Make transports monitoring easier

[sam-mosleh]

Currently, the only way to use public methods to monitor/instrument requests is to monkey-patch each transport class. By making BaseTransport.handle_request and AsyncBaseTransport.handle_async_request single entry points to all transport subclasses, it would be much easier to monitor them all (by patching only BaseTransport and AsyncBaseTransport), something like the below:

async def _handle_async_request(
    self,
    request: Request,
) -> Response:
    """This method will be overridden by subclasses"""
    raise NotImplementedError("The '_handle_async_request' method must be implemented.")

async def handle_async_request(
    self,
    request: Request,
) -> Response:
    """This method will be the single entrypoint which would make monitoring easier by monkey-patching it"""
    return await self._handle_async_request(request)

I would be happy to try to open a PR for this. Thanks!

[lovelydinosaur]

By making BaseTransport.handle_request and AsyncBaseTransport.handle_async_request single entry points to all transport subclasses

Can you explain to me what you mean here?

[sam-mosleh]

Right now, to monitor every request, we must create sub-classes for each transport:

class MonitoredASGITransport(httpx.ASGITransport):
    async def handle_async_request(
        self,
        request: httpx.Request,
    ) -> httpx.Response:
        start_time = time.time()
        response = await super().handle_async_request(request)
        print("Request took", time.time() - start_time)
        return response

Since it is redundant for each transport class to override handle_async_request, it would be much easier to just monkey-patch BaseTransports:

async def monitored_handle_async_request(
    self,
    request: httpx.Request,
) -> httpx.Response:
    start_time = time.time()
    response = await old_handle(request)
    print("Request took", time.time() - start_time)
    return response


old_handle = httpx.AsyncBaseTransport.handle_async_request
httpx.AsyncBaseTransport.handle_async_request = monitored_handle_async_request

This is achieved by having handle_async_request as the entry point to all subclass's implementations.

[sam-mosleh]

@tomchristie By looking at the example commit I made, which is fully backward-compatible, you can review the entire change.