Mirror/doc/Articles/Guides/Communications/NetworkBehaviourCallbacks.md

NetworkBehaviour Callbacks

See also xref:Mirror.NetworkBehaviour in the API Reference.

There are a number of events relating to network behaviours that can occur over the course of a normal multiplayer game. These include events such as the host starting up, a player joining, or a player leaving. Each of these possible events has an associated callback that you can implement in your own code to take action when the event occurs.

When you create a script which inherits from NetworkBehaviour, you can write your own implementation of what should happen when these events occur. To do this, you override the virtual methods on the NetworkBehaviour class with your own implementation of what should happen when the given event occurs.

This is a full list of virtual methods (callbacks) that you can implement on NetworkBehaviour, and where they are called

Server Only

• OnStartServer
  • called when behaviour is spawned on server
• OnStopServer
  • called when behaviour is destroyed or unspawned on server
• OnSerialize
  • called when behaviour is serialize before it is sent to client, when overriding make sure to call base.OnSerialize

Client only

• OnStartClient

  • called when behaviour is spawned on client

• OnStartAuthority

  • called when behaviour has authority when it is spawned (eg local player)
  • called when behaviour is given authority by the sever

• OnStartLocalPlayer

  • called when the behaviour is on the local player object

• OnStopAuthority

  • called when authority is taken from the object (eg local player is replaced but not destroyed)

• OnStopClient

  • called when object is destroyed on client by the ObjectDestroyMessage or ObjectHideMessage messages

Example flows

Below is some example call order for different modes

NOTE: Start is called by unity before the first frame, while normally this happens after Mirror's callbacks. But if you dont call NetworkServer.Spawn the same frame as instantiate then start may be called first

Note: OnRebuildObservers and OnSetHostVisibility is now on NetworkVisibility instead of NetworkBehaviour

Server mode

When a NetworkServer.Spawn is called (eg when new client connections and a player is created)

• OnStartServer
• OnRebuildObservers
• Start

Client mode

When local player is spawned for client

• OnStartAuthority
• OnStartClient
• OnStartLocalPlayer
• Start

Host mode

These are only called on the Player Game Objects when a client connects:

• OnStartServer
• OnRebuildObservers
• OnStartAuthority
• OnStartClient
• OnSetHostVisibility
• OnStartLocalPlayer
• Start