ipn/localapi: implement LoginInteractive via localapi

Updates: #4738

Signed-off-by: Joel Cressy <joel@jtcressy.net>

ipn/localapi/localapi.go

@@ -109,6 +109,8 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		h.serveStatus(w, r)
 	case "/localapi/v0/logout":
 		h.serveLogout(w, r)
+	case "/localapi/v0/login-interactive":
+		h.serveLoginInteractive(w, r)
 	case "/localapi/v0/prefs":
 		h.servePrefs(w, r)
 	case "/localapi/v0/ping":
@@ -343,6 +345,20 @@ func (h *Handler) serveStatus(w http.ResponseWriter, r *http.Request) {
 	e.Encode(st)
 }
 
+func (h *Handler) serveLoginInteractive(w http.ResponseWriter, r *http.Request) {
+	if !h.PermitWrite {
+		http.Error(w, "login access denied", http.StatusForbidden)
+		return
+	}
+	if r.Method != "POST" {
+		http.Error(w, "want POST", 400)
+		return
+	}
+	h.b.StartLoginInteractive()
+	w.WriteHeader(http.StatusNoContent)
+	return
+}
+
 func (h *Handler) serveLogout(w http.ResponseWriter, r *http.Request) {
 	if !h.PermitWrite {
 		http.Error(w, "logout access denied", http.StatusForbidden)