reflex/pynecone/middleware/hydrate_middleware.py
2023-03-16 14:59:27 -07:00

57 lines
1.9 KiB
Python

"""Middleware to hydrate the state."""
from __future__ import annotations
from typing import TYPE_CHECKING, Optional
from pynecone import constants
from pynecone.event import Event, EventHandler, get_hydrate_event
from pynecone.middleware.middleware import Middleware
from pynecone.state import Delta, State
from pynecone.utils import format
if TYPE_CHECKING:
from pynecone.app import App
class HydrateMiddleware(Middleware):
"""Middleware to handle initial app hydration."""
def preprocess(self, app: App, state: State, event: Event) -> Optional[Delta]:
"""Preprocess the event.
Args:
app: The app to apply the middleware to.
state: The client state.
event: The event to preprocess.
Returns:
An optional state to return.
"""
if event.name == get_hydrate_event(state):
route = event.router_data.get(constants.RouteVar.PATH, "")
if route == "/":
load_event = app.load_events.get(constants.INDEX_ROUTE)
elif route:
load_event = app.load_events.get(route.lstrip("/"))
else:
load_event = None
if load_event:
if isinstance(load_event, list):
for single_event in load_event:
self.execute_load_event(state, single_event)
else:
self.execute_load_event(state, load_event)
return format.format_state({state.get_name(): state.dict()})
def execute_load_event(self, state: State, load_event: EventHandler) -> None:
"""Execute single load event.
Args:
state: The client state.
load_event: A single load event to execute.
"""
substate_path = format.format_event_handler(load_event).split(".")
ex_state = state.get_substate(substate_path[:-1])
load_event.fn(ex_state)