shrub/pkg/king/lib/Vere/Http/Client.hs
Benjamin Summers 55ceffc4c3 CLI parsing.
2019-08-12 21:57:30 -07:00

111 lines
3.3 KiB
Haskell

{-
- TODO When making a request, handle the case where the request id is
already in use.
-}
module Vere.Http.Client where
import ClassyPrelude
import Noun
import Vere.Http
import Arvo (ResponseHeader(..))
import qualified Network.HTTP.Client as H
import qualified Network.HTTP.Types as HT
-- Types -----------------------------------------------------------------------
type ReqId = Word
data Ev = Receive ReqId Event -- [%receive @ todo]
data Eff
= NewReq ReqId Request -- [%request @ todo]
| CancelReq ReqId -- [%cancel-request @]
deriving (Eq, Ord, Show)
data State = State
{ sManager :: H.Manager
, sLive :: TVar (Map ReqId (Async ()))
, sChan :: MVar Ev
}
--------------------------------------------------------------------------------
cvtReq :: Request -> Maybe H.Request
cvtReq r =
H.parseRequest (unpack (unCord $ url r)) <&> \init -> init
{ H.method = encodeUtf8 $ tshow (method r)
, H.requestHeaders = unconvertHeaders (headerList r)
, H.requestBody =
H.RequestBodyBS $ case body r of
Nothing -> ""
Just (Octs bs) -> bs
}
cvtRespHeaders :: H.Response a -> ResponseHeader
cvtRespHeaders resp =
ResponseHeader (fromIntegral $ HT.statusCode (H.responseStatus resp)) heads
where
heads = convertHeaders (H.responseHeaders resp)
--------------------------------------------------------------------------------
initState :: IO State
initState = State <$> H.newManager H.defaultManagerSettings
<*> newTVarIO mempty
<*> newEmptyMVar
emit :: State -> Ev -> IO ()
emit st event = putMVar (sChan st) event
runEff :: State -> Eff -> IO ()
runEff st = \case NewReq id req -> newReq st id req
CancelReq id -> cancelReq st id
newReq :: State -> ReqId -> Request -> IO ()
newReq st id req = do async <- runReq st id req
atomically $ modifyTVar (sLive st) (insertMap id async)
waitCancel :: Async a -> IO (Either SomeException a)
waitCancel async = cancel async >> waitCatch async
cancelThread :: State -> ReqId -> Async a -> IO ()
cancelThread st id =
waitCancel >=> \case Left _ -> emit st (Receive id Canceled)
Right _ -> pure ()
cancelReq :: State -> ReqId -> IO ()
cancelReq st id =
join $ atomically $ do
tbl <- readTVar (sLive st)
case lookup id tbl of
Nothing -> pure (pure ())
Just async -> do writeTVar (sLive st) (deleteMap id tbl)
pure (cancelThread st id async)
runReq :: State -> ReqId -> Request -> IO (Async ())
runReq st id req = async $
case cvtReq req of
Nothing -> emit st (Receive id (Failed "bad-request-e"))
Just r -> H.withResponse r (sManager st) exec
where
recv :: H.BodyReader -> IO (Maybe ByteString)
recv read = read <&> \case chunk | null chunk -> Nothing
| otherwise -> Just chunk
exec :: H.Response H.BodyReader -> IO ()
exec resp = do
let headers = cvtRespHeaders resp
getChunk = recv (H.responseBody resp)
loop = getChunk >>= \case
Nothing -> emit st (Receive id Done)
Just bs -> do emit st (Receive id $ Received $ Octs bs)
loop
emit st (Receive id $ Started headers)
loop