authentik/internal/outpost/proxy/utils.go

package proxy

import (
	"net"
	"net/http"
)

var xForwardedHost = http.CanonicalHeaderKey("X-Forwarded-Host")

func getHost(req *http.Request) string {
	host := req.Host
	if req.Header.Get(xForwardedHost) != "" {
		host = req.Header.Get(xForwardedHost)
	}
	hostOnly, _, err := net.SplitHostPort(host)
	if err != nil {
		return host
	}
	return hostOnly
}