1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE TypeSynonymInstances #-}
{-# LANGUAGE UndecidableInstances #-}
module Server 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, type (:>))
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 uuid <- runSql dbpool $ insert (RunningTrip expires False tripID)
pure (Token uuid)
handleTripPing ping = do
checkTokenValid dbpool (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 (RunningTripKey uuid) _) -> do
entities <- selectList [TripPingToken ==. Token uuid] []
pure (Token uuid, fmap entityVal entities)
pure (M.fromList pairs)
handleDebugAPI = pure $ toSwagger (Proxy @API)
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
{-
TODO:
there should be a basic API allowing the questions:
- what are the next trips leaving from $station? (or $geolocation?)
- all stops of a given tripID
then the "ingress" API:
- train ping (location, estimated delay, etc.)
- cancel trip
- add trip?
-}
|
