TelnetNegotiationCore.Gmcp 4.5.3

TelnetNegotiationCore.Gmcp

The standard GMCP packages for MUD clients and servers: the Core package (Core.Hello, Core.Supports.Set/Add/Remove, Core.Ping, Core.KeepAlive, Core.Goodbye), and typed messages for Client.Media, Client.GUI, Client.Map, Char.Login (version 2, as Mudlet speaks it), External.Discord, IRE.Composer, Char.Vitals, Char.Items, Char.Skills, Char.Afflictions, Char.Defences, Room.Info, Comm.Channel.Text, and the MUD Standards mudstd.* proposals.

It does not depend on TelnetNegotiationCore. A session takes a GmcpSend delegate to send with and is handed each received message, so it works over any GMCP transport. TelnetNegotiationCore wires one up in a call:

var telnet = await builder
    .AddPlugin<GMCPProtocol>().UseGmcpServerSession(out var gmcp)
    .BuildAsync();

// Later, from the game:
if (gmcp.Supports("Char.Vitals"))
{
    await gmcp.SendAsync("Char.Vitals", """{"hp":100,"maxhp":120}""");
}

GmcpServerSession records the client's name and version from Core.Hello, keeps the module list from Core.Supports, answers Core.Ping, reports Core.KeepAlive, sends Core.Goodbye, and passes every other message to OnMessageAsync. Supports("Char.Vitals") is true when the client listed Char.Vitals or Char.

GmcpClientSession sends Core.Hello and the Core.Supports messages, times Core.Ping round trips, and reports Core.Goodbye. With TelnetNegotiationCore, UseGmcpClientSession sends Core.Hello from WithClientIdentity and Core.Supports.Set as soon as GMCP is agreed:

var telnet = await new TelnetInterpreterBuilder()
    .UseMode(TelnetInterpreter.TelnetMode.Client)
    .WithClientIdentity("MyClient", "1.0")
    .AddPlugin<GMCPProtocol>()
        .UseGmcpClientSession(out var gmcp, new("Char", 1), new("Room", 1))
    .BuildAsync();

Over another transport, call HelloAsync and SetSupportsAsync yourself when GMCP is agreed.

Typed messages have ToJson() and TryParse, and either session sends one with SendAsync(message):

await gmcp.SendAsync(new CharVitals { Hp = 100, MaxHp = 120 });

Other Char.* packages have no agreed keys between servers. GmcpPackages names them, and the game sends its own JSON.

MsdpNames holds the MSDP command, list and variable names from the MSDP specification (MsdpNames.Command.Report, MsdpNames.Character.HealthMax, MsdpNames.Mapping.Room), and MsdpNames.GmcpPackage, the MSDP package that carries MSDP over GMCP.