forest/src/Forest/Server.hs

61 lines
2.2 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
module Forest.Server
( withThread
, serverApp
) where
import Control.Concurrent.Chan
import Control.Monad
import qualified Network.WebSockets as WS
import Forest.Api
import Forest.Node
import Forest.TreeModule
import Forest.Util
{- Thread that sends updates to the client -}
sendUpdatesThread :: WS.Connection -> Chan Node -> Node -> IO ()
sendUpdatesThread conn nodeChan _ = do
newNode <- readChan nodeChan
-- TODO Don't send the whole node every time
putStrLn $ "Sending full node update with " ++ show newNode
sendPacket conn $ ServerUpdate (Path []) newNode
sendUpdatesThread conn nodeChan newNode
{- Main server application that receives and processes client packets -}
receivePackets :: TreeModule a => WS.Connection -> a -> IO ()
receivePackets conn treeModule = forever $ do
packet <- receivePacket conn
case packet of
ClientEdit path text -> do
putStrLn $ "Editing " ++ show path ++ " to " ++ show text
edit treeModule path text
ClientDelete path -> do
putStrLn $ "Deleting " ++ show path
delete treeModule path
ClientReply path text -> do
putStrLn $ "Replying to " ++ show path ++ " with " ++ show text
reply treeModule path text
ClientAct path -> do
putStrLn $ "Acting upon " ++ show path
act treeModule path
ClientHello _ -> closeWithErrorMessage conn "Invalid packet: Hello can only be sent once"
serverApp :: TreeModule a => Int -> ModuleConstructor a -> WS.ServerApp
serverApp pingDelay constructor pendingConnection = do
conn <- WS.acceptRequest pendingConnection
chan <- newChan
WS.withPingThread conn pingDelay (pure ()) $ do
firstPacket <- receivePacket conn
case firstPacket of
ClientHello _ -> do
putStrLn $ "Sending hello reply with " ++ show initialNode
sendPacket conn $ ServerHello [] initialNode
withThread (sendUpdatesThread conn chan initialNode) $
constructor (writeChan chan) $ receivePackets conn
_ -> closeWithErrorMessage conn "Invalid packet: Expected a hello packet"
where
initialNode = emptyNode "Loading ..." False False False False