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{-# LANGUAGE DataKinds, OverloadedStrings, TypeOperators, TypeApplications #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TemplateHaskell, QuasiQuotes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FlexibleContexts #-}
module VDV453.Kommunikationsschicht where
import Servant.API
import Servant.Server (Server, serve, Handler, err400)
import Data.Proxy (Proxy(..))
import Network.Wai.Handler.Warp (run)
import Network.HTTP.Media.MediaType ((//))
import Text.XML
import Debug.Trace (trace)
import Fmt
import Text.Hamlet.XML (xml)
import Control.Monad.IO.Class (MonadIO(liftIO))
import Data.Time (getCurrentTime, UTCTime)
import Data.Time.Format.ISO8601 (iso8601Show, iso8601ParseM)
import qualified Data.Text as T
import qualified Data.Map as M
import Network.Wai.Middleware.RequestLogger (OutputFormat (..),
RequestLoggerSettings (..),
mkRequestLogger)
import Data.Functor ((<&>))
import Servant (throwError, ServerError (errBody))
import Data.Typeable (Typeable, typeRep)
import GHC.Stack (HasCallStack, prettyCallStack, callStack, SrcLoc (..))
import GHC.Exts (toList)
import Data.Text (Text)
import GHC.Conc (TVar, newTVar, atomically, readTVar)
import Data.Void (Void, absurd)
import Servant.Client (client, runClientM, BaseUrl (BaseUrl), Scheme (Http), mkClientEnv)
import Network.HTTP.Client (newManager, defaultManagerSettings)
data XML
instance Accept XML where
contentType _ = "text" // "xml"
instance MimeRender XML Element where
mimeRender _ root = renderLBS def (Document (Prologue [] Nothing []) root [])
instance MimeUnrender XML Element where
mimeUnrender _ lbs = case parseLBS def lbs of
Right (Document p root e) ->
trace ("trace: received document: "+|show p|+", _, "+|show e|+".") (Right root)
Left err -> Left (show err)
type VDV a = ReqBody '[XML] a :> Post '[XML] a
type ServerAPI = "status.xml" :> VDV Element
:<|> "aboverwalten.xml" :> VDV Element
:<|> "datenabrufen.xml" :> VDV Element
type ClientAPI = "clientstatus.xml" :> VDV Element
:<|> "datenbereit.xml" :> VDV Element
serverReqStatus :<|> serverReqAboverwalten :<|> serverReqDatenabrufen = client (Proxy @ServerAPI)
clientReqStatus :<|> clientReqDatenbereit = client (Proxy @ClientAPI)
class VDVInfo a where
type Abo a
class VDVInfo s => VDVServer s where
serverAbos :: s -> IO [Abo s]
serverAboAnfrage :: s -> Text -> UTCTime -> [Node] -> IO (Maybe (Int, Text))
serverDatenAbrufen :: s -> Text -> UTCTime -> Bool -> IO (Either (Int, Text) [Node])
-- TODO
class VDVInfo c => VDVClient c where
clientAbos :: c -> IO [Abo c]
clientDatenBereit :: c -> IO ()
class ToElement a where
toElement :: a -> Element
instance ToElement Void where
toElement = absurd
toNodes :: ToElement a => [a] -> [Node]
toNodes = fmap (NodeElement . toElement)
data DumbClient a = DumbClient (TVar [a])
instance VDVInfo (DumbClient a) where
type Abo (DumbClient a) = a
instance VDVClient (DumbClient a) where
clientAbos (DumbClient tvar) = atomically $ readTVar tvar
clientDatenBereit _ = do
putStrLn "neue Daten bereit!"
manager <- newManager defaultManagerSettings
req <- runClientM (serverReqDatenabrufen (Element "hello" mempty []))
(mkClientEnv manager (BaseUrl Http "localhost" 8081 ""))
print req
serverServer :: (VDVServer s) => s -> UTCTime -> Server ServerAPI
serverServer server startupTime = status :<|> aboverwalten :<|> datenabrufen
where status (Element name attrs children) = do
now <- liftIO $ getCurrentTime
-- TODO: no idea what to do with the request information, it doesn't seem relevant at all?
-- TODO: not sure how to decide if DatenBereit is true or false
pure $ Element "StatusAntwort" mempty [xml|
<Status Zst="#{T.pack $ iso8601Show now}">
<DatenBereit>false
<StartDienstZst>#{T.pack $ iso8601Show startupTime}
|]
aboverwalten (Element "AboAnfrage" attrs children) = do
sender <- unwrap (M.lookup "Sender" attrs)
zst <- unwrap (M.lookup "Zst" attrs) >>= (unwrap . iso8601ParseM . T.unpack)
let abos = children
status <- liftIO $ serverAboAnfrage server sender zst abos
now <- liftIO $ getCurrentTime
pure $ Element "AboAntwort" mempty [xml|
$maybe (code, msg) <- status
<Bestaetigung
Zst="#{T.pack $ iso8601Show now}"
Ergebnis="nok"
Fehlernummer="#{T.pack $ show code}"
Fehlertext="#{msg}">
$nothing
<Bestaetigung
Zst="#{T.pack $ iso8601Show now}"
Ergebnis="ok"
Fehlernummer="0">
|]
aboverwalten _ = undefined -- TODO: abo löschen etc.
datenabrufen (Element "DatenAbrufenAnfrage" attrs children) = do
sender <- unwrap (M.lookup "Sender" attrs)
zst <- unwrap (M.lookup "Zst" attrs) >>= (unwrap . iso8601ParseM . T.unpack)
datensatzAlle <- pure True
now <- liftIO $ getCurrentTime
status <- liftIO $ serverDatenAbrufen server sender zst datensatzAlle
case status of
Left (code, msg) -> pure $ Element "DatenAbrufenAntwort" mempty [xml|
<Bestaetigung
Zst="#{T.pack $ iso8601Show now}"
Ergebnis="nok"
Fehlernummer="#{T.pack $ show code}"
Fehlertext="#{msg}">
|]
Right nodes -> pure $ Element "DatenAbrufenAntwort" mempty [xml|
<Bestaetigung
Zst="#{T.pack $ iso8601Show now}"
Ergebnis="ok"
Fehlernummer="0">
<WeitereDaten>false
^{nodes}
|]
datenabrufen _ = throwError err400
clientServer :: (VDVClient c, ToElement (Abo c)) => c -> UTCTime -> Server ClientAPI
clientServer client startupTime = status :<|> datenbereit
where status (Element name attrs children) = do
now <- liftIO $ getCurrentTime
let mitAbos = M.lookup "MitAbos" attrs == Just "true"
abos <- liftIO $ clientAbos client
pure $ Element "ClientStatusAntwort" mempty [xml|
<Status Zst="#{T.pack $ iso8601Show now}" Ergebnis="ok">
<StartDienstZst>#{T.pack $ iso8601Show startupTime}
$if mitAbos
<AktiveAbos>
^{toNodes abos}
|]
datenbereit (Element name attrs children) = do
now <- liftIO $ getCurrentTime
sender <- unwrap $ M.lookup "Sender" attrs
zst :: UTCTime <- unwrap (M.lookup "Zst" attrs)
>>= (unwrap . iso8601ParseM . T.unpack)
-- TODO: fork here? definitely shouldn't hold the answer back …
liftIO $ clientDatenBereit client
pure $ Element "DatenBereitAntwort" mempty [xml|
<Bestaetigung
Zst="#{T.pack $ iso8601Show now}"
Ergebnis="ok"
Fehlernummer="0">
|]
-- | just deny the request if this is Nothing, and print a debug trace instead
unwrap :: forall a. (HasCallStack, Typeable a) => Maybe a -> Handler a
unwrap (Just a) = pure a
unwrap Nothing =
trace ("trace: failed to unwrap a Maybe "+|show (typeRep (Proxy @a))|+" ("+|srcLocModule|+", line "+|srcLocStartLine|+")")
throwError err400
where (_, SrcLoc{..}) = head $ toList callStack
runDumbClient :: IO ()
runDumbClient = do
loggerMiddleware <- mkRequestLogger def { outputFormat = Detailed True }
abos <- atomically $ newTVar (mempty :: [Void])
startupTime <- getCurrentTime
putStrLn ("startup of dumb client at "+|iso8601Show startupTime|+" ...")
run 8080 $ loggerMiddleware $ serve (Proxy @ClientAPI) (clientServer (DumbClient abos) startupTime)
|
