RequireLogin middleware

main.go

var sessionManager = scs.NewCookieManager("...")

func RequireLogin(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		session := sessionManager.Load(r)

		userID, err := session.GetInt("userID")
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
		}

		if userID == 0 {
			http.Redirect(w, r, "/login", http.StatusFound)
			return
		}

		validUser := CheckUserID(userID)
		if !validUser {
			http.Redirect(w, r, "/login", http.StatusFound)
			return
		}

		next.ServeHTTP(w, r)
	})
}

func CheckUserID(userID int) bool {
	// Check your database to make sure the provided ID is valid.
	return true // or false
}