Connection state

[benedikt-bartscher]

import asyncio
import datetime

import reflex as rx
from reflex.state import SessionStatusEnum


class State(rx.State):
    count: int = 0
    first_event: datetime.datetime = datetime.datetime.now()
    # events: list[tuple[SessionStatusEnum, datetime.datetime]] = []

    # def on_load(self) -> None:
    #     last_status = self.events[-1][0] if self.events else None
    #
    #     if self.status == last_status:
    #         return
    #
    #     new_event = (self.status, datetime.datetime.now())
    #     self.events.append(new_event)

    def increment(self) -> None:
        self.count += 1

    @rx.var
    def last_event(self) -> datetime.datetime:
        return self._session_status.last_event

    @rx.var
    def status(self) -> SessionStatusEnum:
        return self._session_status.status

    @rx.background
    async def background(self) -> None:
        while True:
            await asyncio.sleep(1)
            async with self:
                if self.status == SessionStatusEnum.DISCONNECTED:
                    print("Session disconnected")
                    break
                self.count += 1
            print(f"background loop: {self.count}")


def index() -> rx.Component:
    return rx.fragment(
        rx.button("Increment", on_click=State.increment),  # pyright: ignore[reportUnknownMemberType]
        rx.button("Start Background", on_click=State.background),  # pyright: ignore[reportUnknownMemberType]
        rx.text(State.count),
        rx.text(f"session_id: {State.router.session.session_id}"),
        rx.text(f"client_token: {State.router.session.client_token}"),
        rx.text(f"last_event: {State.last_event}"),
        rx.text(f"first_event: {State.first_event}"),
        rx.text(f"status: {State.status}"),
        # rx.text("events:"),
        # rx.foreach(State.events, lambda event: rx.text(f"{event[0]}: {event[1]}")),
    )


app = rx.App()
app.add_page(
    index,
    # on_load=State.on_load,
)

[Lendemor]

I missed that PR before.

I kinda like the idea of having a SessionStatus field.

Do you think you could later update this PR to use the change from #3388 once they are merged ?

[benedikt-bartscher]

@Lendemor no worries, it wasn't really finished yet. I will rebase once your PR is merged.

[Lendemor]

#3388 PR is merged.

Feel free to ping me when this one is ready for review.

[benedikt-bartscher]

@Lendemor I rebased it and added a small use example in the issue description.
The functionality is ready for review, but I'll need to adjust some tests which do not expect the new session state to be there (with #2429 fewer tests would need to be adjusted).

[Lendemor]

@benedikt-bartscher Got it, I'll review whenever the PR is marked as ready 👍

[masenf]

i started looking at the test changes, but i think if we just avoid sending these new fields in the delta then the tests can stay the way they are.

[benedikt-bartscher]

Anything else missing here?

[masenf]

hitting a couple of issues with this

1. all states seem to share the same _session_status; i think this needs to be declared as a pydantic.PrivateAttr so each instance gets its own copy
2. the RECONNECTED state does not seem to "stick". it shows up once when the initial reconnection happens, but then immediately changes to CONNECTED again, so detecting the reconnected state is not really possible if there is an on_load or some other event processed before the handler that is supposed to check the status.

We might need some integration tests for this feature.

[masenf]

Needs a test case and the above issues addressed (accidentally clicked approve earlier)

[benedikt-bartscher]

Thanks for looking into this!

1. is fixed in 39b5658
2. yes, I noticed this as well. I will drop reconnected for now

[Lendemor]

Marking this as draft until ready for review.