Swagger UI not working behind HTTPS reverse proxy due to mixed content

[wlandgraf (Wagner Landgraf)]

@Kaeswurm_Thomas

However, I would prefer to try solving it by properly configuring the nginx reverse proxy.

Why?
Adding the Forward middleware to the Sparkle/XData server is the way to go, that is exactly what it is for: tell XData it's behind a reverse proxy and properly behave according to the info sent by it.