WebSocketClient's KeepAliveInterval can't be disabled.

[Nyatra]

In console window (OnLogMessage from DiscordBot):
[Gateway] Disconnected: Received close code 4002: Error while decoding payload.

In Visual Studio output window:

Exception thrown: 'Discord.Net.WebSocketException' in Discord.Net.dll
Exception thrown: 'System.Threading.Tasks.TaskCanceledException' in mscorlib.ni.dll
Exception thrown: 'System.Threading.Tasks.TaskCanceledException' in mscorlib.ni.dll
Exception thrown: 'Discord.Net.WebSocketException' in mscorlib.ni.dll

This occurs every 32.5 seconds when there is absolutely no activity in connected channels.
With activity, this does not occur.

After disconnecting, Discord.Net reconnects and, if there is still no activity, it disconnects again after 32.5 seconds.

Guessing it has something to do with the heartbeat.

Using .Net Core RC2. Latest master branch from GitHub.

project.json:

{
    "version": "1.0.0-*",
    "buildOptions": {
        "emitEntryPoint": true
    },

    "dependencies": {
        "Newtonsoft.Json": "8.0.4-beta1",
        "Discord.Net": "0.9.2"
    },

    "frameworks": {
        "netstandard1.5": {
            "imports": [
                "portable-net451+win81"
            ]
        }
    },

    "runtimes": {
        "win81-x64": { }
    }
}

Program.cs:

using System;
using System.Text;
using Discord;

namespace InactivityIssue
{
    public class Program
    {
        public static void Main(string[] args) => new Program().Start();

        private DiscordClient _client;

        public void Start()
        {
            _client = new DiscordClient(x =>
            {
                x.LogLevel = LogSeverity.Debug;
                x.LogHandler = OnLogMessage;
            });

            _client.ExecuteAndWait(async () =>
            {
                await _client.Connect("BOTTOKEN");
            });
        }

        private void OnLogMessage(object sender, LogMessageEventArgs e)
        {
            //Color
            ConsoleColor color;
            switch (e.Severity)
            {
                case LogSeverity.Error: color = ConsoleColor.Red; break;
                case LogSeverity.Warning: color = ConsoleColor.Yellow; break;
                case LogSeverity.Info: color = ConsoleColor.White; break;
                case LogSeverity.Verbose: color = ConsoleColor.Gray; break;
                case LogSeverity.Debug: default: color = ConsoleColor.DarkGray; break;
            }

            //Exception
            string exMessage;
            Exception ex = e.Exception;
            if (ex != null)
            {
                while (ex is AggregateException && ex.InnerException != null)
                    ex = ex.InnerException;
                exMessage = ex.Message;
            }
            else
                exMessage = null;

            //Source
            string sourceName = e.Source?.ToString();

            //Text
            string text;
            if (e.Message == null)
            {
                text = exMessage ?? "";
                exMessage = null;
            }
            else
                text = e.Message;

            //Build message
            StringBuilder builder = new StringBuilder(text.Length + (sourceName?.Length ?? 0) + (exMessage?.Length ?? 0) + 5);
            if (sourceName != null)
            {
                builder.Append('[');
                builder.Append(sourceName);
                builder.Append("] ");
            }
            for (int i = 0; i < text.Length; i++)
            {
                //Strip control chars
                char c = text[i];
                if (!char.IsControl(c))
                    builder.Append(c);
            }
            if (exMessage != null)
            {
                builder.Append(": ");
                builder.Append(exMessage);
            }

            text = builder.ToString();
            Console.ForegroundColor = color;
            Console.WriteLine(text);
        }
    }
}

[Auralytical]

If this is running on a Linux/OSX box, be sure to add the Discord gateway cert:
certmgr -ssl https://gateway.discord.gg

[foxbot]

Unable to Reproduce;

Copied your project.json, Program.cs
Using Discord.Net 0.9.2 from NuGet.
dotnet 1.0.0-preview1-002702

[Nyatra]

I'm using:

• Windows 10 Pro 64bit
• Visual Studio 2015 Community
• 1.0.0-preview1-002702
• Latest version of Discord.net from the master branch on GitHub

I've attached the project with the issue. InactivityIssue.zip

Folder structure:
YourProjectsFolder\Discord.Net\src\Discord.Net
YourProjectsFolder\InactivityIssue\

I get the same issue when I dotnet publish -c Release and run it on a remote Windows Server 2012.

[Auralytical]

Thanks, I was able to reproduce with your project, looking into it.

[Auralytical]

This appears to be tied to WebSocketClient's built-in KeepAliveInterval, which runs every 30 seconds of no activity.

I tried disabling it on my end, but if you look at https://github.com/dotnet/corefx/blob/master/src/System.Net.WebSockets.Client/src/System/Net/WebSockets/ClientWebSocketOptions.cs#L131 - I don't see this option being used anywhere.

EDIT: Found an issue for this: https://github.com/dotnet/corefx/issues/5116

[Xeevis]

This can be really frustrating issue as bot on low traffic guilds is coming on/off all the time missing commands and events. I've managed to over come this by deploying to docker on Synology NAS (any Linux environment should work), where it works flawlessly.

Since stable release of WebSockets.Client doesn't support unix yet, it's necessary to download latest beta version from https://dotnet.myget.org/feed/dotnet-core/package/nuget/System.Net.WebSockets.Client

Or bump Discord.Net/projects.json dependency to

"System.Net.WebSockets.Client": "4.0.1-beta*",

(this requires adding MyGet into NuGet package sources)

https://dotnet.myget.org/F/dotnet-core/api/v3/index.json

[Nyatra]

The way I worked around the issue on Windows for now, is by setting the global Keep-alive Interval in the registry to something really large.

HKLM:\Software\Microsoft\WebSocket\KeepaliveInterval

It's should be a DWORD, if it does not exist already.

This will affect anything that uses the global setting and does not have it's own setting. (All .NET Core WebSockets currently)

I found this in an msdn page:

WINHTTP_OPTION_WEB_SOCKET_KEEPALIVE_INTERVAL

Sets the interval, in milliseconds, to send a keep-alive packet over the connection. The default interval is 30000 (30 seconds). The minimum interval is 15000 (15 seconds). Using WinHttpSetOption to set a value lower than 15000 will return with ERROR_INVALID_PARAMETER.

Note The default value for WINHTTP_OPTION_WEB_SOCKET_KEEPALIVE_INTERVAL is read from HKLM:\SOFTWARE\Microsoft\WebSocket\KeepaliveInterval. If a value is not set, the default value of 30000 will be used. It is not possible to have a lower keepalive interval than 15000 milliseconds.

[Auralytical]

I've talked to Discord about this, and they're going to fix this sometime on their end, adding support for keepalive packets. @jhgg

[Auralytical]

This fix is live.