267 lines
11 KiB
Python
267 lines
11 KiB
Python
from __future__ import annotations
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import sys
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import typing
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import warnings
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if sys.version_info >= (3, 10): # pragma: no cover
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from typing import ParamSpec
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else: # pragma: no cover
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from typing_extensions import ParamSpec
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from starlette.datastructures import State, URLPath
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from starlette.middleware import Middleware, _MiddlewareClass
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from starlette.middleware.base import BaseHTTPMiddleware
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from starlette.middleware.errors import ServerErrorMiddleware
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from starlette.middleware.exceptions import ExceptionMiddleware
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from starlette.requests import Request
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from starlette.responses import Response
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from starlette.routing import BaseRoute, Router
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from starlette.types import ASGIApp, ExceptionHandler, Lifespan, Receive, Scope, Send
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from starlette.websockets import WebSocket
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AppType = typing.TypeVar("AppType", bound="Starlette")
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P = ParamSpec("P")
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class Starlette:
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"""
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Creates an application instance.
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**Parameters:**
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* **debug** - Boolean indicating if debug tracebacks should be returned on errors.
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* **routes** - A list of routes to serve incoming HTTP and WebSocket requests.
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* **middleware** - A list of middleware to run for every request. A starlette
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application will always automatically include two middleware classes.
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`ServerErrorMiddleware` is added as the very outermost middleware, to handle
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any uncaught errors occurring anywhere in the entire stack.
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`ExceptionMiddleware` is added as the very innermost middleware, to deal
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with handled exception cases occurring in the routing or endpoints.
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* **exception_handlers** - A mapping of either integer status codes,
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or exception class types onto callables which handle the exceptions.
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Exception handler callables should be of the form
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`handler(request, exc) -> response` and may be either standard functions, or
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async functions.
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* **on_startup** - A list of callables to run on application startup.
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Startup handler callables do not take any arguments, and may be either
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standard functions, or async functions.
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* **on_shutdown** - A list of callables to run on application shutdown.
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Shutdown handler callables do not take any arguments, and may be either
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standard functions, or async functions.
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* **lifespan** - A lifespan context function, which can be used to perform
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startup and shutdown tasks. This is a newer style that replaces the
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`on_startup` and `on_shutdown` handlers. Use one or the other, not both.
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"""
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def __init__(
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self: AppType,
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debug: bool = False,
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routes: typing.Sequence[BaseRoute] | None = None,
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middleware: typing.Sequence[Middleware] | None = None,
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exception_handlers: typing.Mapping[typing.Any, ExceptionHandler] | None = None,
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on_startup: typing.Sequence[typing.Callable[[], typing.Any]] | None = None,
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on_shutdown: typing.Sequence[typing.Callable[[], typing.Any]] | None = None,
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lifespan: Lifespan[AppType] | None = None,
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) -> None:
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# The lifespan context function is a newer style that replaces
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# on_startup / on_shutdown handlers. Use one or the other, not both.
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assert lifespan is None or (
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on_startup is None and on_shutdown is None
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), "Use either 'lifespan' or 'on_startup'/'on_shutdown', not both."
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self.debug = debug
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self.state = State()
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self.router = Router(
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routes, on_startup=on_startup, on_shutdown=on_shutdown, lifespan=lifespan
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)
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self.exception_handlers = (
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{} if exception_handlers is None else dict(exception_handlers)
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)
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self.user_middleware = [] if middleware is None else list(middleware)
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self.middleware_stack: ASGIApp | None = None
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def build_middleware_stack(self) -> ASGIApp:
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debug = self.debug
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error_handler = None
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exception_handlers: dict[
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typing.Any, typing.Callable[[Request, Exception], Response]
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] = {}
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for key, value in self.exception_handlers.items():
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if key in (500, Exception):
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error_handler = value
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else:
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exception_handlers[key] = value
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middleware = (
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[Middleware(ServerErrorMiddleware, handler=error_handler, debug=debug)]
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+ self.user_middleware
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+ [
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Middleware(
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ExceptionMiddleware, handlers=exception_handlers, debug=debug
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)
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]
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)
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app = self.router
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for cls, args, kwargs in reversed(middleware):
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app = cls(app=app, *args, **kwargs)
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return app
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@property
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def routes(self) -> list[BaseRoute]:
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return self.router.routes
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def url_path_for(self, name: str, /, **path_params: typing.Any) -> URLPath:
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return self.router.url_path_for(name, **path_params)
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async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
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scope["app"] = self
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if self.middleware_stack is None:
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self.middleware_stack = self.build_middleware_stack()
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await self.middleware_stack(scope, receive, send)
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def on_event(self, event_type: str) -> typing.Callable: # type: ignore[type-arg]
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return self.router.on_event(event_type) # pragma: nocover
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def mount(self, path: str, app: ASGIApp, name: str | None = None) -> None:
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self.router.mount(path, app=app, name=name) # pragma: no cover
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def host(self, host: str, app: ASGIApp, name: str | None = None) -> None:
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self.router.host(host, app=app, name=name) # pragma: no cover
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def add_middleware(
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self,
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middleware_class: type[_MiddlewareClass[P]],
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*args: P.args,
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**kwargs: P.kwargs,
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) -> None:
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if self.middleware_stack is not None: # pragma: no cover
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raise RuntimeError("Cannot add middleware after an application has started")
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self.user_middleware.insert(0, Middleware(middleware_class, *args, **kwargs))
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def add_exception_handler(
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self,
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exc_class_or_status_code: int | type[Exception],
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handler: ExceptionHandler,
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) -> None: # pragma: no cover
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self.exception_handlers[exc_class_or_status_code] = handler
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def add_event_handler(
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self,
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event_type: str,
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func: typing.Callable, # type: ignore[type-arg]
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) -> None: # pragma: no cover
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self.router.add_event_handler(event_type, func)
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def add_route(
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self,
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path: str,
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route: typing.Callable[[Request], typing.Awaitable[Response] | Response],
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methods: list[str] | None = None,
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name: str | None = None,
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include_in_schema: bool = True,
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) -> None: # pragma: no cover
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self.router.add_route(
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path, route, methods=methods, name=name, include_in_schema=include_in_schema
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)
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def add_websocket_route(
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self,
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path: str,
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route: typing.Callable[[WebSocket], typing.Awaitable[None]],
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name: str | None = None,
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) -> None: # pragma: no cover
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self.router.add_websocket_route(path, route, name=name)
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def exception_handler(
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self, exc_class_or_status_code: int | type[Exception]
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) -> typing.Callable: # type: ignore[type-arg]
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warnings.warn(
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"The `exception_handler` decorator is deprecated, and will be removed in version 1.0.0. " # noqa: E501
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"Refer to https://www.starlette.io/exceptions/ for the recommended approach.", # noqa: E501
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DeprecationWarning,
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)
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def decorator(func: typing.Callable) -> typing.Callable: # type: ignore[type-arg] # noqa: E501
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self.add_exception_handler(exc_class_or_status_code, func)
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return func
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return decorator
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def route(
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self,
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path: str,
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methods: list[str] | None = None,
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name: str | None = None,
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include_in_schema: bool = True,
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) -> typing.Callable: # type: ignore[type-arg]
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"""
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We no longer document this decorator style API, and its usage is discouraged.
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Instead you should use the following approach:
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>>> routes = [Route(path, endpoint=...), ...]
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>>> app = Starlette(routes=routes)
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"""
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warnings.warn(
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"The `route` decorator is deprecated, and will be removed in version 1.0.0. " # noqa: E501
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"Refer to https://www.starlette.io/routing/ for the recommended approach.", # noqa: E501
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DeprecationWarning,
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)
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def decorator(func: typing.Callable) -> typing.Callable: # type: ignore[type-arg] # noqa: E501
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self.router.add_route(
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path,
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func,
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methods=methods,
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name=name,
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include_in_schema=include_in_schema,
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)
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return func
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return decorator
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def websocket_route(self, path: str, name: str | None = None) -> typing.Callable: # type: ignore[type-arg]
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"""
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We no longer document this decorator style API, and its usage is discouraged.
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Instead you should use the following approach:
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>>> routes = [WebSocketRoute(path, endpoint=...), ...]
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>>> app = Starlette(routes=routes)
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"""
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warnings.warn(
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"The `websocket_route` decorator is deprecated, and will be removed in version 1.0.0. " # noqa: E501
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"Refer to https://www.starlette.io/routing/#websocket-routing for the recommended approach.", # noqa: E501
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DeprecationWarning,
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)
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def decorator(func: typing.Callable) -> typing.Callable: # type: ignore[type-arg] # noqa: E501
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self.router.add_websocket_route(path, func, name=name)
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return func
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return decorator
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def middleware(self, middleware_type: str) -> typing.Callable: # type: ignore[type-arg] # noqa: E501
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"""
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We no longer document this decorator style API, and its usage is discouraged.
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Instead you should use the following approach:
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>>> middleware = [Middleware(...), ...]
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>>> app = Starlette(middleware=middleware)
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"""
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warnings.warn(
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"The `middleware` decorator is deprecated, and will be removed in version 1.0.0. " # noqa: E501
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"Refer to https://www.starlette.io/middleware/#using-middleware for recommended approach.", # noqa: E501
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DeprecationWarning,
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)
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assert (
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middleware_type == "http"
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), 'Currently only middleware("http") is supported.'
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def decorator(func: typing.Callable) -> typing.Callable: # type: ignore[type-arg] # noqa: E501
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self.add_middleware(BaseHTTPMiddleware, dispatch=func)
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return func
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return decorator
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