gistfile1.hs

main = do
	config <- readDbConfig
	let runAction = withConnection config
	S.scotty 3000 $ do
		S.get "/" $ do
			res <- liftIO . runAction $ getOpportunity
			S.json $ Opportunities res

		S.post "/opportunities/" $ do
			requestBody <- S.body
			res <- liftIO . runAction $ createOpportunity (decode requestBody :: Maybe OpportunityContract)
			S.json $ case res of
				Nothing -> Opportunities []
				Just x -> Opportunities [x]

type SOAction a = Connection -> IO a

getOpportunity :: SOAction [M.Opportunity]
getOpportunity conn = CE.run conn program
	where program = CE.getOpportunity 1

createOpportunity :: Maybe OpportunityContract -> SOAction (Maybe M.Opportunity)
createOpportunity (Just (OpportunityContract c)) conn = 
	let accOpportunity = M.create (Just (title c)) (Just (description c)) (maxAttendees c)
	in case (accOpportunity ^? _Success) of
		Nothing -> return Nothing
		(Just c) -> do
			CE.run conn program
				where program = CE.createOpportunity c
createOpportunity Nothing conn = return Nothing

withConnection :: DbConfig -> SOAction a -> IO a
withConnection config f = do
	conn <- connectPostgreSQL $ getConnectionString config
	f conn