{-# LANGUAGE ScopedTypeVariables #-}
module Happstack.Server.Helpers
( smartserver, exactdir, smartserver',getData',vhosts,vhost
) where
import qualified Control.Exception as E
import Data.IORef
import Happstack.Server
import Happstack.State
import System.Environment
import Control.Concurrent
import System.Time
import Control.Monad
import Debug.Trace.Helpers
import Data.Maybe (fromMaybe)
import qualified Data.ByteString.Char8 as B
import System.Exit
-- run the happs server on some port
-- include cookie fix, various other enhancements that make things simpler
smartserver' :: (Methods st, Component st, ToMessage b, Monad m, Functor m) =>
(m (Maybe (Either Response a, FilterFun Response)) ->
IO (Maybe (Either Response b, FilterFun Response))) ->
Conf -> ServerPartT m a -> Proxy st -> IO ()
smartserver' f conf handler stateProxy = do
putStrLn . ( "starting happs server" ++ ) =<< time
control <- startSystemState stateProxy -- start the HAppS state system
putStrLn . ( "happs state started" ++ ) =<< time
-- if the web server throws an error within 3 seconds, exit app gracefully (is there a better way to handle this?)
(webserverTid,result) <- catchStartupErrorInForkIO (simpleHTTP' f conf handler) 3
case result of
Left e -> do putStrLn $ "smartserver' couldn't start http server: " ++ (show e)
stateShutdown control
exitWith $ ExitFailure 0
_ -> putStrLn . ( ( "simpleHttp started on port " ++ (show . port $ conf) ++ "\n" ++
"shut down with ctrl-c" ) ++) =<< time
waitForTermination
killThread webserverTid
stateShutdown control
time = return . ("\ntime: " ++ ) . show =<< getClockTime
stateShutdown control = do
putStrLn . ( "creating checkpoint: " ++ ) =<< time
createCheckpoint control
putStrLn . ( "shutting down system: " ++ ) =<< time
shutdownSystem control
putStrLn . ( "exiting: " ++ ) =<< time
smartserver :: (Methods st, Component st, ToMessage a) =>
Conf -> ServerPartT IO a -> Proxy st -> IO ()
smartserver = smartserver' id
exactdir :: (Monad m) => String -> ServerPartT m a -> ServerPartT m a
exactdir staticPath = spsIf (\rq -> rqURL rq == staticPath)
spsIf :: (Monad m) => (Request -> Bool) -> ServerPartT m a -> ServerPartT m a
spsIf p sps = do
rq <- askRq
if p rq
then sps
else mzero
getData' :: (ServerMonad m, FromData a, MonadPlus m) => m a
getData' = getData >>= maybe mzero return
-- | multiple vhosts to a server, eg
-- | vhosts [("mysite.com",80),("www.mysite.com",80)] mySiteController
vhosts hosts sp = msum . map (\h -> vhost h sp) $ hosts
{- | vhost doms h = msum . map (\d -> site d h) doms
similar to apache vhost. given (domain,port) and a main request handler, handle requests if it's the specified domain and port
vhost ("mysite.com",80) mySiteController
-}
vhost :: (String,Int) -> ServerPartT IO Response -> ServerPartT IO Response
vhost vh@(domain, port) sp = do
(p :: Int) <- liftM ( snd . rqPeer ) askRq
(d :: String) <- (B.unpack . fromMaybe (error "Happstack.Helpers.Server.vhost, no host header")) `liftM` getHeaderM "host"
guardRq $ \rq -> (d,p) == vh
sp
{-| If a forked IO action throws an exception within a certain amount of time, return the exception along with the threadId.
wait time needs to be long enough for the exception to arise, so when in doubt, err on the side of longer wait time
-}
catchStartupErrorInForkIO :: IO () -> Int -> IO (ThreadId, Either E.SomeException ())
catchStartupErrorInForkIO ioAction waitSeconds = do
eIOref <- newIORef $ Right ()
tid <- forkIO $ ioAction `E.catch` (\e -> writeIORef eIOref (Left e))
threadDelay $ waitSeconds * (10^6)
new <- readIORef eIOref
return (tid,new)