.8
    resolver 172.16.0.23;

    proxy_buffering off;
    proxy_set_header Content-Length ""; 
    proxy_set_header Cookie ""; 

    proxy_hide_header x-amz-request-id;
    proxy_hide_header x-amz-meta-uid;
    proxy_hide_header x-amz-id-2;
    proxy_hide_header x-amz-meta-mode;
    proxy_hide_header x-amz-meta-mtime;
    proxy_hide_header x-amz-meta-gid;
    proxy_hide_header x-amz-version-id;
    proxy_hide_header accept-ranges;

    # Do not touch local disks when proxying
    # content to clients
    proxy_method GET;
    proxy_pass_request_body off;
    proxy_max_temp_file_size 0;

    set $download_host $1; 
    set $download_uri $2; 

    set $download_url http://$download_host/$download_uri;

    add_header x-by "$instance_id:s3";

    proxy_pass $download_url;
  }