99 lines
2.9 KiB
Haskell
99 lines
2.9 KiB
Haskell
-- | Running your app inside GHCi.
|
|
--
|
|
-- To start up GHCi for usage with Yesod, first make sure you are in dev mode:
|
|
--
|
|
-- > cabal configure -fdev
|
|
--
|
|
-- Note that @yesod devel@ automatically sets the dev flag.
|
|
-- Now launch the repl:
|
|
--
|
|
-- > cabal repl --ghc-options="-O0 -fobject-code"
|
|
--
|
|
-- To start your app, run:
|
|
--
|
|
-- > :l DevelMain
|
|
-- > DevelMain.update
|
|
--
|
|
-- You can also call @DevelMain.shutdown@ to stop the app
|
|
--
|
|
-- You will need to add the foreign-store package to your .cabal file.
|
|
-- It is very light-weight.
|
|
--
|
|
-- If you don't use cabal repl, you will need
|
|
-- to run the following in GHCi or to add it to
|
|
-- your .ghci file.
|
|
--
|
|
-- :set -DDEVELOPMENT
|
|
--
|
|
-- There is more information about this approach,
|
|
-- on the wiki: https://github.com/yesodweb/yesod/wiki/ghci
|
|
|
|
module DevelMain where
|
|
|
|
import Prelude
|
|
import Application (getApplicationRepl, shutdownApp)
|
|
|
|
import Control.Exception (finally)
|
|
import Control.Monad ((>=>))
|
|
import Control.Concurrent
|
|
import Data.IORef
|
|
import Foreign.Store
|
|
import Network.Wai.Handler.Warp
|
|
import GHC.Word
|
|
|
|
-- | Start or restart the server.
|
|
-- newStore is from foreign-store.
|
|
-- 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 -> restartAppInNewThread tidStore
|
|
where
|
|
doneStore :: Store (MVar ())
|
|
doneStore = Store 0
|
|
|
|
-- shut the server down with killThread and wait for the done signal
|
|
restartAppInNewThread :: Store (IORef ThreadId) -> IO ()
|
|
restartAppInNewThread tidStore = modifyStoredIORef tidStore $ \tid -> do
|
|
killThread tid
|
|
withStore doneStore takeMVar
|
|
readStore doneStore >>= start
|
|
|
|
|
|
-- | Start the server in a separate thread.
|
|
start :: MVar () -- ^ Written to when the thread is killed.
|
|
-> IO ThreadId
|
|
start done = do
|
|
(port, site, app) <- getApplicationRepl
|
|
forkIO (finally (runSettings (setPort port defaultSettings) app)
|
|
-- Note that this implies concurrency
|
|
-- between shutdownApp and the next app that is starting.
|
|
-- Normally this should be fine
|
|
(putMVar done () >> shutdownApp site))
|
|
|
|
-- | kill the server
|
|
shutdown :: IO ()
|
|
shutdown = do
|
|
mtidStore <- lookupStore tidStoreNum
|
|
case mtidStore of
|
|
-- no server running
|
|
Nothing -> putStrLn "no Yesod app running"
|
|
Just tidStore -> do
|
|
withStore tidStore $ readIORef >=> killThread
|
|
putStrLn "Yesod app is shutdown"
|
|
|
|
tidStoreNum :: Word32
|
|
tidStoreNum = 1
|
|
|
|
modifyStoredIORef :: Store (IORef a) -> (a -> IO a) -> IO ()
|
|
modifyStoredIORef store f = withStore store $ \ref -> do
|
|
v <- readIORef ref
|
|
f v >>= writeIORef ref
|