Custom xdg protocol handling?

[RowenStipe]

I'm attempting to install a piece of DJ software called Serato DJ Lite for reverse engineering purposes. I can get the software to install and run using sys-wineas the runner. The problem I'm running into is that Serato DJ Lite requires a sign-in token that the application receives from a website using a custom protocol seratodjlite://authorisedcallback&state=[USER_TOKEN_HERE]&flow_params={"entry"%3A"app_djlite"} but xdg doesn't know how to send that information. I've been able to find out how to make a .desktop file and setup xdg to handle the protocol with it, but it only seems to launch a new instance of the program and doesn't properly authorize.