textual-drivers: Textual's default Drivers, but with more features

[NSPC911]

Hello everyone! I introduce you to textual-drivers. It adds two new functions for use in the driver.

lock_stdin()

It is a context manager that pauses the driver's stdin reader thread, disables all terminal event reporting enabled by Textual, and drains remaining bytes to allow you to send and receive an ANSI sequence.

register_event_handler()

This is the most game-changing of the two. It lets you register a custom Event() class to be sent when a given pattern is received via stdin.

from textual_drivers import BoundedPattern

class DND(Event):
    def __init__(self, data: str) -> None:
        super().__init__()

class Application(App):
    def on_mount(self) -> None:
        driver = self._driver
        driver.register_event_handler(BoundedPattern(start="\x1b]72;", end="\x1b\\"), DND)

Doing this will cause Textual to send the DND event, and it can be handled using @on(DND) or on_dnd!

To make use of this, you can just

uv add textual-drivers

and do this change

- from textual.app import App
+ from textual_drivers import DrivenApp as App

And the rest is automatically handled!

Using this feature, I was able to add proper Drag and Drop support in Textual, something that would not have been possible before. View the full documentation for it at the wiki. You can test it using the latest kitty-nightly version by running

uvx --with textual-drivers python -m textual_drivers.demo.drag_in  # test dragging in
uvx --with textual-drivers python -m textual_drivers.demo.drag_out  # test dragging out

For a real implementation of DNDApp, check NSPC911/rovr#300.

I'm not sure if the base features (lock_stdin and register_event_handler) will be added to Textual, neither do I plan to upstream this as a PR (too big + vibe-coded), so for now, this will be opt-in.