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{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE ExplicitNamespaces #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedLists #-}
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TypeApplications #-}
-- Implementation of the API. This module is the main point of the program.
module Server (application) where
import Control.Monad (forever, void, when)
import Control.Monad.Extra (maybeM, whenM)
import Control.Monad.IO.Class (MonadIO (liftIO))
import Control.Monad.Logger (logWarnN)
import Control.Monad.Reader (forM)
import Control.Monad.Trans (lift)
import qualified Data.Aeson as A
import qualified Data.ByteString.Char8 as C8
import Data.Coerce (coerce)
import Data.Functor ((<&>))
import qualified Data.Map as M
import Data.Pool (Pool)
import Data.Proxy (Proxy (Proxy))
import Data.Swagger (toSchema)
import Data.Text (Text)
import Data.Time (NominalDiffTime,
UTCTime (utctDay), addUTCTime,
diffUTCTime, getCurrentTime,
nominalDay)
import qualified Data.Vector as V
import Database.Persist
import Database.Persist.Postgresql (SqlBackend, runMigration)
import Fmt ((+|), (|+))
import qualified Network.WebSockets as WS
import Servant (Application, err401, err404,
serve, throwError)
import Servant.API (NoContent (..), (:<|>) (..))
import Servant.Server (Handler, hoistServer)
import Servant.Swagger (toSwagger)
import API
import GTFS
import Persist
import Server.ControlRoom
import Server.GTFS_RT (gtfsRealtimeServer)
import Server.Util (Service, ServiceM, runService)
application :: GTFS -> Pool SqlBackend -> IO Application
application gtfs dbpool = do
doMigration dbpool
pure $ serve (Proxy @CompleteAPI) $ hoistServer (Proxy @CompleteAPI) runService $ server gtfs dbpool
-- databaseMigration :: ConnectionString -> IO ()
doMigration pool = runSql pool $
-- TODO: before that, check if the uuid module is enabled
-- in sql: check if SELECT * FROM pg_extension WHERE extname = 'uuid-ossp';
-- returns an empty list
runMigration migrateAll
server :: GTFS -> Pool SqlBackend -> Service CompleteAPI
server gtfs@GTFS{..} dbpool = handleDebugAPI :<|> (handleStations :<|> handleTimetable :<|> handleTrip
:<|> handleRegister :<|> handleTripPing :<|> handleWS :<|> handleDebugState :<|>
gtfsRealtimeServer gtfs dbpool
:<|> adminServer gtfs dbpool)
:<|> controlRoomServer gtfs dbpool
where handleStations = pure stations
handleTimetable station maybeDay = do
-- TODO: resolve "overlay" trips (perhaps just additional CalendarDates?)
day <- liftIO $ maybeM (getCurrentTime <&> utctDay) pure (pure maybeDay)
pure
-- don't send stations ending at this station
. M.filter ((==) station . stationId . stopStation . V.last . tripStops)
$ tripsOnDay gtfs day
handleTrip trip = case M.lookup trip trips of
Just res -> pure res
Nothing -> throwError err404
handleRegister tripID = do
-- TODO registration may carry extra information!
expires <- liftIO $ getCurrentTime <&> addUTCTime validityPeriod
RunningTripKey token <- runSql dbpool $ insert (RunningTrip expires False tripID Nothing)
pure token
handleTripPing ping = do
lift $ checkTokenValid dbpool (coerce $ tripPingToken ping)
-- TODO: are these always inserted in order?
runSql dbpool $ insert ping
pure NoContent
handleWS conn = do
-- TODO test this!!
liftIO $ WS.forkPingThread conn 30
forever $ do
msg <- liftIO $ WS.receiveData conn
case A.eitherDecode msg of
Left err -> do
logWarnN ("stray websocket message: "+|show msg|+" (could not decode: "+|err|+")")
liftIO $ WS.sendClose conn (C8.pack err)
Right ping -> do
lift $ checkTokenValid dbpool (coerce $ tripPingToken ping)
void $ runSql dbpool $ insert ping
handleDebugState = do
now <- liftIO getCurrentTime
runSql dbpool $ do
running <- selectList [RunningTripBlocked ==. False, RunningTripExpires >=. now] []
pairs <- forM running $ \(Entity token@(RunningTripKey uuid) _) -> do
entities <- selectList [TripPingToken ==. token] []
pure (uuid, fmap entityVal entities)
pure (M.fromList pairs)
handleDebugAPI = pure $ toSwagger (Proxy @API)
adminServer :: GTFS -> Pool SqlBackend -> Service AdminAPI
adminServer gtfs dbpool =
addAnnounce :<|> delAnnounce :<|> modTripDate Added Cancelled
:<|> modTripDate Cancelled Added :<|> extraTrip
where addAnnounce ann@Announcement{..} = runSql dbpool $ do
AnnouncementKey uuid <- insert ann
pure uuid
delAnnounce uuid = runSql dbpool $ do
delete (AnnouncementKey uuid)
pure NoContent
modTripDate one two tripId day = runSql dbpool $ do
getBy (TripAndDay tripId day) >>= \case
Just (Entity key (ScheduleAmendment _ _ status)) -> do
when (status == two) $ delete key
pure NoContent
Nothing -> do
insert (ScheduleAmendment tripId day one)
pure NoContent
extraTrip = error "unimplemented!"
-- TODO: proper debug logging for expired tokens
checkTokenValid :: Pool SqlBackend -> Token -> Handler ()
checkTokenValid dbpool token = do
trip <- try $ runSql dbpool $ get (coerce token)
when (runningTripBlocked trip)
$ throwError err401
whenM (hasExpired (runningTripExpires trip))
$ throwError err401
where try m = m >>= \case
Just a -> pure a
Nothing -> throwError err404
hasExpired :: MonadIO m => UTCTime -> m Bool
hasExpired limit = do
now <- liftIO getCurrentTime
pure (now > limit)
validityPeriod :: NominalDiffTime
validityPeriod = nominalDay
|
