iter states

[benedikt-bartscher]

import asyncio
import datetime

import reflex as rx
from reflex.utils.prerequisites import get_app


class State(rx.State):
    async def invalidate(self) -> None:
        app = get_app()
        async for state in app.modify_states(from_state=self, substate_cls=State):
            pass

    @rx.var
    def time(self) -> str:
        return datetime.datetime.now().strftime("%H:%M:%S")


def index() -> rx.Component:
    return rx.container(
        rx.text(f"Current time: {State.time}"),
        rx.button("Invalidate State", on_click=State.invalidate),
    )


async def invalidate_lifespan() -> None:
    app = get_app()
    while True:
        async for state in app.modify_states(substate_cls=State):
            pass
        await asyncio.sleep(5)


app = rx.App(lifespan_tasks=[invalidate_lifespan])
app.add_page(index)

[benedikt-bartscher]

@masenf do you have any idea if there is a cool way to automatically detect if modify_states was called from an event handler to check for from_state=self for deadlock prevention?

[benedikt-bartscher]

@masenf do you have any idea if there is a cool way to automatically detect if modify_states was called from an event handler to check for from_state=self for deadlock prevention?

We could also add a BaseState.modify_states partial-like method which calls app.modify_states(..., from_state=self) and advise users to use self.modify_states in event handlers

[picklelo]

Sorry for the delay here. I think the changes look good - we need to rebase this onto main and implement it for StateManagerDisk which is becoming the default in 0.7.0

[benedikt-bartscher]

Sorry for the delay here. I think the changes look good - we need to rebase this onto main and implement it for StateManagerDisk which is becoming the default in 0.7.0

No worries, I just implemented it for StateManagerDisk

[picklelo]

Code works well for me. I'll wait for @masenf 's final approval to merge. What was the use case for this?