Pre-upgraded WebSocket transport perpetually connects when AutoUpgrade is true

[ladenedge]

In v3, I used the following configuration:

Transport = TransportProtocol.WebSocket,
AutoUpgrade = true,

In v4, this seems to lead to an infinite connect loop:

Tracing through the code, it looks like we try to auto-upgrade regardless of whether the transport is already set to WebSocket:

socket.io-client-csharp/src/SocketIOClient/SocketIO.cs

Lines 365 to 380 in bddf159

	private async Task HandleOpenedMessage(IMessage message)
	{
	if (!Options.AutoUpgrade)
	{
	return;
	}
	var openedMessage = (OpenedMessage)message;
	if (!openedMessage.Upgrades.Contains("websocket"))
	{
	return;
	}
	Options.Transport = TransportProtocol.WebSocket;
	await UpgradeTransportAsync(openedMessage).ConfigureAwait(false);
	}

And for some reason, it never breaks out of trying to auto-upgrade the new connection.

The workaround for this problem is simply turning off AutoUpgrade:

AutoUpgrade = false,

However, it does seem like this is a bug. We should either not attempt to upgrade WebSocket transports, or figure out why it doesn't break out of that connect loop. Or both! :)

[doghappy]

Thank you @ladenedge , but I can't reproduce it. Could you please provide more details about the reproduction code for both the client and server?

[ladenedge]

Well, I'm using a custom-built, barebones C# socket.io server, so it doesn't support auto-upgrade. That's why I'm starting with Transport = WebSocket. I'm sure my issue is related to something I'm doing wrong on the server side. For instance my connection packet looks like this:

0{"pingInterval":25000,"pingTimeout":5000,"upgrades":["websocket"],"sid":"37a8a10d"}

Perhaps the fact that my WebSocket transport is providing a "websocket" upgrade is leading to the infinite loop. I guess it still feels a bit funny to respect the "AutoUpgrade" even when Transport == WebSocket, but I'm happy to close this issue out as a badly implemented server.

Thank you very much for your time and prompt attention!

[doghappy]

If a WebSocket connection is already being used to connect to the Socket.IO server, the upgrade array should not contain websocket. This is what I observed from the Socket.IO JavaScript server implementation.

However, regardless of this, the library should still handle this edge case. I will fix it. Thanks :)

[doghappy]

The issue is fixed. please pull the latest code

[ladenedge]

This works. Thanks for your time and attention!