QHP: send multipart data

mds.cabal

@@ -36,6 +36,7 @@ library
                      , attoparsec
                      , binary
                      , binary-ieee754
+                     , conduit
   default-language:    Haskell2010
   other-modules:       ATrade.MDS.Protocol
   default-extensions:  OverloadedStrings

src/ATrade/MDS/Database.hs

@@ -6,6 +6,7 @@ module ATrade.MDS.Database (
   initDatabase,
   closeDatabase,
   getData,
+  getDataConduit,
   putData,
   TimeInterval(..),
   Timeframe(..),
@@ -16,6 +17,9 @@ module ATrade.MDS.Database (
 
 import           ATrade.Types
 import           Control.Monad
+import           Control.Monad.IO.Class
+import           Control.Monad.Loops
+import           Data.Conduit
 import           Data.Maybe
 import qualified Data.Text              as T
 import           Data.Time.Clock
@@ -78,6 +82,25 @@ getData db tickerId interval@(TimeInterval start end) (Timeframe tfSec) = do
     }
     barFromResult _ _ = Nothing
 
+getDataConduit :: (MonadIO m) => MdsHandle -> TickerId -> TimeInterval -> Timeframe -> ConduitT () Bar m ()
+getDataConduit db tickerId (TimeInterval start end) (Timeframe tfSec) = do
+  stmt <- liftIO $ prepare db "SELECT timestamp, timeframe, open, high, low, close, volume FROM bars WHERE ticker == ? AND timeframe == ? AND timestamp >= ? AND timestamp <= ? ORDER BY timestamp ASC;"
+  _ <- liftIO $ execute stmt [(toSql. T.unpack) tickerId, toSql tfSec, (toSql . utcTimeToPOSIXSeconds) start, (toSql . utcTimeToPOSIXSeconds) end]
+  whileJust_ (liftIO $ fetchRow stmt) $ \row -> case barFromResult tickerId row of
+    Just bar -> yield bar
+    Nothing  -> return ()
+  where
+    barFromResult ticker [ts, _, open, high, low, close, vol] = Just Bar {
+      barSecurity = ticker,
+      barTimestamp = fromSql ts,
+      barOpen = fromDouble $ fromSql open,
+      barHigh = fromDouble $ fromSql high,
+      barLow = fromDouble $ fromSql low,
+      barClose = fromDouble $ fromSql close,
+      barVolume = fromSql vol
+    }
+    barFromResult _ _ = Nothing
+
 putData :: MdsHandle -> TickerId -> TimeInterval -> Timeframe -> V.Vector Bar -> IO ()
 putData db tickerId (TimeInterval start end) tf@(Timeframe tfSec) bars = do
   withTransaction db $ \db' -> do

src/ATrade/MDS/HistoryServer.hs

@@ -11,11 +11,14 @@ import           ATrade.MDS.Protocol
 import           ATrade.Types
 import           Control.Concurrent
 import           Control.Monad
+import           Control.Monad.IO.Class
 import           Data.Aeson
 import           Data.Binary.Get
 import           Data.Binary.Put
 import qualified Data.ByteString          as B
 import qualified Data.ByteString.Lazy     as BL
+import           Data.Conduit             as C
+import           Data.Conduit.Combinators
 import           Data.List.NonEmpty
 import qualified Data.Text                as T
 import           Data.Time.Clock.POSIX
@@ -56,9 +59,20 @@ serveQHP db sock = forever $ do
     handleCmd peerId cmd = case cmd of
       rq -> do
         debugM "QHP" $ "Incoming command: " ++ show cmd
-        qdata <- getData db (rqTicker rq) (TimeInterval (rqStartTime rq) (rqEndTime rq)) (Timeframe (periodSeconds $ rqPeriod rq))
+        let dataC = getDataConduit db (rqTicker rq) (TimeInterval (rqStartTime rq) (rqEndTime rq)) (Timeframe (periodSeconds $ rqPeriod rq))
-        let bytes = serializeBars $ V.concat $ fmap snd qdata
+        runConduit $ dataC .| (conduitVector chunkSize) .| (sendChunks peerId)
-        sendMulti sock $ peerId :| [B.empty, "OK", BL.toStrict bytes]
+        --qdata <- getData db (rqTicker rq) (TimeInterval (rqStartTime rq) (rqEndTime rq)) (Timeframe (periodSeconds $ rqPeriod rq))
+        --let bytes = serializeBars $ V.concat $ fmap snd qdata
+        --sendMulti sock $ peerId :| [B.empty, "OK", BL.toStrict bytes]
+    sendChunks :: (MonadIO m) => B.ByteString -> ConduitT (V.Vector Bar) Void m ()
+    sendChunks peerId = do
+      liftIO $ send sock [SendMore] peerId
+      liftIO $ send sock [SendMore] B.empty
+      liftIO $ send sock [SendMore] "OK"
+      awaitForever $ \vBars -> liftIO $ do
+        debugM "QHP" $ "Sending chunk: " ++ show (V.length vBars) ++ " bars"
+        send sock [SendMore] $ BL.toStrict $ serializeBars vBars
+      liftIO $ send sock [] B.empty
     serializeBars :: V.Vector Bar -> BL.ByteString
     serializeBars bars = runPut $ V.forM_ bars serializeBar'
     serializeBar' bar = do
@@ -69,6 +83,8 @@ serveQHP db sock = forever $ do
       putDoublele (toDouble . barClose $ bar)
       putWord64le (fromInteger . barVolume $ bar)
 
+    chunkSize = 4096
+
 serveHAP :: (Sender a, Receiver a) => MdsHandle -> Socket a -> IO ()
 serveHAP db sock = forever $ do
   rq <- receiveMulti sock