API to paste from clipboard for extensions?

Desktop
1

Is there an API that lets extensions paste from the clipboard? Barring that, is there an API to send keyboard events (so I could simulate paste with Shift + Insert)? I’m looking for a way to send a paste event so whatever is in the clipboard gets put into the currently focused input.

2

You could use the global.stage variable and call Clutter.Stage.get_key_focus() on it the get the currently focused element. Assuming that actor is an editable Clutter.Text or St.Entry, you can use St.Clipboard.get_text() and set the text property.

3

Hmmm, that doesn’t seem to work. get_key_focus almost always returns MetaStage. I also tried creating a key press event, but neither method works:

const event = Clutter.Event.new(Clutter.EventType.KEY_PRESS);
event.set_flags(Clutter.EventFlags.FLAG_SYNTHETIC);
event.set_key_code(97);

// All of gnome crashes with
// Clutter:ERROR:../clutter/clutter/clutter-seat.c:627:clutter_seat_handle_event_post: 'CLUTTER_IS_INPUT_DEVICE (device)' should be TRUE
// Bail out! Clutter:ERROR:../clutter/clutter/clutter-seat.c:627:clutter_seat_handle_event_post: 'CLUTTER_IS_INPUT_DEVICE (device)' should be TRUE
event.put();

// JS fails with JS ERROR: GLib.Error g-invoke-error-quark: Could not locate clutter_stage_event: 'clutter_stage_event': /usr/lib/x86_64-linux-gnu/mutter-8/libmutter-clutter-8.so.0: undefined symbol: clutter_stage_event
global.stage.get_key_focus().event(event, false);
4

You probably don’t want to make events, that’s really for the Shell to do. It also won’t do much if nothing has key focus anywhere.

For me, global.stage.get_key_focus() works if it’s something in the Shell that has focus. You can’t introspect the internal state of arbitrary applications from a GNOME Shell extension, if that’s what you’re trying to do. Those might be GTK, Qt, Windows applications being run by Wine, etc.

5

You can’t introspect the internal state of arbitrary applications from a GNOME Shell extension

Ah, that is what I’m trying to do (sort of). I just want to force a paste into whatever application currently has focus (I’m writing a clipboard manager). Is that not supported?

6

I suppose you could try simulating the keyboard events for pasting, maybe with a Clutter.VirtualDevice or there may be a way to do it with Mutter. I’ve never tried to do that before though, so I don’t know if just simulating the keypresses will engage the result.

7

That could work, do you know how I get an instance of the virtual keyboard?

8

Clutter.Seat.create_virtual_device(). You can look through js/ui/keyboard.js for hints.

1 Like
9

Holy freakin’ smokes, this actually works!!! Thank you!

const VirtualKeyboard = Clutter.get_default_backend()
  .get_default_seat()
  .create_virtual_device(Clutter.InputDeviceType.KEYBOARD_DEVICE);

const eventTime = Clutter.get_current_event_time() * 1000;
VirtualKeyboard.notify_keyval(
  eventTime,
  Clutter.KEY_Shift_L,
  Clutter.KeyState.PRESSED,
);
VirtualKeyboard.notify_keyval(
  eventTime,
  Clutter.KEY_Insert,
  Clutter.KeyState.PRESSED,
);
VirtualKeyboard.notify_keyval(
  eventTime,
  Clutter.KEY_Insert,
  Clutter.KeyState.RELEASED,
);
VirtualKeyboard.notify_keyval(
  eventTime,
  Clutter.KEY_Shift_L,
  Clutter.KeyState.RELEASED,
);
1 Like
10

I’m glad that worked out :slightly_smiling_face:

11

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