Method __call__

nextpy/backend/event.py:157–194

Pass arguments to the handler to get an event spec. This method configures event handlers that take in arguments. Args: *args: The arguments to pass to the handler. Returns: The event spec, containing both the function and args. Raises:

(self, *args: Var)

        return getattr(self.fn, BACKGROUND_TASK_MARKER, False)

    def __call__(self, *args: Var) -> EventSpec:
        """Pass arguments to the handler to get an event spec.

        This method configures event handlers that take in arguments.

        Args:
            *args: The arguments to pass to the handler.

        Returns:
            The event spec, containing both the function and args.

        Raises:
            TypeError: If the arguments are invalid.
        """
        # Get the function args.
        fn_args = inspect.getfullargspec(self.fn).args[1:]
        fn_args = (Var.create_safe(arg) for arg in fn_args)

        # Construct the payload.
        values = []
        for arg in args:
            # Special case for file uploads.
            if isinstance(arg, FileUpload):
                return arg.as_event_spec(handler=self)

            # Otherwise, convert to JSON.
            try:
                values.append(Var.create(arg, _var_is_string=type(arg) is str))
            except TypeError as e:
                raise TypeError(
                    f"Arguments to event handlers must be Vars or JSON-serializable. Got {arg} of type {type(arg)}."
                ) from e
        payload = tuple(zip(fn_args, values))

        # Return the event spec.
        return EventSpec(
            handler=self, args=payload, event_actions=self.event_actions.copy()
        )


class EventSpec(EventActionsMixin):