textField.addKeyDownListener sends request on every keypress?

Flow
1

I have a textField with a regular keyDown listener.
The event fires when it should, but browser sends a request on every keypress.
That doesn’t seem right.

@Route(value="/test")
public class Test extends VerticalLayout {

    public Test() {

    	var textField = new TextField("TextField");

    	textField.addKeyDownListener(Key.ESCAPE, event -> {
    		System.out.println("ESC:\n" + event.toString());
        });

        add(textField);

    }

}

Vaadin 24.5.0.beta5, Firefox 130.0.1, Windows 10

2

That is indeed how the listener is implemented, the key check happens on the server: flow/flow-server/src/main/java/com/vaadin/flow/component/KeyEventListener.java at 818d28490a7c74763987e9761b22d5b1071b1653 · vaadin/flow · GitHub

3

Doesn’t mean it is right though. :smile:
Seems like it should’ve been filtered both on the client-side and the server-side.

Not sure how to feel about this one. Vaadin is a chatty app anyway, so maybe I’m overthinking this, but it just feels wrong to generate pointless traffic.

I guess I’ll use the element-level filtered event handler instead.
That also seems wrong; using a low-level API when a high-level API is available, but in this case I think it is the least wrong.

4

Why do you think that this could cause issues? We have many key listeners and there is no problem with that.

5

As I said, maybe I’m overthinking this, but I just assume less traffic is better.

I have not observed any problems, other than me wasting time debugging why I got this unexpected traffic.

6

Yes. Sometimes so. That is why in TextField there are the value change modes, so that you can control it. But that applies only the value change event.