This makes sense as it was created to handle self-hosted ONCE products without Kamal. However, we don’t really need all of that if we already run Rails with Kamal. We handle TLS either directly with Traefik or Cloudflare, and offload storage concerns to CDNs.
When you serve a file from Rails (e.g. with send_file in a controller), an X-Sendfile header is set. This header is processed by Rack::Sendfile and depending on the proxy, it’s served with the proxy or by this Rack middlewear.