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-- | Development version to be run inside GHCi.
--
-- start this up with:
--
-- cabal repl --ghc-options="-O0 -fobject-code"
--
-- run with:
--
-- :l DevelMain
-- DevelMain.update
--
-- You will need to add these packages to your .cabal file
-- * foreign-store >= 0.1 (very light-weight)
-- * warp (you already depend on this, it just isn't in your .cabal file)
--
-- If you don't use cabal repl, you will need
-- to add settings to your .ghci file.
--
-- :set -DDEVELOPMENT
--
-- There is more information about using ghci
-- on the wiki: https://github.com/yesodweb/yesod/wiki/ghci
module DevelMain where
import Application (getApplicationDev)
import Control.Exception (finally)
import Control.Concurrent
import Data.IORef
import Foreign.Store
import Network.Wai.Handler.Warp
-- | Start or restart the server.
-- A Store holds onto some data across ghci reloads
update :: IO ()
update = do
mtidStore <- lookupStore tidStoreNum
case mtidStore of
-- no server running
Nothing -> do
done <- storeAction doneStore newEmptyMVar
tid <- start done
_ <- storeAction (Store tidStoreNum) (newIORef tid)
return ()
-- server is already running
Just tidStore ->
-- shut the server down with killThread and wait for the done signal
modifyStoredIORef tidStore $ \tid -> do
killThread tid
withStore doneStore takeMVar >> readStore doneStore >>= start
where
doneStore = Store 0
tidStoreNum = 1
modifyStoredIORef :: Store (IORef a) -> (a -> IO a) -> IO ()
modifyStoredIORef store f = withStore store $ \ref -> do
v <- readIORef ref
f v >>= writeIORef ref
-- | Start the server in a separate thread.
start :: MVar () -- ^ Written to when the thread is killed.
-> IO ThreadId
start done = do
(port,app) <- getApplicationDev
forkIO (finally (runSettings (setPort port defaultSettings) app)
(putMVar done ()))