On Tuesday 24 March 2015 07:01:39 Michael Snoyman wrote:
On Sun, Mar 22, 2015 at 10:01 AM Jos van den Oever
wrote:
On Sunday 08 March 2015 07:28:30 you wrote:
I've updated that Gist to be compatible with WAI 3.0. The basic changes I made were:
1. Change the way Warp settings are applied (no longer use record syntax, but explicit set* functions). 2. conduit is no longer the standard streaming interface for WAI, so imported Network.Wai.Conduit and used helper functions from there. 3. The specific question you asked about: the semantics for how to do resource allocation in an application have changed. There were some holes in the previous approach that allowed async exceptions to leak in at the wrong time. Instead, WAI 3.0 uses a similar interface to most resource allocation functions in Haskell (like bracket or withFile). Specifically,
this looks like: HCl.withResponse req2 man $ \res -> do
let body = mapOutput (Chunk . fromByteString) $
HCC.bodyReaderSource $ HCl.responseBody res
headers = filter safeResHeader $ HCl.responseHeaders res
respond $ responseSource (HCl.responseStatus res) headers body
I'd like my proxy to be a caching proxy so each request shoule be saved to a file. I've tried adding an additional sink, (sinkFile) or conduit (conduitFie) to the HCC.bodyReaderSource, but cannot it right. What would be a good way to do this?
What have you tried so far?
This is the code I have so far. I've annotated with a types. This code gives a compile error because of the line 'source2 = bodySource C.=$= fileSaver'. The MonadResource is not arising from the use in fileSaver. Somehow, I've to get runResourceT in there. === HCl.withResponse req2 man $ \res -> do --saver <- CB.conduitFile "/tmp/out" let path = "/tmp/out" :: FilePath fileSaver :: MonadResource m => C.Conduit S8.ByteString m S8.ByteString fileSaver = CB.conduitFile path bodyReader :: HCl.BodyReader bodyReader = HCl.responseBody res bodySource :: MonadIO m => C.ConduitM () S8.ByteString m () bodySource = HCC.bodyReaderSource bodyReader source2 = bodySource C.=$= fileSaver chunk :: S8.ByteString -> C.Flush Builder chunk = C.Chunk . fromByteString body :: C.ConduitM () (C.Flush Builder) IO() body = C.mapOutput chunk source2 headers = filter removeEncodingHeaders $ HCl.responseHeaders res time <- getPOSIXTime runSqlPool (insert_ $ Response (round time) reqid Nothing) pool respond $ WC.responseSource (HCl.responseStatus res) headers body === Cheers, Jos