fix: Return error on pinging closed connections (#373)

Author: kylecarbs

wsnet/dial.go

@@ -176,6 +176,9 @@ func (d *Dialer) Close() error {
 
 // Ping sends a ping through the control channel.
 func (d *Dialer) Ping(ctx context.Context) error {
+	if d.ctrl.ReadyState() == webrtc.DataChannelStateClosed || d.ctrl.ReadyState() == webrtc.DataChannelStateClosing {
+		return webrtc.ErrConnectionClosed
+	}
 	// Since we control the client and server we could open this
 	// data channel with `Negotiated` true to reduce traffic being
 	// sent when the RTC connection is opened.

wsnet/dial_test.go

@@ -161,6 +161,29 @@ func TestDial(t *testing.T) {
 			return
 		}
 	})
+
+	t.Run("Disconnect", func(t *testing.T) {
+		connectAddr, listenAddr := createDumbBroker(t)
+		_, err := Listen(context.Background(), listenAddr)
+		if err != nil {
+			t.Error(err)
+			return
+		}
+		dialer, err := DialWebsocket(context.Background(), connectAddr, nil)
+		if err != nil {
+			t.Error(err)
+			return
+		}
+		err = dialer.Close()
+		if err != nil {
+			t.Error(err)
+			return
+		}
+		err = dialer.Ping(context.Background())
+		if err != webrtc.ErrConnectionClosed {
+			t.Error(err)
+		}
+	})
 }
 
 func BenchmarkThroughput(b *testing.B) {