uPortal2/backend/internal/auth/handler.go

package auth

import (
	"net"
	"net/http"
	"strings"
	"time"
)

// ExtractIP resolves the client's IP address from a request, accounting for the
// reverse proxy in front of the backend. When the proxy forwards the original
// address (X-Forwarded-For / X-Real-IP) the leftmost value is used; otherwise it
// falls back to the connection's remote address.
func ExtractIP(r *http.Request) string {
	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
		ips := strings.Split(xff, ",")
		return strings.TrimSpace(ips[0])
	}

	if realIP := r.Header.Get("X-Real-IP"); realIP != "" {
		return realIP
	}

	ip, _, err := net.SplitHostPort(r.RemoteAddr)
	if err != nil {
		return r.RemoteAddr
	}
	return ip
}

func SigninSetup(w http.ResponseWriter, cookieName, cookieValue string, expiresAt time.Time, secure bool) {
	maxAge := expiresAt.Sub(time.Now().UTC())
	http.SetCookie(w, &http.Cookie{
		Name:     cookieName,
		Value:    cookieValue,
		Path:     "/",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		Secure:   secure,
		MaxAge:   int(maxAge.Seconds()),
	})
}

func SignoutCleanup(w http.ResponseWriter, cookieName string, secure bool) {
	http.SetCookie(w, &http.Cookie{
		Name:     cookieName,
		Value:    "",
		Path:     "/",
		HttpOnly: true,
		Secure:   secure,
		SameSite: http.SameSiteLaxMode,
		MaxAge:   -1,
	})
}