51 lines
1.5 KiB
Python
51 lines
1.5 KiB
Python
"""Middleware to hydrate the state."""
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from __future__ import annotations
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import dataclasses
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from typing import TYPE_CHECKING
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from reflex_base import constants
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from reflex_base.event import Event, get_hydrate_event
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from reflex.middleware.middleware import Middleware
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from reflex.state import BaseState, StateUpdate, _resolve_delta
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if TYPE_CHECKING:
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from reflex.app import App
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@dataclasses.dataclass(init=True)
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class HydrateMiddleware(Middleware):
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"""Middleware to handle initial app hydration."""
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async def preprocess(
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self, app: App, state: BaseState, event: Event
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) -> StateUpdate | None:
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"""Preprocess the event.
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Args:
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app: The app to apply the middleware to.
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state: The client state.
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event: The event to preprocess.
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Returns:
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An optional delta or list of state updates to return.
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"""
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# If this is not the hydrate event, return None
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if event.name != get_hydrate_event(state):
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return None
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# Clear client storage, to respect clearing cookies
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state._reset_client_storage()
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# Mark state as not hydrated (until on_loads are complete)
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setattr(state, constants.CompileVars.IS_HYDRATED, False)
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# Get the initial state.
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delta = await _resolve_delta(state.dict())
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# since a full dict was captured, clean any dirtiness
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state._clean()
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# Return the state update.
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return StateUpdate(delta=delta, events=[])
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