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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, unless, void, when)
import Control.Monad.Extra (maybeM, unlessM, 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,
ServerError (errBody), 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,
sendErrorMsg)
import Yesod (toWaiAppPlain)
import Extrapolation (Extrapolator (guessAnchor),
LinearExtrapolator)
import System.IO.Unsafe
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 :<|> handleTrainPing :<|> handleWS
:<|> handleDebugState :<|> handleDebugTrain :<|> handleDebugRegister
:<|> gtfsRealtimeServer gtfs dbpool)
:<|> pure (unsafePerformIO (toWaiAppPlain (ControlRoom 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 RegisterJson{..} = do
today <- liftIO getCurrentTime <&> utctDay
when (not $ runsOnDay gtfs tripID today)
$ sendErrorMsg "this trip does not run today."
expires <- liftIO $ getCurrentTime <&> addUTCTime validityPeriod
RunningKey token <- runSql dbpool $ insert (Running expires False tripID today Nothing registerAgent)
pure token
handleDebugRegister tripID day = do
expires <- liftIO $ getCurrentTime <&> addUTCTime validityPeriod
RunningKey token <- runSql dbpool $ insert (Running expires False tripID day Nothing "debug key")
pure token
handleTrainPing ping = do
running@Running{..} <- lift $ checkTokenValid dbpool (coerce $ trainPingToken ping)
let anchor = guessAnchor @LinearExtrapolator gtfs running ping
-- TODO: are these always inserted in order?
runSql dbpool $ do
insert ping
last <- selectFirst
[TrainAnchorTrip ==. runningTrip, TrainAnchorDay ==. runningDay]
[Desc TrainAnchorWhen]
-- only insert new estimates if they've actually changed anything
when (fmap (trainAnchorDelay . entityVal) last /= Just (trainAnchorDelay anchor))
$ void $ insert anchor
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 $ trainPingToken ping)
void $ runSql dbpool $ insert ping
handleDebugState = do
now <- liftIO getCurrentTime
runSql dbpool $ do
running <- selectList [RunningBlocked ==. False, RunningExpires >=. now] []
pairs <- forM running $ \(Entity token@(RunningKey uuid) _) -> do
entities <- selectList [TrainPingToken ==. token] []
pure (uuid, fmap entityVal entities)
pure (M.fromList pairs)
handleDebugTrain tripId day = do
unless (runsOnDay gtfs tripId day)
$ sendErrorMsg ("this trip does not run on "+|day|+".")
runSql dbpool $ do
tokens <- selectList [RunningTrip ==. tripId, RunningDay ==. day] []
pings <- forM tokens $ \(Entity token _) -> do
selectList [TrainPingToken ==. token] [] <&> fmap entityVal
pure (concat pings)
handleDebugAPI = pure $ toSwagger (Proxy @API)
-- TODO: proper debug logging for expired tokens
checkTokenValid :: Pool SqlBackend -> Token -> Handler Running
checkTokenValid dbpool token = do
trip <- try $ runSql dbpool $ get (coerce token)
when (runningBlocked trip)
$ throwError err401
whenM (hasExpired (runningExpires trip))
$ throwError err401
pure trip
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
|
