Unity Callbacks

This networking library uses Unity’s SendMessage system to notify your scripts about important network events. Any MonoBehaviour in the scene can implement these methods, and they will be called automatically when the corresponding event happens.

Callbacks are grouped below by category.

Connection Status Callbacks

These are fired in response to changes in the underlying Lidgren connection state. They are triggered by UCNetwork.HandleMessage_StatusChanged.

OnNetStatusNone() Fired when the connection status is None (not yet initialized).
OnNetStatusInitiatedConnect() Fired when the client begins attempting a connection.
OnNetStatusReceivedInitiation() Fired when the other endpoint responds to the connection initiation.
OnNetStatusRespondedAwaitingApproval() Fired when the server has received a connection request but has not yet approved or denied it.
OnNetStatusRespondedConnect() Fired when the server has approved the connection and a response has been received.
OnNetStatusConnected() Fired when the connection is fully established and ready for data.
OnNetStatusDisconnecting() Fired when a connection is in the process of disconnecting.
OnNetStatusDisconnected() Fired when a connection has been closed.

Server-Specific Callbacks

These are called only on the server side when clients join or leave.

OnClientConnected(long clientId) Fired when a client connects. The clientId is the client’s RemoteUniqueIdentifier.
OnClientDisconnected(long clientId) Fired when a client disconnects. The clientId is the client’s RemoteUniqueIdentifier.

Ownership Callbacks

These are fired on networked objects (those with a NetworkSync) when ownership changes. They are triggered by UCNetwork.AddOwnedId and UCNetwork.RemoveOwnedId.

OnGainOwnership() Fired when this machine becomes the owner of the object. Typically used to enable input, authority-driven logic, or camera follow.
OnLoseOwnership() Fired when this machine loses ownership of the object. Typically used to disable input and relinquish control.

Object Lifecycle Callbacks

These are invoked on GameObjects with a NetworkSync when they are instantiated or destroyed by the networking system.

NetworkInitialized() Fired after an object has been instantiated and its NetworkSync has been assigned a network ID. Use this for initialization logic that depends on networking.
OnDestroyNetworkObject() (optional) If implemented, can be used to clean up before a networked object is destroyed. (Default destruction is automatic.)

Custom Event Hooks

Some callbacks are reserved for optional or advanced features:

Voice Chat (stubbed) If you implement voice chat, additional callbacks may be added such as OnVoiceDataReceived(int networkId, byte[] data). These are not wired by default but can be integrated with the existing VoiceData message type.

Example Usage

Client Status Display

public class StatusUI : MonoBehaviour
{
    void OnNetStatusConnected()
    {
        Debug.Log("Connected to server!");
    }

    void OnNetStatusDisconnected()
    {
        Debug.Log("Disconnected from server.");
    }
}

Server Logging

public class ServerLogger : MonoBehaviour
{
    void OnClientConnected(long clientId)
    {
        Debug.Log("Client joined: " + clientId);
    }

    void OnClientDisconnected(long clientId)
    {
        Debug.Log("Client left: " + clientId);
    }
}

Ownership Example

public class PlayerController : MonoBehaviour
{
    bool hasControl;

    void OnGainOwnership()
    {
        hasControl = true;
        Debug.Log("Now controlling this player object.");
    }

    void OnLoseOwnership()
    {
        hasControl = false;
        Debug.Log("Lost control of this player object.");
    }
}

Summary

Connection callbacks reflect client/server connect and disconnect events.
Server callbacks notify when clients join or leave.
Ownership callbacks let you react when authority changes.
Object lifecycle callbacks run when objects are created and initialized.
These methods are automatically invoked if present on your scripts.