cloud proxy/ port forwarding server in flask.

I am looking for someone to provide a flask server that acts as the man in the middle for http and tcp requests from an android phone to a raspberry pi. This server functions as an alternative to port forwarding by providing features similar to the [login to view URL] website but obviously much simpler. Basically my project works over my local network and I just want it to work on the internet by providing different ip addresses inside my python code.