moesenle / servant-websockets Goto Github PK

Nice package! Thanks.

Warning: I'm fairly new to Haskell.

Right now, I assume an exception of some sort is thrown because a 500 error is returned and subsequently logged when a client disconnects.

I would like to either handle that exception myself or get notified of the disconnection. Either way, I'd rather that a 500 error wasn't sent/logged.

Thanks.

Hello,
I've run into the issue specific to just Firefox with servant 0.15.

This is an error is thrown in Firefox on new WebScoket()

Firefox can’t establish a connection to the server at ws://localhost:foo/bar

I've tested examples in master (using lts-9.0) and it works with servant version from this snapshot.
I've tested chrome with stackage updated to lts-12.26 and this case works as well.

table of compatibility:

I have no idea what exactly this is about and how it can be fixed (at least not yet).

The issue can be tested by applying this patch
turboMaCk@3b133b0

and following:

$ stack build
$ stack exec websocket-stream

and opening index.html in Firefox.

Firefox version: 64.0
OS: Mac/Linux (NixOS)

I don't understand the internals yet but it's clear that the WebSocket type is lacking some instances that Raw has. When trying to wrap servant-auth's Auth combinator around Raw, things work fine. But if I wrap it around WebSocket I get a No instance for (HasServer (AddSetCookieApi (AddSetCookieApi WebSocket)) '[CookieSettings, JWTSettings]).

Would it be possible for ConnectionOptions to be passed in?
Not sure how this would work since it's hidden behind a HasServer instance

Edit: Nevermind, I realized this is configurable via a PendingConnection.

Pairing Servant.Auth authentication with a Servant.WebSockets endpoint yields an overlapping instances error.

    • Overlapping instances for HasServer
                                  (Servant.Auth.Server.Internal.AddSetCookie.AddSetCookieApi
                                     (Servant.Auth.Server.Internal.AddSetCookie.AddSetCookieApi
                                        Servant.API.WebSocket.WebSocketPending))
                                  '[Backend ByteString, CookieSettings, JWTSettings]
        arising from a use of ‘hoistServerWithContext’

This error was mentioned in a comment in #2. Does anyone know how solve this or have an idea on how to start?

Hey, I have been using this library and noticed some inconvenient behavior when adding logging. When adding a logging middleware (any logging middleware should work), and then requesting a connection to the WebSocket, the logs will show a 500 error. The connection is successful, and no other issues seem to exist. I suspect there should an exception being raised somewhere but I am not really sure where.
To test this I used the example provided in the documentation in this library with a basic logger:

import Network.Wai
import Network.Wai.Handler.Warp
import Servant
import Network.WebSockets.Connection (PendingConnection, sendTextData, forkPingThread, acceptRequest)
import Servant.API.WebSocket (WebSocketPending)
import Control.Monad.IO.Class
import Control.Monad
import Data.ByteString.Char8
import Control.Concurrent
import Network.Wai.Middleware.RequestLogger

startApp :: IO ()
startApp = run 8080 app

app :: Application
app = logStdout $ serve api server

api :: Proxy WebSocketApi
api = Proxy

type WebSocketApi = "stream" :> WebSocketPending

server :: Server WebSocketApi
server = streamData
 where
  streamData :: MonadIO m => PendingConnection -> m ()
  streamData pc = do
     c <- liftIO $ acceptRequest pc
     liftIO $ forkPingThread c 10
     liftIO . forM_ [1..] $ \i ->
       sendTextData c (pack $ show (i :: Int)) >> threadDelay 1000000

When connecting to the websocket, the log will show something like this:
127.0.0.1 - - [07/Feb/2022:09:05:21 -0500] "GET /stream HTTP/1.1" 500 - "" ""
where 500 - "" is the response and it represents a HTTP 500 error.

Any help figuring this out is appreciated.