fix(download): fix scheme determination behind reverse proxies

internal/routes/download.go

@@ -104,9 +104,18 @@ func getPublicUrl(r *http.Request, subpath string) string {
 		Host: r.Host,
 		Path: path.Join("public", subpath),
 	}
-	newURL.Scheme = "http"
+	newURL.Scheme = determineScheme(r)
-	if r.TLS != nil {
-		newURL.Scheme = "https"
-	}
 	return newURL.String()
 }
+
+func determineScheme(r *http.Request) string {
+	if proto := r.Header.Get("X-Forwarded-Proto"); proto != "" {
+		return proto
+	}
+
+	if r.TLS != nil {
+		return "https"
+	}
+
+	return "http"
+}