KeepAliveInterval doesn't seem to work

[aspnet-hello]

From @nehmebilal on Thursday, October 5, 2017 9:54:50 AM

In my StartUp class of ASP.Net app hosted using WebListener, I am adding the WebSocketMiddleware as follows:

            var webSocketOptions = new WebSocketOptions
            {
                KeepAliveInterval = TimeSpan.FromSeconds(30),
            };
            app.UseWebSockets(webSocketOptions);

Then I am creating WebSockets as follows:

        public async Task Configure(HttpContext hc, Func<Task> next)
        {
           var webSocket = hc.WebSockets.AcceptWebSocketAsync();
           /// ...
        }

The value I use for KeepAliveInterval doesn't seem to have any effect and it still seems to take up to 2 minutes to send a ping.

I am currently using Microsoft.AspNetCore.WebSockets 1.0.2.

Am I doing anything wrong?

Copied from original issue: aspnet/WebSockets#204

[aspnet-hello]

From @Tratcher on Thursday, October 5, 2017 10:08:00 AM

Takes up to 2 minutes for what? To send a Ping?

[aspnet-hello]

From @nehmebilal on Thursday, October 5, 2017 10:08:43 AM

Yes (description updated).

[aspnet-hello]

From @nehmebilal on Friday, October 6, 2017 8:43:37 AM

Any thoughts?

[aspnet-hello]

From @Tratcher on Wednesday, October 11, 2017 10:41:53 AM

The relevant code:
https://github.com/aspnet/WebSockets/blob/c65e8681c4a50fc33c263d1f42dfcf007cb5c035/src/Microsoft.AspNetCore.WebSockets/Internal/fx/src/System.Net.WebSockets.Client/src/System/Net/WebSockets/ManagedWebSocket.cs#L487-L501
It does have that else clause that says it will skip sending a Ping if any other send is already in progress.

[aspnet-hello]

From @nehmebilal on Wednesday, October 11, 2017 10:51:23 AM

Ok. In my experiments, there was pretty much no traffic other than the pings so there shouldn't be any contention on the lock.

Is it possible that the options passed through app.UseWebSockets(options) is not making it to the ManagedWebSocket?

[jektvik]

Have just been playing with the websocket basically deploying this demo implementation locally: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/websockets?view=aspnetcore-2.0
and I find that there are no ping frames sent through what-so-ever. Have actually tested it by connecting another machine and pulling its network cable -> 10 minutes later it's still registering as a connected user to the server. These are my settings:

var webSocketOptions = new WebSocketOptions()
        {
            KeepAliveInterval = TimeSpan.FromSeconds(1),
            ReceiveBufferSize = 4 * 1024
        };
        app.UseWebSockets(webSocketOptions);

And these are my versions:
Versions used - AspNetCore.All (2.0.7) -> WebSockets (2.0.2)

[Tratcher]

Which server? There are some known issues for IIS/Express.

[jektvik]

tested on:
IIS express 10.0.14358.10000
IIS 10.0.17134.1

[Tratcher]

@pan-wang keep alives aren't forwarded through IIS/ANCM, right? Is there any way to control IIS's outbound websocket keep alives?

[pan-wang]

can you try config the ping interval of the IIS application to see whether it helps?
https://docs.microsoft.com/en-us/iis/configuration/system.webserver/websocket.

[jektvik]

The applicationHost.config has by default this:
<section name="webSocket" overrideModeDefault="Deny" />
which is causing:

This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false".

however, once it's changed to 'allow', and the app starts with the altered web.config, there are still no pings being received (note: I'm now looking at frames in chrome dev-tools only )

[pan-wang]

@jekusz browser dev-tool will not show websocket ping/pong. You need install wireshark. After filter websocket.payload.ping, you will see there are ping/pong between browser and server.

[jektvik]

@pan-wang
On the modified web.config, -> I am getting websocket pingpong in wireshark indeed. The timing is very strange (it seems to be double to what its set in web.config). They stop after a few minutes though.
On the original web.config (i.e. without the websocket tag) -> using wireshark, i dont get any ping at any point.
I don't see any effect of the KeepAliveInterval setting on anything.