OTA Via HTTP Stream via WiFi from 3rd party App

As part of a larger project I'm trying to update firmware BIN file on a ESP8266 from an external app. I already have a window App I have written that the ESP8266 sends their IP and MAC address to so I have a list of these to use. My plan is to select the BIN file via my APP and send it via HTTP to the ESP .

Based on all the all the examples I can find are either use a web browser to upload, or check on a HTTP server, neither of these would work for me.

Has anyone come across a way of sending the BIN file via HTTP from and external App?

Thanks in advance

Brian