reflex/pynecone/app.py
Elijah Ahianyo e8387c8e26
Fix Event chaining in the on_load event handler return not working (#773)
* Fix Event chaining in the on_load event handler return not working

* added async tests

* addressed comments
2023-04-06 22:26:43 -07:00

606 lines
19 KiB
Python

"""The main Pynecone app."""
import inspect
from typing import Any, Callable, Coroutine, Dict, List, Optional, Tuple, Type, Union
from fastapi import FastAPI, UploadFile
from fastapi.middleware import cors
from socketio import ASGIApp, AsyncNamespace, AsyncServer
from pynecone import constants
from pynecone.base import Base
from pynecone.compiler import compiler
from pynecone.compiler import utils as compiler_utils
from pynecone.components.component import Component, ComponentStyle
from pynecone.config import get_config
from pynecone.event import Event, EventHandler
from pynecone.middleware import HydrateMiddleware, Middleware
from pynecone.model import Model
from pynecone.route import (
DECORATED_ROUTES,
catchall_in_route,
catchall_prefix,
get_route_args,
verify_route_validity,
)
from pynecone.state import DefaultState, Delta, State, StateManager, StateUpdate
from pynecone.utils import format, types
# Define custom types.
ComponentCallable = Callable[[], Component]
Reducer = Callable[[Event], Coroutine[Any, Any, StateUpdate]]
class App(Base):
"""A Pynecone application."""
# A map from a page route to the component to render.
pages: Dict[str, Component] = {}
# A list of URLs to stylesheets to include in the app.
stylesheets: List[str] = []
# The backend API object.
api: FastAPI = None # type: ignore
# The Socket.IO AsyncServer.
sio: Optional[AsyncServer] = None
# The socket app.
socket_app: Optional[ASGIApp] = None
# The state class to use for the app.
state: Type[State] = DefaultState
# Class to manage many client states.
state_manager: StateManager = StateManager()
# The styling to apply to each component.
style: ComponentStyle = {}
# Middleware to add to the app.
middleware: List[Middleware] = []
# Event handlers to trigger when a page loads.
load_events: Dict[str, Union[EventHandler, List[EventHandler]]] = {}
def __init__(self, *args, **kwargs):
"""Initialize the app.
Args:
*args: Args to initialize the app with.
**kwargs: Kwargs to initialize the app with.
"""
super().__init__(*args, **kwargs)
# Get the config
config = get_config()
# Add middleware.
self.middleware.append(HydrateMiddleware())
# Set up the state manager.
self.state_manager.setup(state=self.state)
# Set up the API.
self.api = FastAPI()
self.add_cors()
self.add_default_endpoints()
# Set up CORS options.
cors_allowed_origins = config.cors_allowed_origins
if config.cors_allowed_origins == [constants.CORS_ALLOWED_ORIGINS]:
cors_allowed_origins = "*"
# Set up the Socket.IO AsyncServer.
self.sio = AsyncServer(
async_mode="asgi",
cors_allowed_origins=cors_allowed_origins,
cors_credentials=config.cors_credentials,
max_http_buffer_size=config.polling_max_http_buffer_size,
ping_interval=constants.PING_INTERVAL,
ping_timeout=constants.PING_TIMEOUT,
)
# Create the socket app. Note event endpoint constant replaces the default 'socket.io' path.
self.socket_app = ASGIApp(self.sio, socketio_path="")
# Create the event namespace and attach the main app. Not related to any paths.
event_namespace = EventNamespace("/event", self)
# Register the event namespace with the socket.
self.sio.register_namespace(event_namespace)
# Mount the socket app with the API.
self.api.mount(str(constants.Endpoint.EVENT), self.socket_app)
def __repr__(self) -> str:
"""Get the string representation of the app.
Returns:
The string representation of the app.
"""
return f"<App state={self.state.__name__}>"
def __call__(self) -> FastAPI:
"""Run the backend api instance.
Returns:
The backend api.
"""
return self.api
def add_default_endpoints(self):
"""Add the default endpoints."""
# To test the server.
self.api.get(str(constants.Endpoint.PING))(ping)
# To upload files.
self.api.post(str(constants.Endpoint.UPLOAD))(upload(self))
def add_cors(self):
"""Add CORS middleware to the app."""
self.api.add_middleware(
cors.CORSMiddleware,
allow_credentials=True,
allow_methods=["*"],
allow_headers=["*"],
allow_origins=["*"],
)
async def preprocess(
self, state: State, event: Event
) -> Optional[Union[StateUpdate, List[StateUpdate]]]:
"""Preprocess the event.
This is where middleware can modify the event before it is processed.
Each middleware is called in the order it was added to the app.
If a middleware returns a delta, the event is not processed and the
delta is returned.
Args:
state: The state to preprocess.
event: The event to preprocess.
Returns:
An optional state to return.
"""
for middleware in self.middleware:
out = await middleware.preprocess(app=self, state=state, event=event)
if out is not None:
return out
async def postprocess(
self, state: State, event: Event, delta: Delta
) -> Optional[Delta]:
"""Postprocess the event.
This is where middleware can modify the delta after it is processed.
Each middleware is called in the order it was added to the app.
If a middleware returns a delta, the delta is not processed and the
delta is returned.
Args:
state: The state to postprocess.
event: The event to postprocess.
delta: The delta to postprocess.
Returns:
An optional state to return.
"""
for middleware in self.middleware:
out = await middleware.postprocess(
app=self, state=state, event=event, delta=delta
)
if out is not None:
return out
def add_middleware(self, middleware: Middleware, index: Optional[int] = None):
"""Add middleware to the app.
Args:
middleware: The middleware to add.
index: The index to add the middleware at.
"""
if index is None:
self.middleware.append(middleware)
else:
self.middleware.insert(index, middleware)
def add_page(
self,
component: Union[Component, ComponentCallable],
route: Optional[str] = None,
title: str = constants.DEFAULT_TITLE,
description: str = constants.DEFAULT_DESCRIPTION,
image=constants.DEFAULT_IMAGE,
on_load: Optional[Union[EventHandler, List[EventHandler]]] = None,
meta: List[Dict] = constants.DEFAULT_META_LIST,
script_tags: Optional[List[Component]] = None,
):
"""Add a page to the app.
If the component is a callable, by default the route is the name of the
function. Otherwise, a route must be provided.
Args:
component: The component to display at the page.
route: The route to display the component at.
title: The title of the page.
description: The description of the page.
image: The image to display on the page.
on_load: The event handler(s) that will be called each time the page load.
meta: The metadata of the page.
script_tags: List of script tags to be added to component
Raises:
TypeError: If an invalid var operation is used.
"""
# If the route is not set, get it from the callable.
if route is None:
assert isinstance(
component, Callable
), "Route must be set if component is not a callable."
route = component.__name__
# Check if the route given is valid
verify_route_validity(route)
# Apply dynamic args to the route.
self.state.setup_dynamic_args(get_route_args(route))
# Generate the component if it is a callable.
try:
component = component if isinstance(component, Component) else component()
except TypeError as e:
message = str(e)
if "BaseVar" in message or "ComputedVar" in message:
raise TypeError(
"You may be trying to use an invalid Python function on a state var. "
"When referencing a var inside your render code, only limited var operations are supported. "
"See the var operation docs here: https://pynecone.io/docs/state/vars "
) from e
raise e
# Add meta information to the component.
compiler_utils.add_meta(
component, title=title, image=image, description=description, meta=meta
)
# Add script tags if given
if script_tags:
component.children.extend(script_tags)
# Format the route.
route = format.format_route(route)
# Add the page.
self._check_routes_conflict(route)
self.pages[route] = component
if on_load:
self.load_events[route] = on_load
def _check_routes_conflict(self, new_route: str):
"""Verify if there is any conflict between the new route and any existing route.
Based on conflicts that NextJS would throw if not intercepted.
Raises:
ValueError: exception showing which conflict exist with the route to be added
Args:
new_route: the route being newly added.
"""
newroute_catchall = catchall_in_route(new_route)
if not newroute_catchall:
return
for route in self.pages:
route = "" if route == "index" else route
if new_route.startswith(f"{route}/[[..."):
raise ValueError(
f"You cannot define a route with the same specificity as a optional catch-all route ('{route}' and '{new_route}')"
)
route_catchall = catchall_in_route(route)
if (
route_catchall
and newroute_catchall
and catchall_prefix(route) == catchall_prefix(new_route)
):
raise ValueError(
f"You cannot use multiple catchall for the same dynamic route ({route} !== {new_route})"
)
def add_custom_404_page(
self,
component,
title=None,
image=None,
description=None,
meta=constants.DEFAULT_META_LIST,
):
"""Define a custom 404 page for any url having no match.
If there is no page defined on 'index' route, add the 404 page to it.
If there is no global catchall defined, add the 404 page with a catchall
Args:
component: The component to display at the page.
title: The title of the page.
description: The description of the page.
image: The image to display on the page.
meta: The metadata of the page.
"""
title = title or constants.TITLE_404
image = image or constants.FAVICON_404
description = description or constants.DESCRIPTION_404
component = component if isinstance(component, Component) else component()
compiler_utils.add_meta(
component, title=title, image=image, description=description, meta=meta
)
froute = format.format_route
if (froute(constants.ROOT_404) not in self.pages) and (
not any(page.startswith("[[...") for page in self.pages)
):
self.pages[froute(constants.ROOT_404)] = component
if not any(
page.startswith("[...") or page.startswith("[[...") for page in self.pages
):
self.pages[froute(constants.SLUG_404)] = component
def compile(self, force_compile: bool = False):
"""Compile the app and output it to the pages folder.
If the config environment is set to production, the app will
not be compiled.
Args:
force_compile: Whether to force the app to compile.
"""
for render, kwargs in DECORATED_ROUTES:
self.add_page(render, **kwargs)
# Get the env mode.
config = get_config()
if config.env != constants.Env.DEV and not force_compile:
print("Skipping compilation in non-dev mode.")
return
# Update models during hot reload.
if config.db_url is not None:
Model.create_all()
# Empty the .web pages directory
compiler.purge_web_pages_dir()
# Compile the root document with base styles and fonts.
compiler.compile_document_root(self.stylesheets)
# Compile the theme.
compiler.compile_theme(self.style)
# Compile the pages.
custom_components = set()
for route, component in self.pages.items():
component.add_style(self.style)
compiler.compile_page(route, component, self.state)
# Add the custom components from the page to the set.
custom_components |= component.get_custom_components()
# Compile the custom components.
compiler.compile_components(custom_components)
self.state.convert_handlers_to_fns()
async def process(
app: App, event: Event, sid: str, headers: Dict, client_ip: str
) -> Union[StateUpdate, List[StateUpdate]]:
"""Process an event.
Args:
app: The app to process the event for.
event: The event to process.
sid: The Socket.IO session id.
headers: The client headers.
client_ip: The client_ip.
Returns:
The state update(s) after processing the event.
"""
# Get the state for the session.
state = app.state_manager.get_state(event.token)
formatted_params = format.format_query_params(event.router_data)
# Pass router_data to the state of the App.
state.router_data = event.router_data
# also pass router_data to all substates
for _, substate in state.substates.items():
substate.router_data = event.router_data
state.router_data[constants.RouteVar.QUERY] = formatted_params
state.router_data[constants.RouteVar.CLIENT_TOKEN] = event.token
state.router_data[constants.RouteVar.SESSION_ID] = sid
state.router_data[constants.RouteVar.HEADERS] = headers
state.router_data[constants.RouteVar.CLIENT_IP] = client_ip
# Preprocess the event.
pre = await app.preprocess(state, event)
if pre is not None and not isinstance(pre, List):
return pre
# Apply the event to the state.
updates = pre if pre else await state.process(event)
app.state_manager.set_state(event.token, state)
updates = updates if isinstance(updates, List) else [updates]
# Postprocess the event.
post_list = []
for update in updates:
post = await app.postprocess(state, event, update.delta) # type: ignore
post_list.append(post) if post else None
if post_list:
return [StateUpdate(delta=post) for post in post_list]
# Return the update.
return updates
async def ping() -> str:
"""Test API endpoint.
Returns:
The response.
"""
return "pong"
def upload(app: App):
"""Upload a file.
Args:
app: The app to upload the file for.
Returns:
The upload function.
"""
async def upload_file(files: List[UploadFile]):
"""Upload a file.
Args:
files: The file(s) to upload.
Returns:
The state update after processing the event.
Raises:
ValueError: if there are no args with supported annotation.
"""
token, handler = files[0].filename.split(":")[:2]
for file in files:
file.filename = file.filename.split(":")[-1]
# Get the state for the session.
state = app.state_manager.get_state(token)
handler_upload_param: Tuple = ()
# get handler function
func = getattr(state, handler.split(".")[-1])
# check if there exists any handler args with annotation UploadFile or List[UploadFile]
for k, v in inspect.getfullargspec(
func.fn if isinstance(func, EventHandler) else func
).annotations.items():
if (
types.is_generic_alias(v)
and types._issubclass(v.__args__[0], UploadFile)
or types._issubclass(v, UploadFile)
):
handler_upload_param = (k, v)
break
if not handler_upload_param:
raise ValueError(
f"`{handler}` handler should have a parameter annotated with one of the following: List["
f"pc.UploadFile], pc.UploadFile "
)
# check if handler supports multi-upload
multi_upload = types._issubclass(handler_upload_param[1], List)
event = Event(
token=token,
name=handler,
payload={handler_upload_param[0]: files if multi_upload else files[0]},
)
update = await state.process(event)
return update
return upload_file
class EventNamespace(AsyncNamespace):
"""The event namespace."""
# The application object.
app: App
def __init__(self, namespace: str, app: App):
"""Initialize the event namespace.
Args:
namespace: The namespace.
app: The application object.
"""
super().__init__(namespace)
self.app = app
def on_connect(self, sid, environ):
"""Event for when the websocket disconnects.
Args:
sid: The Socket.IO session id.
environ: The request information, including HTTP headers.
"""
pass
def on_disconnect(self, sid):
"""Event for when the websocket disconnects.
Args:
sid: The Socket.IO session id.
"""
pass
async def on_event(self, sid, data):
"""Event for receiving front-end websocket events.
Args:
sid: The Socket.IO session id.
data: The event data.
"""
# Get the event.
event = Event.parse_raw(data)
# Get the event environment.
assert self.app.sio is not None
environ = self.app.sio.get_environ(sid, self.namespace)
assert environ is not None
# Get the client headers.
headers = {
k.decode("utf-8"): v.decode("utf-8")
for (k, v) in environ["asgi.scope"]["headers"]
}
# Get the client IP
client_ip = environ["REMOTE_ADDR"]
# Process the events.
updates = await process(self.app, event, sid, headers, client_ip)
# Emit the event.
for update in updates:
await self.emit(str(constants.SocketEvent.EVENT), update.json(), to=sid) # type: ignore
async def on_ping(self, sid):
"""Event for testing the API endpoint.
Args:
sid: The Socket.IO session id.
"""
# Emit the test event.
await self.emit(str(constants.SocketEvent.PING), "pong", to=sid)