On Fri, Feb 4, 2011 at 2:18 PM, Neil Mitchell
Hi,
I've ported Hoogle to WAI/Warp and it's great - I am very happy.
The only feature I lost is the ability to time how long a response takes to generate/send. For my purposes, I'm not even overly bothered whether it's the time taken to generate, or the time taken to send to the clients machine, or something somewhere between these two times. I came up with a couple of ideas:
1) I generate my response with a lazy byte string. I could make the final chunk of the lazy bytestring something impure (with unsafePerformIO) that writes into an MVar when it gets forced. 2) If I knew more about enumerators/iteratees I think it might be possible for each chunk generated to start a time, wait til the chunk is ready, and then stop the timer - giving the exact time to generate all the chunks. Or append two chunks, one at each end, that start/stop the timer.
Does anyone have any better suggestions, or ways of performing the timing?
Depending on how precise you want the answer to be, the easiest solution is a middleware: timeMyResponse app req = do start <- liftIO getCurrentTime res <- app req forceEval res stop <- liftIO getCurrentTime logTime start stop return res The question is what forceEval needs to be. In theory, if you know you're always using the ResponseBuilder constructor (eg, you only ever use responseLBS), this could look like: forceEval (ResponseBuilder b) = return $ L.length $ toLazyByteString b Michael