Pass filename and type to backend server


I am trying to upload a file to an nginx server and then have it passed
to the backend server after upload completes. I am able to set it up as
described here ( and see that the file is
being uploaded. However I am not able to get the file name and type to
backend server.
Could someone please tell me if I am missing something here? Any help is
much appreciated.

BTW this question is also at