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{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE ExplicitNamespaces #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TypeApplications #-}
-- Implementation of the API. This module is the main point of the program.
module Server (application) where
import Conduit (MonadTrans (lift), ResourceT)
import Control.Concurrent.STM
import Control.Monad (when)
import Control.Monad.Extra (whenM)
import Control.Monad.IO.Class (MonadIO (liftIO))
import Control.Monad.Logger.CallStack (NoLoggingT)
import Control.Monad.Reader (forM)
import Control.Monad.Trans.Maybe (MaybeT (..))
import Data.Aeson (FromJSON (parseJSON),
ToJSON (toJSON), ToJSONKey,
genericParseJSON,
genericToJSON)
import qualified Data.Aeson as A
import Data.Coerce (coerce)
import Data.Functor ((<&>))
import Data.Map (Map)
import qualified Data.Map as M
import Data.Pool (Pool)
import Data.Proxy (Proxy (Proxy))
import Data.Swagger hiding (get)
import Data.Text (Text)
import Data.Time (NominalDiffTime,
UTCTime (utctDay), addUTCTime,
dayOfWeek, diffUTCTime,
getCurrentTime, nominalDay)
import Data.UUID (UUID)
import qualified Data.UUID as UUID
import qualified Data.UUID.V4 as UUID
import Data.Vector (Vector)
import Database.Persist
import Database.Persist.Postgresql
import GHC.Generics (Generic)
import GTFS
import Servant (Application,
FromHttpApiData (parseUrlPiece),
Server, err401, err404, serve,
throwError)
import Servant.API (Capture, FromHttpApiData, Get,
JSON, Post, ReqBody,
type (:<|>) ((:<|>)))
import Servant.Docs (DocCapture (..),
DocQueryParam (..),
ParamKind (..), ToCapture (..),
ToParam (..))
import Servant.Server (Handler)
import Servant.Swagger (toSwagger)
import Web.PathPieces (PathPiece)
import API
import Persist
application :: GTFS -> Pool SqlBackend -> IO Application
application gtfs dbpool = do
doMigration dbpool
pure $ serve (Proxy @CompleteAPI) $ 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 -> Server CompleteAPI
server gtfs@GTFS{..} dbpool = handleDebugAPI :<|> handleStations :<|> handleTimetable :<|> handleTrip
:<|> handleRegister :<|> handleTripPing :<|> handleDebugState
where handleStations = pure stations
handleTimetable station = do
-- TODO: resolve "overlay" trips (perhaps just additional CalendarDates?)
today <- liftIO getCurrentTime <&> utctDay
pure $ tripsOnDay gtfs today
handleTrip trip = case M.lookup trip trips of
Just res -> pure res
Nothing -> throwError err404
handleRegister tripID = do
expires <- liftIO $ getCurrentTime <&> addUTCTime validityPeriod
RunningTripKey token <- runSql dbpool $ insert (RunningTrip expires False tripID)
pure token
handleTripPing ping = do
checkTokenValid dbpool (coerce $ tripPingToken ping)
-- TODO: are these always inserted in order?
runSql dbpool $ insert ping
pure ()
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)
-- 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
|
