Mirror/doc/Guides/Authority.md

Network Authority

Servers and clients can both manage a game object’s behavior. The concept of “authority” refers to how and where a game object is managed.

Server Authority

The default state of authority in networked games using Mirror is that the Server has authority over all game objects which do not represent players. This means, for example, the server would manage control of all collectible items, moving platforms, NPCs, and any other parts of your game that players can interact with, and player game objects have authority on their owner’s client (meaning the client manages their behavior).

Client Authority

Client authority means the local client can control a networked game object. By default only the server has control over a networked object.

In practical terms, having client authority means that the client can call Command methods, and if the client disconnects, the object is automatically destroyed.

Use the NetworkIdentity.hasAuthority property in the client to find out whether a game object has local authority (also accessible on NetworkBehaviour for convenience).

Assigning authority to a client causes Mirror to call OnStartAuthority() on each NetworkBehaviour on the game object on the authority client, and sets the hasAuthority property to true. On other clients, the hasAuthority property remains false.

Player objects always have client authority. This is required for controlling movement and other player actions.

Client Authority is not to be confused with client authoritative architecture Any action must still go to the server via a Command. The client cannot modify SyncVars or affect other clients directly.

Non-Player Game Objects

There are two ways to grant client authority over non-player game objects:

1. Spawn the game object using NetworkServer.Spawn and pass the network connection of the client to take ownership.
2. Use NetworkIdentity.AssignClientAuthority with the network connection of the client to take ownership.

Additionally, there is an optional parameter for [Command] that bypasses the authority check: [Command(ignoreAuthority = true)] which allows them to be invoked without the client having authority of the object.

The example below spawns a game object and assigns authority to the client of the player that spawned it, and also shows how to assign authority on request.

[Command]
void CmdSpawn()
{
    GameObject go = Instantiate(otherPrefab, transform.position + new Vector3(0,1,0), Quaternion.identity);
    NetworkServer.Spawn(go, connectionToClient);
}

[Command]
void GrantAuthority(GameObject target)
{
    // target must have a NetworkIdentity component to be passed through a Command
    // and must already exist on both server and client
    target.GetComponent<NetworkIdentity>().AssignClientAuthority(connectionToClient);
}

Network Context Properties

The NetworkBehaviour class contains properties that allow scripts to know what the context of a networked game object is at any time.

• isServer: true if the game object is on a server and has been spawned.
• isClient: true if the game object is on a client, and was created by the server.
• isLocalPlayer: true if the game object is a player game object for this client.
• hasAuthority: true if the game object is owned by this client.

On the server, the NetworkIdentity holds the owning client in connectionToClient.

To see these properties, select the game object you want to inspect, and in the Inspector window, view the preview window for the NetworkBehaviour scripting components. You can use the value of these properties to execute code based on the context in which the script is running.