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module Network.HTTP.Server.Mini (
module Network.HTTP.Server.Mini,
module Network.HTTP.Server.Mini.Types,
) where
import Control.Concurrent
import Control.Concurrent.STM
import Control.Exception
import Control.Monad
import Data.List.NonEmpty qualified as NE
import Network.Socket
import Network.Socket.ByteString
import Network.HTTP.Server.Mini.Parser
import Network.HTTP.Server.Mini.Types
-- | The request handler will run in a forkIO thread.
run :: Settings -> (Request -> IO Response) -> IO ()
run settings handler = do
let hints = defaultHints { addrFlags = [AI_NUMERICHOST, AI_NUMERICSERV, AI_PASSIVE]
, addrSocketType = Stream }
addr <- NE.head <$> getAddrInfo (Just hints) Nothing (Just (show (setPort settings)))
bracket (openSocket addr) close $ \sock -> do
setSocketOption sock ReusePort 1
bind sock (addrAddress addr)
listen sock 64
semaphore <- newTVarIO (setMaxParallelRequests settings)
acceptLoop sock semaphore
where
-- Put the forever _outside_ the mask_ to unmask briefly between iterations
-- (when it's safe because we have nothing ongoing).
acceptLoop sock semaphore = forever $ mask_ $ do
-- Because we're masked, if atomically exits with an async exception, it
-- was while blocking so the transaction failed, so nothing happened, so
-- no cleanup necessary.
atomically $ do
n <- readTVar semaphore
when (n == 0) retry
writeTVar semaphore $! n - 1
let increment = atomically (modifyTVar' semaphore (+1))
(conn, peer) <- accept sock `onException` increment
let cleanup = close conn `finally` increment
onException
(do allowInterrupt -- we're masked but we just blocked (in `accept` in FFI), so let exceptions through
print peer
-- Now either the forkIO succeeds (and the responsibility for
-- closing and incrementing is passed to the thread) or it fails
-- (and we retain both responsibilities).
void $ forkIO $
handleConnection settings conn handler `finally` cleanup)
cleanup
-- | Will not close the connection, instead will just return, expecting the
-- caller to close the connection then.
handleConnection :: Settings -> Socket -> (Request -> IO Response) -> IO ()
handleConnection settings conn handler = do
req <- readRequest (setMaxRequestSize settings) (recv conn)
print req
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