How to debug FastAPI?

[matt-grain]

Hi,

I started to refactor my code (according to the discussion on a multipages application), and I broke something. The even API returns a 500 but there is no trace in the pc.run console.

Only in the browser network tab:

Where is the event POST defined?

[picklelo]

Hmm I think this means an exception is being thrown somewhere within the Pynecone framework (any exception raised directly by your own defined event handlers should show up in the console).

Could you share the relevant code maybe for the SubmitButtonState?

In the next version we will improve transparency and bubble up these errors, currently it is difficult to debug 😕

[matt-grain]

Yeah I finally understood what causes the problem (but not why). due to the refactoring, I have sub-sub-states and that is the issue:

from typing import List, Dict
import pynecone as pc


class ButtonModel(pc.Model, table=False):

    title: str


class AppState(pc.State):
    """The app state."""

    default_field: str


class LocalState(AppState):

    button_state: List[bool] = [False for i in range(10)]

    @pc.var
    def get_buttonmodel(self) -> List[ButtonModel]:
        self.default_field = "break me"
        return [ButtonModel(id=0, title="this is a button which breaks pynecone"), ButtonModel(id=1, title=self.default_field)]


class SubState(LocalState):
    def trigger_fault(self) -> None:
        print("error")


def index():
    return pc.center(
        pc.vstack(
            pc.foreach(LocalState.get_buttonmodel, lambda a_model: display_form(a_model)),
            spacing="1.5em",
            font_size="2em",
        ),
        padding_top="10%",
    )


def display_form(model: ButtonModel):

    return pc.button(model.title, size="lg", on_click=SubState.trigger_fault)


# Add state and page to the app.
app = pc.App(state=AppState)
app.add_page(index)
app.compile()