-response :: Monad m => ConduitParser FromServerMessage m FromServerMessage
-response = satisfy isServerResponse
+anyResponse :: Monad m => ConduitParser FromServerMessage m FromServerMessage
+anyResponse = satisfy isServerResponse
+
+response :: forall m a. (Monad m, FromJSON a) => ConduitParser FromServerMessage m (ResponseMessage a)
+response = do
+ let parser = decode . encodeMsg :: FromServerMessage -> Maybe (ResponseMessage a)
+ x <- satisfy (isJust . parser)
+ return $ decodeMsg $ encodeMsg x
+
+-- | A version of encode that encodes FromServerMessages as if they
+-- weren't wrapped.
+encodeMsg :: FromServerMessage -> B.ByteString
+encodeMsg = encode . genericToJSON (defaultOptions { sumEncoding = UntaggedValue })
+
+decodeMsg :: FromJSON a => B.ByteString -> a
+decodeMsg x = fromMaybe (error $ "Unexpected message type\nGot:\n " ++ show x)
+ (decode x)