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{-# Language QuasiQuotes #-}
module Fig.Bus.Client (Commands(..), busClient) where
import Fig.Prelude
import System.Exit (exitFailure)
import qualified Control.Concurrent as Conc
import Data.ByteString (hPut, hGetLine)
import Fig.Utils.Net
import Fig.Utils.SExpr
data Commands m = Commands
{ ping :: m ()
, subscribe :: SExpr -> m ()
, publish :: SExpr -> [SExpr] -> m ()
}
newtype FigBusClientException = FigBusClientException Text
deriving (Show, Eq, Ord)
instance Exception FigBusClientException
busClient :: forall m.
(MonadIO m, MonadThrow m, MonadMask m) =>
(Text, Text) ->
(Commands IO -> IO ()) ->
(Commands IO -> SExpr -> IO ()) ->
IO () ->
m ()
busClient loc@(host, port) onConn onData onQuit = catchFailure . client loc $ pure \h ->
let
sendSexpr x = liftIO . hPut h . encodeUtf8 $ pretty x <> "\n"
cmds = Commands
{ ping = sendSexpr [sexp|(ping)|]
, subscribe = \ev -> sendSexpr [sexp|(sub ,ev)|]
, publish = \ev d -> sendSexpr [sexp|(pub ,ev ,@d)|]
}
in
( do
liftIO . void . Conc.forkIO $ onConn cmds
forever do
line <- throwLeft id . decodeUtf8' =<< liftIO (hGetLine h)
case parseSExpr line of
Nothing -> throwM . FigBusClientException $ "Server sent malformed s-expression: " <> line
Just x -> liftIO $ onData cmds x
, liftIO onQuit
)
where
catchFailure body = catch body \(e :: IOException) -> do
log $ "Failed to connect to bus at " <> host <> ":" <> port <> ": " <> tshow e
liftIO $ exitFailure
_testClient :: IO ()
_testClient = busClient ("localhost", "32050")
(\cmds -> do
cmds.subscribe [sexp|foo|]
forever do
Conc.threadDelay 1000000
cmds.publish [sexp|bar|] [[sexp|42|]]
)
(\_cmds d -> putStrLn $ "Received: " <> pretty d)
(pure ())
|
