halogen-websocket-ipc-playzone/src/App/WS.purs

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module App.WS where
{- This component handles all WS operations. -}
import Prelude (Unit, bind, discard, pure, show, void, when, ($), (&&), (<$>), (<>), (>>=), (>=>), (<<<), map)
import Control.Monad.Except (runExcept)
import Data.Array as A
import Data.ArrayBuffer.Types (ArrayBuffer)
import Data.Bifunctor (lmap)
import Data.Either (Either(..))
import Data.Maybe (Maybe(..), isJust, isNothing)
import Data.String as String
import Data.Tuple (Tuple(..))
import Effect.Aff.Class (class MonadAff)
import Effect (Effect)
import Foreign as F
import Halogen as H
import Halogen.HTML as HH
import Halogen.HTML.Events as HE
import Halogen.HTML.Properties as HP
import Halogen.Query.Event as HQE
import Halogen.Subscription as HS
import Web.Socket.BinaryType (BinaryType(ArrayBuffer))
import Web.Socket.Event.CloseEvent as WSCE
import Web.Socket.Event.EventTypes as WSET
import Web.Socket.Event.MessageEvent as WSME
import Web.Socket.ReadyState (ReadyState(Connecting, Open, Closing, Closed))
import Web.Socket.WebSocket as WS
import App.LogMessage
-- Input is the WS url.
type Input = String
-- MessageReceived (Tuple URL message)
data Output
= MessageReceived (Tuple String ArrayBuffer) -- Provide a received message to the parent.
| WSJustConnected -- Inform the parent the connection is up.
| WSJustClosed -- Inform the parent the connection is down.
| Log LogMessage
type Slot = H.Slot Query Output
data Query a
= ToSend ArrayBuffer a
data Action
= Initialize
| WebSocketParseError String
| ConnectWebSocket
| SendMessage ArrayBuffer
| Finalize
| HandleWebSocket (WebSocketEvent WebSocketMessageType)
type WSInfo
= { url :: String
, connection :: Maybe WS.WebSocket
, reconnect :: Boolean
}
type State = { wsInfo :: WSInfo }
component :: forall m. MonadAff m => H.Component Query Input Output m
component =
H.mkComponent
{ initialState
, render
, eval: H.mkEval $ H.defaultEval
{ initialize = Just Initialize
, handleAction = handleAction
, handleQuery = handleQuery
, finalize = Just Finalize
}
}
initialState :: Input -> State
initialState url =
{ wsInfo: { url: url
, connection: Nothing
, reconnect: false
}
}
render :: forall m. State -> H.ComponentHTML Action () m
render { wsInfo }
= HH.div_
[ renderReconnectButton (isNothing wsInfo.connection && wsInfo.reconnect)
]
where
renderFootnote :: String -> H.ComponentHTML Action () m
renderFootnote txt =
HH.div [ HP.style "margin-bottom: 0.125rem; color: grey;" ] [ HH.small_ [ HH.text txt ] ]
renderReconnectButton :: Boolean -> H.ComponentHTML Action () m
renderReconnectButton cond =
if cond
then
HH.p_
[ HH.button
[ HP.type_ HP.ButtonButton
, HE.onClick \_ -> ConnectWebSocket
]
[ HH.text "Reconnect?" ]
]
else
HH.p_
[ renderFootnote "NOTE: A 'Reconnect?' button will appear if the connection drops"
]
handleAction :: forall m. MonadAff m => Action -> H.HalogenM State Action () Output m Unit
handleAction action = do
{ wsInfo } <- H.get
case action of
Initialize ->
handleAction ConnectWebSocket
Finalize -> do
-- H.raise $ Log $ SystemLog $ "Closing websocket for '" <> wsInfo.url <> "'"
case wsInfo.connection of
Nothing -> H.raise $ Log $ SystemLog "No socket? How is that even possible?"
Just socket -> H.liftEffect $ WS.close socket
WebSocketParseError error ->
H.raise $ Log $ SystemLog $ renderError (UnknownError error)
ConnectWebSocket -> do
-- H.raise $ Log $ SystemLog $ "Connecting to \"" <> wsInfo.url <> "\"..."
webSocket <- H.liftEffect $ WS.create wsInfo.url []
H.liftEffect $ WS.setBinaryType webSocket ArrayBuffer
H.modify_ _ { wsInfo { connection = Just webSocket } }
void $ H.subscribe (HandleWebSocket <$> webSocketEmitter webSocket)
SendMessage array_buffer_to_send -> do
case wsInfo.connection of
Nothing -> H.raise $ Log $ SimpleLog $ "[🤖] Can't send a message, websocket is down!"
Just webSocket -> H.liftEffect $ do
sendArrayBuffer webSocket array_buffer_to_send
HandleWebSocket wsEvent -> do
case wsEvent of
WebSocketMessage received_message -> do
-- H.raise $ Log $ SimpleLog $ "[😈] Received a message"
H.raise $ MessageReceived $ Tuple wsInfo.url received_message.message
WebSocketOpen -> do
-- H.raise $ Log $ SystemLog ("Successfully connected to \"" <> wsInfo.url <> "\"!🎉")
H.raise $ WSJustConnected
WebSocketClose { code, reason, wasClean } -> do
H.raise $ Log $ SystemLog $ renderCloseMessage code wasClean reason
maybeCurrentConnection <- H.gets _.wsInfo.connection
when (isJust maybeCurrentConnection) do
H.modify_ _ { wsInfo { connection = Nothing, reconnect = true } }
H.raise $ WSJustClosed
WebSocketError errorType ->
H.raise $ Log $ SystemLog $ renderError errorType
-- TODO: MAYBE inform the parent the connection is closed (if it's the case).
where
renderCloseMessage
:: Int
-> Boolean
-> String
-> String
renderCloseMessage code wasClean = case _ of
"" -> baseCloseMessage
reason -> baseCloseMessage <> "Reason: " <> reason
where
baseCloseMessage :: String
baseCloseMessage =
String.joinWith " "
[ "Connection to WebSocket closed"
, "[ CODE:" , show code , "|" , if wasClean then "CLEAN" else "DIRTY" , "]"
]
handleQuery :: forall a m. MonadAff m => Query a -> H.HalogenM State Action () Output m (Maybe a)
handleQuery = case _ of
ToSend message a -> do
{ wsInfo } <- H.get
case wsInfo.connection of
Nothing -> do
H.raise $ Log $ UnableToSend "Not connected to server."
pure Nothing
Just webSocket -> do
H.liftEffect (WS.readyState webSocket) >>= case _ of
Connecting -> do
H.raise $ Log $ UnableToSend "Still connecting to server."
pure Nothing
Closing -> do
H.raise $ Log $ UnableToSend "Connection to server is closing."
pure Nothing
Closed -> do
H.raise $ Log $ UnableToSend "Connection to server has been closed."
maybeCurrentConnection <- H.gets _.wsInfo.connection
when (isJust maybeCurrentConnection) do
H.modify_ _ { wsInfo { connection = Nothing, reconnect = true } }
pure Nothing
Open -> do
H.liftEffect $ do
sendArrayBuffer webSocket message
pure (Just a)
--------------------------------------------------------------------------------
-- WebSocket mess.
--------------------------------------------------------------------------------
data WebSocketEvent :: Type -> Type
data WebSocketEvent msg
= WebSocketMessage { message :: msg, origin :: String, lastEventId :: String }
| WebSocketOpen
| WebSocketClose { code :: Int, reason :: String, wasClean :: Boolean }
| WebSocketError ErrorType
webSocketEmitter :: WS.WebSocket -> HS.Emitter (WebSocketEvent WebSocketMessageType)
webSocketEmitter socket = do
HS.makeEmitter \push -> do
openId <- HS.subscribe openEmitter push
errorId <- HS.subscribe errorEmitter push
closeId <- HS.subscribe closeEmitter push
messageId <- HS.subscribe messageEmitter push
pure do
HS.unsubscribe openId
HS.unsubscribe errorId
HS.unsubscribe closeId
HS.unsubscribe messageId
where
target = WS.toEventTarget socket
openEmitter :: HS.Emitter (WebSocketEvent WebSocketMessageType)
openEmitter =
HQE.eventListener WSET.onOpen target \_ ->
Just WebSocketOpen
errorEmitter :: HS.Emitter (WebSocketEvent WebSocketMessageType)
errorEmitter =
HQE.eventListener WSET.onError target \_ ->
Just (WebSocketError UnknownWebSocketError)
closeEmitter :: HS.Emitter (WebSocketEvent WebSocketMessageType)
closeEmitter =
HQE.eventListener WSET.onClose target \event ->
WSCE.fromEvent event >>= \closeEvent ->
Just $ WebSocketClose { code: WSCE.code closeEvent
, reason: WSCE.reason closeEvent
, wasClean: WSCE.wasClean closeEvent
}
messageEmitter :: HS.Emitter (WebSocketEvent WebSocketMessageType)
messageEmitter = HQE.eventListener WSET.onMessage target (WSME.fromEvent >=> decodeMessageEvent)
decodeMessageEvent :: WSME.MessageEvent -> Maybe (WebSocketEvent WebSocketMessageType)
decodeMessageEvent = \msgEvent -> do
let
foreign' :: F.Foreign
foreign' = WSME.data_ msgEvent
case foreignToArrayBuffer foreign' of
Left errs -> pure $ WebSocketError $ UnknownError errs
Right arrayBuffer -> pure $ WebSocketMessage { message: arrayBuffer
, origin: WSME.origin msgEvent
, lastEventId: WSME.lastEventId msgEvent }
---------------------------
-- Errors
---------------------------
data ErrorType
= UnknownError String
| UnknownWebSocketError
renderError :: ErrorType -> String
renderError = case _ of
UnknownError str ->
"Unknown error: " <> str
UnknownWebSocketError ->
"Unknown 'error' event has been fired by WebSocket event listener"
--------------------------------------------------------------------------------
-- WebSocket message type
--------------------------------------------------------------------------------
type WebSocketMessageType = ArrayBuffer
sendArrayBuffer :: WS.WebSocket -> ArrayBuffer -> Effect Unit
sendArrayBuffer = WS.sendArrayBuffer
foreignToArrayBuffer :: F.Foreign -> Either String ArrayBuffer
foreignToArrayBuffer
= lmap renderForeignErrors
<<< runExcept
<<< F.unsafeReadTagged "ArrayBuffer"
where
renderForeignErrors :: F.MultipleErrors -> String
renderForeignErrors =
String.joinWith "; " <<< A.fromFoldable <<< map F.renderForeignError