Network Messages

SwiftlyS2's typed net-message API sends generated protobuf messages and intercepts them in both client-to-server and server-to-client directions, through APIISwiftlyCore.NetMessage (APIINetMessageService).

Sending Net Messages

APIINetMessageService.Send builds the message, runs your configure callback, and sends it via the configured recipient filter - use it for one-off sends:

Core.NetMessage.Send<CUserMessageShake>(msg =>
{
    msg.Duration = 1.0f;
    msg.Frequency = 2.0f;
    msg.Amplitude = 0.5f;
    msg.Command = 0;
 
    msg.Recipients.AddAllPlayers();
});

Use APIINetMessageService.Create instead to build the same message shape repeatedly, tweak recipients directly through APIINetMessage`1.Recipients (a APICRecipientFilter), and send with Send()/SendToPlayer/SendToAllPlayers:

using var msg = Core.NetMessage.Create<CUserMessageShake>();
 
msg.Duration = 1.0f;
msg.Frequency = 2.0f;
msg.Amplitude = 0.5f;
msg.Command = 0;
 
msg.Recipients.RemoveAllPlayers();
msg.Recipients.AddRecipient(0);
msg.Recipients.AddRecipient(1);
 
msg.Send(); // or msg.SendToPlayer(0) / msg.SendToAllPlayers()

Hooking Net Messages

Three hook pipelines: client messages (APIINetMessageService.HookClientMessage, client-to-server), server messages (APIINetMessageService.HookServerMessage, server-to-client), and internal server messages (APIINetMessageService.HookServerMessageInternal, server-to-client with a target playerId - only a small subset of server-to-client messages use this pipeline). Each can be registered programmatically or via an attribute discovered on any registered class (your BasePlugin is registered by default).

Client Hooks

private Guid _clientMoveHook;
 
public override void Load(bool hotReload)
{
    _clientMoveHook = Core.NetMessage.HookClientMessage<CCLCMsg_Move>(OnClientMove);
}
 
public override void Unload()
{
    if (_clientMoveHook != Guid.Empty)
        Core.NetMessage.Unhook(_clientMoveHook);
}
 
private HookResult OnClientMove(CCLCMsg_Move msg, int playerId)
{
    Console.WriteLine($"player={playerId}, lastCmd={msg.LastCommandNumber}");
    return HookResult.Continue;
}

Server and Internal Server Hooks

Same shape, different attribute and delegate signature - APIServerNetMessageHandler has no playerId, APIServerNetMessageInternalHandler does:

[ServerNetMessageHandler]
public HookResult OnServerSound(CMsgSosStartSoundEvent msg)
{
    Console.WriteLine($"sound hash={msg.SoundeventHash}");
    return HookResult.Continue;
}
 
[ServerNetMessageInternalHandler]
public HookResult OnServerSoundInternal(CMsgSosStartSoundEvent msg, int playerId)
{
    Console.WriteLine($"player={playerId}, sound hash={msg.SoundeventHash}");
    return HookResult.Continue;
}

Register the programmatic equivalents with APIINetMessageService.HookServerMessage/APIINetMessageService.HookServerMessageInternal, same Load/Unload/Guid pattern as the client hook above.

HookResult Behavior

Net-message hooks return HookResult.Continue (allow) or HookResult.Stop (block) - in client hooks that blocks delivery to the server, in server/internal hooks it blocks delivery to clients.

Unhooking

Unhook by Guid via APIINetMessageService.Unhook, or clear all hooks for a specific net-message type:

Core.NetMessage.Unhook(hookGuid);
 
Core.NetMessage.UnhookClientMessage<CCLCMsg_Move>();
Core.NetMessage.UnhookServerMessage<CMsgSosStartSoundEvent>();
Core.NetMessage.UnhookServerMessageInternal<CMsgSosStartSoundEvent>();

See APIINetMessageService.UnhookClientMessage, APIINetMessageService.UnhookServerMessage and APIINetMessageService.UnhookServerMessageInternal. Their handler delegates are generic over T constrained to APIITypedProtobuf`1, APIINetMessage`1 and IDisposable.

Working with the Raw Payload Accessor

Generated message interfaces expose typed properties, plus Accessor (APIIProtobufAccessor) for field-based access when needed:

private HookResult OnServerSound(CMsgSosStartSoundEvent msg)
{
    uint hash = msg.Accessor.HasField("soundevent_hash")
        ? msg.Accessor.GetUInt32("soundevent_hash")
        : msg.SoundeventHash;
 
    Console.WriteLine($"sound hash={hash}");
    return HookResult.Continue;
}