A pre-built solution is soon to be built-in. For now, see [`RedirectHttp`](https://docs.rs/actix-web-lab/0.16/actix_web_lab/middleware/struct.RedirectHttps.html) from [`actix-web-lab`](https://crates.io/crates/actix-web-lab).
You might have already implemented TLS (using one of the ways mentioned in the example of security section), and have setup your server to listen to port 443 (for HTTPS).