Re: [web-devel] HTTP Status with Streaming Request Bodies

29 Feb 2016


      Looking through the code and experimenting, using the 'Expect:
100-continue' header resulted in the desired behavior - having the response
headers checked before the request body was streamed.

Mark

On Sun, Feb 28, 2016 at 2:20 PM, Mark Fine  wrote:
...
I'm running into a problem handling requests with streaming request bodies
that fail - using http-client, the failure takes a long time (potentially
never) to propagate. Simple code (runnable project here
https://github.com/mfine/streamy):
{-# LANGUAGE OverloadedStrings #-}
import Control.Monad
import Data.Conduit.Combinators
import Network.HTTP.Conduit
import System.Environment
a :: IO ()
a = do
  manager <- newManager tlsManagerSettings
  request <- parseUrl "http://httpbin.org/status/409"
  void $ httpLbs request manager
b :: IO ()
b = do
  manager <- newManager tlsManagerSettings
  request <- parseUrl "http://httpbin.org/status/409"
  void $ flip httpLbs manager request
    { requestBody = requestBodySourceChunked $ repeatM $ return "a"
    }
Running "a" above works as expected (propagating the error immediately).
Running "b" has variable results, mostly never propagating the error.
Looking at the wire, I can see that the 409 status comes back, but the
exception does not propagate.
Is there something I can do here to get quicker failure? Thanks!
Mark