Interrupting a request from within receive in a pure ASGI middleware

[AHarmlessPyro]

Hi all,
I'm trying to make a pure ASGI middleware that needs to analyze the body of a request for certain features (think XSS/CSRF/SQLI kind of stuff), and rejecting the request based on that, along with some response analysis. Now, as far as I understand, it's possible to change the path of a middleware stack if you're in the __call__ function of a middleware (like how the CORS middleware works).

But, if I try to do something like that in the receive function when parsing each individual data chunk, that's not exactly possible. Is there any alternative structure that I should be following, or some pattern that's valid here ? Or is it impossible to stop a request once you've called the next middleware from within the __call__ function.

For reference, here's some reference code for what I'm trying to do:

class ASGIMiddleware:
    def __init__(self,app):
        self.app = app
    
    async def __call__(self,scope,receive,send):
        async def receive_wrapper():
            return await self.receive_fn(scope,send)
        async def send_wrapper(message):
            return await self.send_fn(scope,send,message)
        await self.app(scope,receive_wrapper,send_wrapper)

    async def receive_fn(self,scope,receive,send):
        req = await receive()
        if <CALL_LIBRARY_FOR_DETECTIONS>:
            await PlainTextResponse("Forbidden",403)(scope,receive,send)
            return
        return req

    async def send_fn(self,scope,send,message):
        # Analyze response returned 
        return message
    

As far as I can tell, something like a http.disconnect might be most relevant