68 lines
2.2 KiB
Python
68 lines
2.2 KiB
Python
import asyncio
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import typing
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from starlette.requests import Request
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from starlette.responses import Response, StreamingResponse
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from starlette.types import ASGIApp, Receive, Scope, Send
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RequestResponseEndpoint = typing.Callable[[Request], typing.Awaitable[Response]]
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DispatchFunction = typing.Callable[
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[Request, RequestResponseEndpoint], typing.Awaitable[Response]
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]
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class BaseHTTPMiddleware:
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def __init__(self, app: ASGIApp, dispatch: DispatchFunction = None) -> None:
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self.app = app
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self.dispatch_func = self.dispatch if dispatch is None else dispatch
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async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
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if scope["type"] != "http":
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await self.app(scope, receive, send)
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return
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request = Request(scope, receive=receive)
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response = await self.dispatch_func(request, self.call_next)
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await response(scope, receive, send)
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async def call_next(self, request: Request) -> Response:
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loop = asyncio.get_event_loop()
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queue = asyncio.Queue() # type: asyncio.Queue
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scope = request.scope
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receive = request.receive
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send = queue.put
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async def coro() -> None:
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try:
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await self.app(scope, receive, send)
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finally:
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await queue.put(None)
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task = loop.create_task(coro())
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message = await queue.get()
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if message is None:
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task.result()
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raise RuntimeError("No response returned.")
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assert message["type"] == "http.response.start"
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async def body_stream() -> typing.AsyncGenerator[bytes, None]:
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while True:
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message = await queue.get()
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if message is None:
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break
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assert message["type"] == "http.response.body"
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yield message.get("body", b"")
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task.result()
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response = StreamingResponse(
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status_code=message["status"], content=body_stream()
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)
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response.raw_headers = message["headers"]
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return response
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async def dispatch(
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self, request: Request, call_next: RequestResponseEndpoint
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) -> Response:
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raise NotImplementedError() # pragma: no cover
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