yesod/yesod-core/Yesod/Main.hs
2011-09-11 00:35:34 -04:00

75 lines
2.3 KiB
Haskell

{-# LANGUAGE DeriveDataTypeable #-}
module Yesod.Main
( defaultMain
, fromArgs
, fromArgsWith
) where
import Yesod.Logger (Logger, makeLogger)
import Yesod.Settings (AppEnvironment(..), AppConfig(..), loadConfig)
import Network.Wai (Application)
import Network.Wai.Handler.Warp (run)
import System.Console.CmdArgs hiding (args)
import Data.Char (toUpper, toLower)
data ArgConfig = ArgConfig
{ environment :: String
, port :: Int
} deriving (Show, Data, Typeable)
-- | Load an @'AppConfig'@ using the provided function, then start your
-- app via Warp on the configured port.
--
-- > -- main.hs
-- > import Application (withMySite)
-- > import Yesod.Main (defaultMain, fromArgs)
-- >
-- > main :: IO ()
-- > main = defaultMain fromArgs withMySite
--
defaultMain :: IO AppConfig -> (AppConfig -> Logger -> (Application -> IO ()) -> IO ()) -> IO ()
defaultMain load withSite = do
config <- load
logger <- makeLogger
withSite config logger $ run (appPort config)
-- | Call the @'Yesod.Settings.loadConfig'@ function for the environment
-- passed on the commandline (or the default, \"development\") and
-- override the port if passed.
fromArgs :: IO AppConfig
fromArgs = fromArgsWith loadConfig
-- | Same, but allows one to provide their own custom @'loadConfig'@
fromArgsWith :: (AppEnvironment -> IO AppConfig) -> IO AppConfig
fromArgsWith load = do
args <- cmdArgs argConfig
let env = read
$ capitalize
$ if environment args /= ""
then environment args
else "development"
config <- load env
return $ if port args /= 0
then config { appPort = port args }
else config
where
argConfig :: ArgConfig
argConfig = ArgConfig
{ environment = def
&= help ("application environment, one of: " ++ (foldl1 (\a b -> a ++ ", " ++ b) environments))
&= typ "ENVIRONMENT"
, port = def
&= help "the port to listen on"
&= typ "PORT"
}
environments :: [String]
environments = map ((map toLower) . show) ([minBound..maxBound] :: [AppEnvironment])
capitalize [] = []
capitalize (x:xs) = toUpper x : map toLower xs