(How) can one implement a rich.Prompt using a textual.widgets.Input?

[mrossinek]

I am writing an application which provides both, a CLI (using rich) and a TUI (using textual). This application provides various commands, some of which can require user interaction while they are executed. This brings me to the use case that I would like to be able to replace a rich.Prompt object (which gets triggered during the CLI) with a textual.widgets.Input workflow when this command is triggered from the TUI. However, I am having a hard time realizing this.

I have tried to create a minimal code example to show how far I have gotten and attached it below:

import argparse

from rich.prompt import Confirm, PromptBase
from textual.app import App
from textual.widgets import Input, Static


class TextualPrompt(PromptBase):
    tui = None

    @classmethod
    def get_input(cls, console, prompt, password, stream=None):
        inp = Input(value="test")
        cls.tui.mount(inp)
        inp.focus()
        # TODO: how can I await the Input.Submitted event here to return its result?


class AskCommand:
    def __init__(self, prompt=Confirm):
        self.prompt = prompt

    def execute(self):
        return self.prompt.ask("Do you love Textualize?")


class PromptApp(App):
    BINDINGS = [("a", "ask", "Ask")]

    def compose(self):
        yield Static("Hello from textual!")

    def on_input_submitted(self, event):
        """TODO."""
        event.sender.remove()
        return event.value

    async def action_ask(self):
        TextualPrompt.tui = self
        ask = AskCommand(TextualPrompt)
        res = ask.execute()
        if res:
            await self.mount(Static("Awesome! Make sure to star our Github repo!"))
        else:
            await self.mount(Static("Let us know how we can improve!"))


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("interface", choices=["cli", "tui"])

    args = parser.parse_args()

    if args.interface == "cli":
        ask = AskCommand()
        print(ask.execute())
    elif args.interface == "tui":
        PromptApp().run()

The TODO marker in TextualPrompt.get_input is what is causing me the most headaches.
On top of that, I wonder how/if I could use await within that method, but this requires the method to be declared as async which leads to a RuntimeWarning because the get_input method is never awaited. I am not quite sure how I am supposed to handle this because I would need to mark every method as async if I propagate the await down into the call of ask.execute()...

Any pointers/ideas/help is welcome 🙂

[willmcgugan]

I think what you would need to do is have an app that accepts the input, then call self.exit(result) in the on_input_submitted method.

That way you can return MyApp().run() from your prompt method.

[mrossinek]

Hm I see 🤔 Maybe my example had been reduced a bit too much because I actually want the app to do more than just prompt i.e. it should persist after this particular command finished.

Is there a way to nest apps? If so, this might work. But even then I would need to wait for the app to exit before the get_input method can return, right?

---

I did also try playing around with making TextualPrompt inherit from both PromptBase and Input because this would allow me to implement on_input_submitted on that class directly. But this is proving rather difficult as one might imagine..

[mrossinek]

After quite some tinkering I think I have found a way to make this work. Looks like there are multiple key aspects:

1. I need to create a separate asyncio task for my binding action to make sure the main App event loop does not get blocked
2. I can unmount my Input widget upon on_input_submitted
3. I can use App.is_mounted(widget) to check whether or not my input object has been unmounted during my get_input method

I am posting the code below in case you have some suggestions on how it might be improved further:

import argparse
import asyncio

from rich.prompt import Confirm, InvalidResponse
from textual.app import App
from textual.widgets import Input, Static


class TextualPrompt(Confirm):
    tui = None

    async def __call__(self, *, default=..., stream=None):
        while True:
            self.pre_prompt()
            prompt = self.make_prompt(default)
            value = await self.get_input(self.console, prompt, self.password, stream=stream)
            if value == "" and default != ...:
                return default
            try:
                return_value = self.process_response(value)
            except InvalidResponse as error:
                self.on_validate_error(value, error)
                continue
            else:
                return return_value

    @classmethod
    async def get_input(cls, console, prompt, password, stream=None):
        inp = Input()
        await cls.tui.mount(inp)

        inp.focus()

        while cls.tui.is_mounted(inp):
            await asyncio.sleep(0)

        return inp.value


class AskCommand:
    def __init__(self, prompt=Confirm):
        self.prompt = prompt

    def execute(self):
        return self.prompt.ask("Do you love Textualize?")


class PromptApp(App):
    BINDINGS = [("a", "ask", "Ask")]

    def compose(self):
        yield Static("Hello from textual!")

    def on_input_submitted(self, event):
        event.sender.remove()

    def action_ask(self):
        asyncio.create_task(self._async_action_ask())

    async def _async_action_ask(self):
        TextualPrompt.tui = self
        ask = AskCommand(TextualPrompt)
        res = await ask.execute()
        if res:
            await self.mount(Static("Awesome! Make sure to star our Github repo!"))
        else:
            await self.mount(Static("Let us know how we can improve!"))
        self.refresh()


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("interface", choices=["cli", "tui"])

    args = parser.parse_args()

    if args.interface == "cli":
        ask = AskCommand()
        res = ask.execute()
        if res:
            print("Awesome! Make sure to star our Github repo!")
        else:
            print("Let us know how we can improve!")
    elif args.interface == "tui":
        PromptApp().run()