How to update request parameters in FastAPI

Question

I am using FastAPI, I want to define a Middleware in which I can intercept the encrypted parameters passed by the front-end and decrypt them, and replace the original parameters with the decrypted ones, what should I do? I have tried

body = await request.body()
request._body = body

Also I have tried

async def set_body(request: Request, body: bytes):
    async def receive() -> Message:
        return {"type": "http.request", "body": body}

    request._receive = receive

async def get_body(request: Request) -> bytes:
    body = await request.body()
    set_body(request, body)
    return body

But still no solution, can anyone give a solution to the problem, thanks a lot!

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class GzipRequest(Request):
    async def body(self) -> bytes:
        # if not hasattr(self, "_body"):
        body = await super().body()
        # if "gzip" in self.headers.getlist("Content-Encoding"):
        #     body = gzip.decompress(body)
        self._body = body
        return self._body

class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler
app.router.route_class = GzipRoute

I also tested this method, but it still didn't work！

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I have solved this problem by app.router.route_class = GzipRoute, main tip: when defining a route in another class, you also need to make a route class, for example:

router = APIRouter(route_class=GzipRoute)