wizard-wipeout/src-server/Server/Communication.hs
2023-12-11 09:49:24 +01:00

177 lines
4.9 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
module Server.Communication where
import Control.Concurrent
import qualified Control.Concurrent.STM as STM
import Control.Monad
import Control.Monad.IO.Class
import Control.Monad.RWS.Strict
import qualified Data.Aeson as A
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy.Char8 as B8
import Data.List
import Data.Maybe
import Data.UUID.V4
import qualified Data.Vector.Storable as VS
import Foreign hiding (void)
import Network.Socket as Net
import System.Posix.Signals
-- internal imports
import Library.Types
import Server.Types
import Server.Util
-- | Function which determines whether the given filePath is a supported socket path and
-- subsequently creates a socket in said location.
bindSocket
:: FilePath -- ^ File Path for socket to be created (e.g.: "/tmp/wizard.sock")
-> IO Socket -- ^ resulting Socket
bindSocket path = do
let sockAddr = SockAddrUnix path
unless (isSupportedSockAddr sockAddr)
(error $ "invalid socket path " <> path)
-- aremoveIfExists path
sock <- socket AF_UNIX Stream defaultProtocol
bind sock sockAddr
Net.listen sock 5
pure sock
-- | Function that installs a handler on SIGINT to terminate game
terminateGameOnSigint
:: Game ()
terminateGameOnSigint = do
sock <- asks rcMainSocket
clients <- liftIO . STM.atomically . STM.readTMVar =<< gets scClientSockets
serverState <- gets scServerState
void $ liftIO $ installHandler
keyboardSignal
(CatchOnce $ do
void $ STM.atomically $ STM.swapTMVar serverState (ServerState False True)
disconnectClients clients
threadDelay (10 ^ 6)
(SockAddrUnix path) <- getSocketName sock
close sock
removeIfExists path
-- Raise SIGINT again so it does not get blocked
raiseSignal keyboardSignal
)
Nothing
where
disconnectClients = mapM_
(\(_, clientSocket) -> do
close clientSocket
)
-- | Process incoming connection requests
processRequests :: Game ()
processRequests = do
mainSocket <- asks rcMainSocket
socketList <- gets scClientSockets
void $ liftIO $ forkIO $ acceptConnection mainSocket socketList
where
acceptConnection mainSocket socketList = do
putStrLn "accepting new connections…"
(clientSock, _) <- accept mainSocket
liftIO $ STM.atomically $ do
list <- STM.takeTMVar socketList
STM.putTMVar socketList ((Nothing, clientSock) : list)
putStrLn "accepted new connection"
acceptConnection mainSocket socketList
-- | Sends a specified message through given socket to the client
sendMessage
:: ServerMessage
-> Socket
-> IO ()
sendMessage msg sock = do
let msgJson = A.encode msg
msgVector = VS.fromList $ B.unpack $ B.toStrict msgJson
VS.unsafeWith
msgVector
(\ptr -> void $ sendBuf sock ptr (VS.length msgVector))
-- | process incoming messages from clients
processMessages :: Game ()
processMessages = do
clientsVar <- gets scClientSockets
clients <- liftIO $ STM.atomically $ STM.readTMVar clientsVar
mapM_
(\(uuid, clientSocket) -> do
receiveMessage clientSocket
handleMessage
)
clients
-- | receive a 'ClientMessage'
receiveMessage
:: Socket
-> Game ()
receiveMessage sock = do
let maxBufferLength = 4096
mmsg <- liftIO $ do
ptr <- mallocArray maxBufferLength
bufferLength <- recvBuf sock ptr maxBufferLength
msg <- B.pack <$> peekArray bufferLength ptr
let mJsonMsg = A.decode' $ B8.fromStrict msg :: Maybe ClientMessage
free ptr
if bufferLength > 0
then
pure mJsonMsg
else
pure Nothing
maybe
(pure ())
(\msg -> do
queue <- gets scMessageQueue
liftIO $ STM.atomically $ STM.writeTQueue queue msg
)
mmsg
-- | function for translating 'ClientMessage's into server actions
handleMessage
:: Game ()
handleMessage = do
queue <- gets scMessageQueue
msgs <- liftIO $ STM.atomically $ STM.flushTQueue queue
clientList <- gets scClientSockets
clients <- liftIO $ STM.atomically $ STM.readTMVar clientList
mapM_
(\msg -> liftIO $ do
putStrLn "Handling following:"
print msg
case msg of
IdRequest -> do
clientId <- nextRandom
let clientIdx = findIndex (\a -> fst a == Nothing) clients
let clientSock = snd $ clients !! fromJust clientIdx
sendMessage (AcceptClient clientId) clientSock
putStrLn $ "Accepted Client with UUID " <> show clientId
let newClients = map
(\old@(muuid, oldClientSock) ->
if oldClientSock == clientSock && muuid == Nothing
then
(Just clientId, clientSock)
else
old
)
clients
void $ liftIO $ STM.atomically $ STM.swapTMVar clientList newClients
_ -> pure ()
)
msgs