Server Timeout in JavaScript Client doesnt work as expected

[ottohak]

Hi guys,

I am currently developing an internal application that needs to know when the connection to my SignalR server is lost. My goal is to react to a lost connection in up to 3 seconds.

So I set the serverTimeoutInMilliseconds to 3000 and the 'KeepAliveInterval' to TimeSpan.FromSeconds(1).

But this doesn't work as expected. For a test I send every second a message to the client, when I walk far enough away from my WiFi access point my Surface stops getting messages for 20+ seconds and then I am getting a onclose event.

If test this with my Android Phone running Chrome the onclose message is almost immediately fired when the signal is lost.

Maybe this this the way Windows handles lost network connections, but if I set the serverTimeoutInMilliseconds this shouldn't be a problem, right?

Thanks for this great project!

Please include as much of the following as you can in your bug report

• Versions of Server-Side NuGet Packages: tried 1.0.0 and 1.0.1
• Versions of Client-Side NuGet/NPM Packages: 1.0.0
• Are you using the C# client or the JavaScript client: Javascript
• The Server you are using (Kestrel/HttpSysServer/IIS/IIS Express/Azure Web App/etc.): Visual Studio Debug so I think Kestrel
• The Operating System on the Server (Windows/Linux/macOS): Windows
• The Operating System on the Client (Windows/Linux/macOS): Windows 10
• The Browser on the client, if using the JavaScript client (IE/Chrome/Edge/Firefox/etc.): Firefox 60 and Chrome 67
• Please use the Diagnostics Guide at https://github.com/aspnet/SignalR/wiki/Diagnostics-Guide to collect server-side and client-side logs and network traces if possible. Please do not put the traces and logs in the Issue text as they are quite large. The Diagnostics Guide describes how to attach them to the issue. Chrome_IP_Removed.txt

When in doubt, feel free to file the issue, we're happy to help answer questions. We also suggest using the asp.net-core-signalr tag on StackOverflow to ask questions.

[BrennanConroy]

The HAR file you gave didn't complete the handshake request so it's not even running the code that makes use of serverTimeoutInMilliseconds. Could you try your scenario again but collect logs from a connection that actually connects?

[ottohak]

Okay, I hope the .har file is complete now. SecondTry.txt

This is the way I connect to the SignalR Server: https://github.com/ottohak/SignalR-Test/blob/master/src/app/app.component.ts

Edit: Firefox .har file: Archive 18-06-29 10-07-14.txt

[BrennanConroy]

Those HAR files are basically the same as the first one.

Lets try something different. Could you turn on logging on the javascript client https://github.com/aspnet/SignalR/wiki/Diagnostics-Guide#javascript-client-logging

Also, it would be nice to see how you are sending messages every second to the client from the server, and where does the client receive those messages?

[analogrelay]

One problem, which I should update the Diagnostics Guide to note, is that it looks like the browser dev tools don't include WebSocket frames in the network traces. You could try using Fiddler to get more detailed traces. Having the extra logging @BrennanConroy mentioned is also very useful as it will tell us what's going on in the client when it terminates the connection.

[ottohak]

Chrome Console Log: Log Traces.txt Fiddler Traces: Traces.saz.txt I hope I used Fiddler the right way, I wasn't sure what to look for.

@BrennanConroy I added the code how I receive the messages: https://github.com/ottohak/SignalR-Test/blob/master/src/app/app.component.ts#L37 This is basically how I send these messages:

signalHub.Clients.Clients(clients).SendAsync("Event", clientMessageData.Data);

Edit: This is how I added SignalR to my Server:

services.AddSignalR(options =>
{
  options.KeepAliveInterval = TimeSpan.FromSeconds(1);
});

[BrennanConroy]

I tried a simple test on a windows machine and couldn't repro. Although instead of walking away from a WIFI connection I SIGKILLed the server process which the OS might still try to gracefully close client connections.

[ottohak]

Yeah, to easily reproduce this issue I used a Surface Ethernet Adapter (https://www.microsoft.com/en-us/p/surface-usb-30-gigabit-ethernet-adapter/8xn9fqvzbvq0?activetab=pivot:techspecstab).

When I disconnect the USB Plug the Connection is lost immediately. Disabling the Network Connection in the Network Settings of Windows was always an immediate Connection lose (I think this happens when the USB Plug is disconnected).

But when I remove the Ethernet cable the connections waits 20 Seconds.

[BrennanConroy]

Perfect, I can repro this when unplugging the ethernet cord.

I'll investigate some more, but it looks like the timeout is being called within the 3 seconds, it might be the Websocket close that takes so long.

[BrennanConroy]

WebSocket.close() is taking 18+ seconds by itself and we call the connections onclose callback in the WebSocket.onclose event.

We can consider calling the callback in the close method on server timeouts to alert the user sooner.

[BrennanConroy]

Fixed via https://github.com/aspnet/SignalR/commit/53ceaf1b2c29aaa22a0c039609e2b34e27120396