Netcode for GameObjects

https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/
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Netcode for GameObjects is a high-level networking library built for Unity that abstracts networking...
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### OnSetup()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTest.html

Called before creating and starting the server and clients. Override to perform setup logic before the test's network objects are created.

```APIDOC
## OnSetup()

### Description
Called before creating and starting the server and clients. Note: For AllTests and PerTest mode integration tests, if you want to have access to the server or client NetworkManagers then override OnServerAndClientsCreated().

### Declaration
```csharp
protected virtual IEnumerator OnSetup()
```

### Returns
| Type | Description |
| --- | --- |
| IEnumerator | IEnumerator |
```

--------------------------------

### Start(bool, NetworkManager, NetworkManager[], BeforeClientStartCallback, bool)

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTestHelpers.html

Starts NetworkManager instances created by the Create method. It starts the server and optionally the clients, with a callback invoked before clients start.

```APIDOC
## Start(bool, NetworkManager, NetworkManager[], BeforeClientStartCallback, bool)

### Description
Starts NetworkManager instances created by the Create method.

### Method
Start

### Signature
public static bool Start(bool host, NetworkManager server, NetworkManager[] clients, NetcodeIntegrationTestHelpers.BeforeClientStartCallback callback = null, bool startServer = true)

### Parameters
- **host** (bool) - Whether or not to create a Host instead of Server.
- **server** (NetworkManager) - The Server NetworkManager.
- **clients** (NetworkManager[]) - The Clients NetworkManager.
- **callback** (BeforeClientStartCallback) - Called immediately after server is started and before client(s) are started. Optional.
- **startServer** (bool) - true to start it, false to not start it. Default is true.

### Returns
- **bool** - true if all instances started successfully, false otherwise.
```

--------------------------------

### Server-side connection approval example (C#)

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/basics/connection-approval.html

Sets up the connection approval callback and starts a host. The callback receives the client ID and payload, and sets approval fields such as Approved, CreatePlayerObject, PlayerPrefabHash, Position, Rotation, Reason, and Pending.

```csharp
using Unity.Netcode;

private void Setup()
{
    NetworkManager.Singleton.ConnectionApprovalCallback = ApprovalCheck;
    NetworkManager.Singleton.StartHost();
}

private void ApprovalCheck(NetworkManager.ConnectionApprovalRequest request, NetworkManager.ConnectionApprovalResponse response)
{
    // The client identifier to be authenticated
    var clientId = request.ClientNetworkId;

    // Additional connection data defined by user code
    var connectionData = request.Payload;

    // Your approval logic determines the following values
    response.Approved = true;
    response.CreatePlayerObject = true;

    // The Prefab hash value of the NetworkPrefab, if null the default NetworkManager player Prefab is used
    response.PlayerPrefabHash = null;

    // Position to spawn the player object (if null it uses default of Vector3.zero)
    response.Position = Vector3.zero;

    // Rotation to spawn the player object (if null it uses the default of Quaternion.identity)
    response.Rotation = Quaternion.identity;

    // If response.Approved is false, you can provide a message that explains the reason why via ConnectionApprovalResponse.Reason
    // On the client-side, NetworkManager.DisconnectReason will be populated with this message via DisconnectReasonMessage
    response.Reason = "Some reason for not approving the client";

    // If additional approval steps are needed, set this to true until the additional steps are complete
    // once it transitions from true to false the connection approval response will be processed.
    response.Pending = false;
}
```

--------------------------------

### Start client (Windows command line)

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/tutorials/command-line-helper.html

Command to start the client instance of the HelloWorld executable. Replace the placeholder text within angled brackets with the actual path to the project.

```dos
<path to project>\HelloWorld.exe -mode client

```

--------------------------------

### Start as a host with NetworkManager.Singleton.StartHost()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/components/core/networkmanager.html

Starts the NetworkManager as a host, which is both a server and a client. Can send RPCs to itself and start sending messages before another client connects. Only works with client-server topology.

```csharp
NetworkManager.Singleton.StartHost();
```

--------------------------------

### OnStart()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.TimeoutFrameCountHelper.html

Virtual method to override in order to setup a derived class when started. Overrides TimeoutHelper.OnStart().

```APIDOC
## OnStart()

### Description
Virtual method to override in order to setup a derived class when started.

### Method
protected override void OnStart()

### Overrides
[TimeoutHelper.OnStart()](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.TimeoutHelper.html#Unity_Netcode_TestHelpers_Runtime_TimeoutHelper_OnStart)

```

--------------------------------

### StartServer()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkManager.html

Starts a server.

```APIDOC
## StartServer()

### Description
Starts a server.

### Method
StartServer()

### Returns
- **bool** - returns true if NetworkManager started in server mode successfully; otherwise false

### Declaration
```csharp
public bool StartServer()
```
```

--------------------------------

### Start server (Windows command line)

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/tutorials/command-line-helper.html

Command to start the server instance of the HelloWorld executable. Replace the placeholder text within angled brackets with the actual path to the project.

```dos
<Path to Project>\HelloWorld.exe -mode server

```

--------------------------------

### Start as a server with NetworkManager.Singleton.StartServer()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/components/core/networkmanager.html

Starts the NetworkManager as a server. A server cannot act as a local client and will not send messages until at least one other client is connected. Only works with client-server topology.

```csharp
NetworkManager.Singleton.StartServer();
```

--------------------------------

### Start()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.TimeoutHelper.html

Starts the timeout helper.

```APIDOC
## Start()

### Description
Invoke to start.

### Declaration
```csharp
public void Start()
```
```

--------------------------------

### Start server, host, or client with NetworkManager.Singleton

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/troubleshooting/troubleshooting.html

These three lines show how to start a server, host, or client using NetworkManager.Singleton. If a NullReferenceException is thrown, ensure the NetworkManager component is added to a game object in the scene.

```csharp
NetworkManager.Singleton.StartServer()
NetworkManager.Singleton.StartHost()
NetworkManager.Singleton.StartClient()
```

--------------------------------

### Example of single-line command with log files

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/tutorials/command-line-helper.html

Example command showing how to run both server and client with log files on a single command line.

```dos
C:\Users\sarao>HelloWorld\Build\HelloWorld.exe -logfile log-server.txt -mode server & HelloWorld\Build\HelloWorld.exe -logfile log-client.txt -mode client

```

--------------------------------

### StartHost()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkManager.html

Starts a Host.

```APIDOC
## StartHost()

### Description
Starts a Host.

### Method
StartHost()

### Returns
- **bool** - (true/false) returns true if NetworkManager started in host mode successfully.

### Declaration
```csharp
public bool StartHost()
```
```

--------------------------------

### StartClient()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkManager.html

Starts a client.

```APIDOC
## StartClient()

### Description
Starts a client.

### Method
StartClient()

### Returns
- **bool** - (true/false) returns true if NetworkManager started in client mode successfully.

### Declaration
```csharp
public bool StartClient()
```
```

--------------------------------

### Start as a client with NetworkManager.Singleton.StartClient()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/components/core/networkmanager.html

Starts the NetworkManager as a client. This is the most general option; it connects to a server or host (client-server topology) or to a distributed authority session. Under distributed authority, the first client to join becomes the session owner.

```csharp
NetworkManager.Singleton.StartClient();
```

--------------------------------

### UnityTransport.StartServer()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.Transports.UTP.UnityTransport.html

Starts listening for incoming clients. Returns true if the server was started, false if it failed. This method overrides NetworkTransport.StartServer().

```APIDOC
## StartServer()

### Description
Starts to listening for incoming clients. Note: When this method returns false it could mean:
- You are trying to start a client that is already started
- It failed during the initial port binding when attempting to begin to connect

### Declaration
```csharp
public override bool StartServer()
```

### Returns
| Type | Description |
| --- | --- |
| [bool](https://learn.microsoft.com/dotnet/api/system.boolean) | true if the server was started and false if it failed to start the server |

### Overrides
[NetworkTransport.StartServer()](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkTransport.html#Unity_Netcode_NetworkTransport_StartServer)

```

--------------------------------

### Initialize components in Start and OnNetworkSpawn

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/components/core/networkbehaviour.html

Use this pattern to ensure components are assigned for both dynamically spawned and in-scene placed NetworkObjects. The Initialize method is called from both Start and OnNetworkSpawn to handle the different invocation order.

```csharp
public class MyNetworkBehaviour : NetworkBehaviour
{
    private MeshRenderer m_MeshRenderer;
    private void Start()
    {
        Initialize();
    }

    private void Initialize()
    {
        if (m_MeshRenderer == null)
        {
            m_MeshRenderer = FindObjectOfType<MeshRenderer>();
        }
    }

    public override void OnNetworkSpawn()
    {
        Initialize();
        // Do things with m_MeshRenderer

        base.OnNetworkSpawn();
    }
}
```

--------------------------------

### GetTimeElapsed()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.TimeoutHelper.html

Gets the time that has passed since the helper was started.

```APIDOC
## GetTimeElapsed()

### Description
Gets the time that has passed since started.

### Declaration
```csharp
public float GetTimeElapsed()
```

### Returns
| Type | Description |
| --- | --- |
| float | float as the time that has passed. |
```

--------------------------------

### NetworkTime.TickWithPartial

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkTime.html

Gets the tick, including partial tick value passed since it started.

```APIDOC
## NetworkTime.TickWithPartial

### Description
Gets the tick, including partial tick value passed since it started.

### Declaration
```csharp
public double TickWithPartial { get; }
```

### Property Value
| Type | Description |
| --- | --- |
| double | The tick value including partial ticks. |
```

--------------------------------

### StartServer()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.Transports.SinglePlayer.SinglePlayerTransport.html

Starts listening for incoming clients. For local single player sessions, use StartHost() instead.

```APIDOC
## StartServer()

### Description
Starts listening for incoming clients. For local single player sessions, use StartHost() instead.

### Method
StartServer

### Declaration
```csharp
public override bool StartServer()
```

### Returns
| Type | Description |
| --- | --- |
| bool | Returns success or failure |

### Overrides
[NetworkTransport.StartServer()](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkTransport.html#Unity_Netcode_NetworkTransport_StartServer)

### Remarks
Always use StartHost() when hosting a local single player session.
```

--------------------------------

### OnStart()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.TimeoutHelper.html

Virtual method called when the helper starts. Override to set up derived classes.

```APIDOC
## OnStart()

### Description
Virtual method to override in order to setup a derived class when started.

### Declaration
```csharp
protected virtual void OnStart()
```
```

--------------------------------

### CustomNamedMessageHandler example for named messages

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/advanced-topics/message-system/custom-messages.html

A NetworkBehaviour that registers a named message handler on spawn, sends a Guid to the server from clients, and broadcasts to all clients from the server. It uses FastBufferWriter and ForceNetworkSerializeByMemcpy<Guid> for the payload. Note that SendNamedMessageToAll is server-only and throws on clients.

```csharp
using System;
using UnityEngine;
using Unity.Collections;
using Unity.Netcode;
public class CustomNamedMessageHandler : NetworkBehaviour
{
    [Tooltip("The name identifier used for this custom message handler.")]
    public string MessageName = "MyCustomNamedMessage";

    /// <summary>
    /// For most cases, you want to register once your NetworkBehaviour's
    /// NetworkObject (typically in-scene placed) is spawned.
    /// </summary>
    public override void OnNetworkSpawn()
    {
        // Both the server-host and client(s) register the custom named message.
        NetworkManager.CustomMessagingManager.RegisterNamedMessageHandler(MessageName, ReceiveMessage);

        if (IsServer)
        {
            // Server broadcasts to all clients when a new client connects (just for example purposes)
            NetworkManager.OnClientConnectedCallback += OnClientConnectedCallback;
        }
        else
        {
            // Clients send a unique Guid to the server
            SendMessage(Guid.NewGuid());
        }
    }

    private void OnClientConnectedCallback(ulong obj)
    {
        SendMessage(Guid.NewGuid());
    }

    public override void OnNetworkDespawn()
    {
        // De-register when the associated NetworkObject is despawned.
        NetworkManager.CustomMessagingManager.UnregisterNamedMessageHandler(MessageName);
        // Whether server or not, unregister this.
        NetworkManager.OnClientDisconnectCallback -= OnClientConnectedCallback;
    }

    /// <summary>
    /// Invoked when a custom message of type <see cref="MessageName"/>
    /// </summary>
    private void ReceiveMessage(ulong senderId, FastBufferReader messagePayload)
    {
        var receivedMessageContent = new ForceNetworkSerializeByMemcpy<Guid>(new Guid());
        messagePayload.ReadValueSafe(out receivedMessageContent);
        if (IsServer)
        {
            Debug.Log($"Sever received GUID ({receivedMessageContent.Value}) from client ({senderId})");
        }
        else
        {
            Debug.Log($"Client received GUID ({receivedMessageContent.Value}) from the server.");
        }
    }

    /// <summary>
    /// Invoke this with a Guid by a client or server-host to send a
    /// custom named message.
    /// </summary>
    public void SendMessage(Guid inGameIdentifier)
    {
        var messageContent = new ForceNetworkSerializeByMemcpy<Guid>(inGameIdentifier);
        var writer = new FastBufferWriter(1100, Allocator.Temp);
        var customMessagingManager = NetworkManager.CustomMessagingManager;
        using (writer)
        {
            writer.WriteValueSafe(messageContent);
            if (IsServer)
            {
                // This is a server-only method that will broadcast the named message.
                // Caution: Invoking this method on a client will throw an exception!
                customMessagingManager.SendNamedMessageToAll(MessageName, writer);
            }
            else
            {
                // This is a client or server method that sends a named message to one target destination
                // (client to server or server to client)
                customMessagingManager.SendNamedMessage(MessageName, NetworkManager.ServerClientId, writer);
            }
        }
    }
}
```

--------------------------------

### Replace SyncList with NetworkList - Netcode example

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/migratingfromUNet.html

Shows the Netcode replacement using NetworkList<int> and its OnListChanged event. Subscribe in Awake or Start.

```csharp
NetworkList<int> m_ints = new NetworkList<int>();

// Call this is in Awake or Start to subscribe to changes of the NetworkList.
void ListenChanges()
{
    m_ints.OnListChanged += OnIntChanged;
}

// The NetworkListEvent has information about the operation and index of the change.
void OnIntChanged(NetworkListEvent<int> changeEvent)
{

}

```

--------------------------------

### SpawnNetworkObject(Guid)

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetworkManagerHelper.html

Spawns the NetworkObject so that RPCs can flow. Takes a Guid identifier to reference the game object.

```APIDOC
## SpawnNetworkObject(Guid)

### Description
Spawns the NetworkObject so that RPCs can flow. Takes a Guid identifier to reference the game object.

### Method
SpawnNetworkObject

### Signature
```csharp
public static void SpawnNetworkObject(Guid gameObjectIdentifier)
```

### Parameters
- **gameObjectIdentifier** (Guid) - Required - ID returned to reference the game object.

### Returns
void
```

--------------------------------

### RPC Target Override Examples

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/advanced-topics/message-system/rpc-params.html

Demonstrates how to use RpcTarget to override the destination of an RPC at runtime, with examples of valid and invalid usage.

```APIDOC
## RPC Target Override Examples

### Description
Shows how to override the destination of an RPC using RpcTarget, and the conditions under which it is allowed.

### Method
RPC

### Parameters
#### Method Parameters
- **rpcParams** (RpcParams) - Optional - Runtime parameters for the RPC.

### Request Example
```csharp
[Rpc(SendTo.Server)]
void ServerRpc(RpcParams rpcParams = default) { /* ... */ }

[Rpc(SendTo.SpecifiedInParams)]
void RuntimeSpecifiedRpc(RpcParams rpcParams = default) { /* ... */ }

[Rpc(SendTo.Server, AllowTargetOverride = true)]
void OverridableServerRpc(RpcParams rpcParams = default) { /* ... */ }

// Throws an exception: SendTo.Server cannot be overriden for ServerRpc
ServerRpc(RpcTarget.NotServer);
ServerRpc(RpcTarget.Single(someClientId, RpcTargetUse.Temp));

// Works
RuntimeSpecifiedRpc(RpcTarget.NotServer);
RuntimeSpecifiedRpc(RpcTarget.Single(someClientId, RpcTargetUse.Temp));

// Works
OverridableServerRpc(RpcTarget.NotServer);
OverridableServerRpc(RpcTarget.Single(someClientId, RpcTargetUse.Temp));
```

### Response
No response body.
```

--------------------------------

### Get Network FixedTime in Update

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/advanced-topics/networktime-ticks.html

Use this to get the time during the current Update and the time during the previous network tick, similar to FixedUpdate.

```csharp
public void Update()
{
    double time = NetworkManager.Singleton.LocalTime.Time; // time during this Update
    double fixedTime = NetworkManager.Singleton.LocalTime.FixedTime; // time during the previous network tick
}
```

--------------------------------

### m_SetupIsACoroutine

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTest.html

Protected virtual property that indicates whether SetUp should be treated as a coroutine. If false, OnInlineSetUp is called instead of OnSetUp for performance.

```APIDOC
## m_SetupIsACoroutine

### Description
Protected virtual property that indicates whether SetUp should be treated as a coroutine. If false, OnInlineSetUp is called instead of OnSetUp for performance.

### Declaration
```csharp
protected virtual bool m_SetupIsACoroutine { get; }
```

### Property Value
| Type | Description |
| --- | --- |
| bool | |

```

--------------------------------

### NullReferenceException when starting server/host/client

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/troubleshooting/troubleshooting.html

This exception is thrown when trying to start a server, host, or client without the NetworkManager component added to a game object in the scene.

```csharp
NullReferenceException: Object reference not set to an instance of an object
```

--------------------------------

### Start client on macOS

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/tutorials/command-line-helper.html

Launches the HelloWorld client from the macOS Terminal. Replace <Path to Project> and <Project Name> with actual values.

```shell
<Path to Project>/HelloWorld.app/Contents/MacOS/<Project Name> -mode client -logfile -
```

--------------------------------

### Example struct with Serialize method

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/advanced-topics/fastbufferwriter-fastbufferreader.html

Defines a struct with a Serialize method that takes a FastBufferWriter. This is the base example used to illustrate different serialization approaches.

```csharp
struct ExampleStruct
{
    private float f;
    private bool b;
    private int i;

    void Serialize(FastBufferWriter writer);
}
```

--------------------------------

### Start server on macOS

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/tutorials/command-line-helper.html

Launches the HelloWorld server from the macOS Terminal. Replace <Path to Project> and <Project Name> with actual values.

```shell
<Path to Project>/HelloWorld.app/Contents/MacOS/<Project Name> -mode server -logfile -
```

--------------------------------

### ChangeOwnershipBehaviour example

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/components/core/networkobject-ownership.html

Complete example of a NetworkBehaviour that changes ownership and handles ownership permission failures. It subscribes to OnOwnershipPermissionsFailure, overrides OnOwnershipChanged, and includes a TakeOwnership method.

```csharp
/*
* When the NetworkObject's permissions includes the OwnershipPermissions.Transferrable flag.
*/
public class ChangeOwnershipBehaviour : NetworkBehaviour
{
    public override void OnNetworkSpawn()
    {
      NetworkObject.OnOwnershipPermissionsFailure += OnOwnershipPermissionsFailure;
      base.OnNetworkSpawn();
    }

    public void TakeOwnership()
    {
        if (!IsOwner) {
            NetworkObject.ChangeOwnership(NetworkManager.LocalClientId);
        }
    }

    // Override this method on the NetworkBehaviour to detect ownership changes
    protected override void OnOwnershipChanged(ulong previous, ulong current)
    {
        if (IsOwner)
        {
            // If this is invoked, then the ownership change succeeded!
        }
        base.OnOwnershipChanged(previous, current);
    }

    private void OnOwnershipPermissionsFailure(NetworkObject.OwnershipPermissionsFailureStatus ownershipPermissionsFailureStatus)
    {
        // If this is invoked then the ownership change failed.
    }

    public override void OnNetworkDespawn()
    {
        NetworkObject.OnOwnershipPermissionsFailure += OnOwnershipPermissionsFailure;
        base.OnNetworkDespawn();
    }
}
```

--------------------------------

### Get network prefab override and spawn

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/basics/object-spawning.html

Use NetworkManager.GetNetworkprefabOverride to get the prefab override, instantiate it, and spawn its NetworkObject. This gives you full control over the override selection.

```csharp
var instance = Instantiate(NetworkManager.GetNetworkprefabOverride(myprefab));
var instanceNetworkObject = instance.GetComponent<NetworkObject>();
instanceNetworkObject.Spawn();
```

--------------------------------

### StartOneClient(NetworkManager)

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTestHelpers.html

Starts one single client and makes sure to register the required hooks and handlers. This method should not be called directly; use CreateAndStartNewClient() instead.

```APIDOC
## StartOneClient(NetworkManager)

### Description
Starts one single client and makes sure to register the required hooks and handlers.

### Method
StartOneClient

### Signature
public static void StartOneClient(NetworkManager clientToStart)

### Parameters
- **clientToStart** (NetworkManager) - The NetworkManager instance to start.

### Remarks
Do not call this function directly. Use CreateAndStartNewClient() instead.
```

--------------------------------

### SetUp()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTest.html

A method decorated with the UnityEngine.TestTools.UnitySetUpAttribute that is invoked once per NUnit.Framework.TestFixtureAttribute or just once if none. It is used to set up the test environment.

```APIDOC
## SetUp()

### Description
A method decorated with the UnityEngine.TestTools.UnitySetUpAttribute that is invoked once per NUnit.Framework.TestFixtureAttribute or just once if none. It is used to set up the test environment.

### Method
SetUp

### Parameters
None

### Returns
IEnumerator
```

--------------------------------

### CanStartServerAndClients()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTest.html

Override this method and return false in order to be able to manually control when the server and clients are started. Returns a boolean indicating whether the server and clients can start.

```APIDOC
## CanStartServerAndClients()

### Description
Override this method and return false in order to be able to manually control when the server and clients are started.

### Method
CanStartServerAndClients

### Signature
protected virtual bool CanStartServerAndClients()

### Returns
- **bool** - true or false
```

--------------------------------

### OnOneTimeSetup()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTest.html

Override this method to do any one time setup configurations.

```APIDOC
## OnOneTimeSetup()

### Description
Override this method to do any one time setup configurations.

### Declaration
```csharp
protected virtual void OnOneTimeSetup()
```

```

--------------------------------

### Netcode ConnectionApproval server-only example

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/migratingfromUNet.html

Shows the replacement using ConnectionApprovalCallback. It sets up the callback and defines the approval logic, including creating a player object and using a prefab hash. The callback approves or denies the connection.

```csharp
using Unity.Netcode;

private void Setup()
{
    NetworkManager.Singleton.ConnectionApprovalCallback += ApprovalCheck;
    NetworkManager.Singleton.StartHost();
}

private void ApprovalCheck(byte[] connectionData, ulong clientId, NetworkManager.ConnectionApprovedDelegate callback)
{
    //Your logic here
    bool approve = true;
    bool createPlayerObject = true;

    // The Prefab hash. Use null to use the default player prefab
    // If using this hash, replace "MyPrefabHashGenerator" with the name of a Prefab added to the NetworkPrefabs field of your NetworkManager object in the scene
    ulong? prefabHash = NetworkpawnManager.GetPrefabHashFromGenerator("MyPrefabHashGenerator");

    //If approve is true, the connection gets added. If it's false. The client gets disconnected
    callback(createPlayerObject, prefabHash, approve, positionToSpawnAt, rotationToSpawnWith);
}
```

--------------------------------

### Unnamed Message Example

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/advanced-topics/message-system/custom-messages.html

Example code showing how to send an unnamed message using CustomMessagingManager and how to create a templated handler class for receiving and processing unnamed messages.

```APIDOC
## Unnamed Message Example

### Description
This example demonstrates how to send an unnamed message using `CustomMessagingManager` and how to create a templated `NetworkBehaviour` class to handle different data types for unnamed messages.

### Code
```csharp
// Write our string message
writer.WriteValueSafe(dataToSend);
if (IsServer)
{
    // This is a server-only method that will broadcast the unnamed message.
    // Caution: Invoking this method on a client will throw an exception!
    customMessagingManager.SendUnnamedMessageToAll(writer);
}
else
{
    // This method can be used by a client or server (client to server or server to client)
    customMessagingManager.SendUnnamedMessage(NetworkManager.ServerClientId, writer);
}
```

### CustomUnnamedMessageHandler<T> Class

A templated class to handle sending different data types per unique unnamed message type/child derived class.

#### Methods

- `protected virtual byte MessageType()` - Returns the default unnamed message type (0). Override to define a unique message type identifier.
- `public override void OnNetworkSpawn()` - Subscribes to the `OnUnnamedMessage` event when the NetworkBehaviour's NetworkObject is spawned.
- `public override void OnNetworkDespawn()` - Unsubscribes from the `OnUnnamedMessage` event when the NetworkObject is despawned.
- `protected virtual void OnReceivedUnnamedMessage(ulong clientId, FastBufferReader reader)` - Override to handle reading a unique message type.
- `private void ReceiveMessage(ulong clientId, FastBufferReader reader)` - Reads the message type value and calls `OnReceivedUnnamedMessage` if it matches the expected type.
- `public virtual void SendUnnamedMessage(T dataToSend)` - Default does nothing; override to implement sending logic.

#### Usage Notes
- Both server-host and clients subscribe to the `OnUnnamedMessage` event.
- The message type identifier is written first when sending, and read first when receiving.

```

--------------------------------

### Get PlayerObject for a specific client on server

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/components/core/playerobjects.html

Use this on the server-side to retrieve the PlayerObject instance for a given client ID. Pass NetworkManager.Singleton.LocalClientId as clientId to get your own player object.

```csharp
NetworkManager.Singleton.ConnectedClients[clientId].PlayerObject;

```

--------------------------------

### StartClient()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.Transports.SinglePlayer.SinglePlayerTransport.html

Connects client to the server. This method always returns false for SinglePlayerTransport. Use StartServer() instead.

```APIDOC
## StartClient()

### Description
Connects client to the server. This method always returns false for SinglePlayerTransport. Use StartServer() instead.

### Method
StartClient

### Declaration
```csharp
public override bool StartClient()
```

### Returns
| Type | Description |
| --- | --- |
| bool | Returns success or failure |

### Overrides
[NetworkTransport.StartClient()](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkTransport.html#Unity_Netcode_NetworkTransport_StartClient)

### Remarks
This will always return false for SinglePlayerTransport. Always use StartServer().
```

--------------------------------

### NetworkCommandLine.cs - command-line helper for launching server/host/client

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/tutorials/command-line-helper.html

This script reads command-line arguments to start the NetworkManager as a server, host, or client. It ignores the script in the Editor and parses arguments like '-mode server' to determine the startup mode.

```csharp
using System.Collections.Generic;
using Unity.Netcode;
using UnityEngine;

public class NetworkCommandLine : MonoBehaviour
{
   private NetworkManager netManager;

   void Start()
   {
       netManager = GetComponentInParent<NetworkManager>();

       if (Application.isEditor) return;

       var args = GetCommandlineArgs();

       if (args.TryGetValue("-mode", out string mode))
       {
           switch (mode)
           {
               case "server":
                   netManager.StartServer();
                   break;
               case "host":
                   netManager.StartHost();
                   break;
               case "client":

                   netManager.StartClient();
                   break;
           }
       }
   }

   private Dictionary<string, string> GetCommandlineArgs()
   {
       Dictionary<string, string> argDictionary = new Dictionary<string, string>();

       var args = System.Environment.GetCommandLineArgs();

       for (int i = 0; i < args.Length; ++i)
       {
           var arg = args[i].ToLower();
           if (arg.StartsWith("-"))
           {
               var value = i < args.Length - 1 ? args[i + 1].ToLower() : null;
               value = (value?.StartsWith("-") ?? false) ? null : value;

               argDictionary.Add(arg, value);
           }
       }
       return argDictionary;
   }
}
```

--------------------------------

### CreateAndStartNewClient()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTest.html

This will create, start, and connect a new client while in the middle of an integration test.

```APIDOC
## CreateAndStartNewClient()

### Description
This will create, start, and connect a new client while in the middle of an integration test.

### Declaration
```csharp
protected IEnumerator CreateAndStartNewClient()
```

### Returns
| Type | Description |
| --- | --- |
| IEnumerator | An IEnumerator to be used in a coroutine for asynchronous execution. |

```

--------------------------------

### CreateAndStartNewClientWithTimeTravel()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.TestHelpers.Runtime.NetcodeIntegrationTest.html

Creates a client and waits for it to connect via simulated frames.

```APIDOC
## CreateAndStartNewClientWithTimeTravel()

### Description
Creates a client and waits for it to connect via simulated frames.

### Method
CreateAndStartNewClientWithTimeTravel

### Parameters
None.

```

--------------------------------

### HelloWorldManager.cs full script

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/manual/tutorials/get-started-with-ngo.html

Complete HelloWorldManager.cs script that adds a runtime UI to start a Host, Client, or Server and to submit position changes. It uses a private NetworkManager reference obtained via GetComponent in Awake. The UI shows status labels and a Move/Request Position Change button.

```csharp
using Unity.Netcode;
using UnityEngine;

namespace HelloWorld
{
    /// <summary>
    /// Add this component to the same GameObject as
    /// the NetworkManager component.
    /// </summary>
    public class HelloWorldManager : MonoBehaviour
    {
        private NetworkManager m_NetworkManager;

        private void Awake()
        {
            m_NetworkManager = GetComponent<NetworkManager>();
        }

        private void OnGUI()
        {
            GUILayout.BeginArea(new Rect(10, 10, 300, 300));
            if (!m_NetworkManager.IsClient && !m_NetworkManager.IsServer)
            {
                StartButtons();
            }
            else
            {
                StatusLabels();

                SubmitNewPosition();
            }

            GUILayout.EndArea();
        }

        private void StartButtons()
        {
            if (GUILayout.Button("Host")) m_NetworkManager.StartHost();
            if (GUILayout.Button("Client")) m_NetworkManager.StartClient();
            if (GUILayout.Button("Server")) m_NetworkManager.StartServer();
        }

        private void StatusLabels()
        {
            var mode = m_NetworkManager.IsHost ?
                "Host" : m_NetworkManager.IsServer ? "Server" : "Client";

            GUILayout.Label("Transport: " +
                m_NetworkManager.NetworkConfig.NetworkTransport.GetType().Name);
            GUILayout.Label("Mode: " + mode);
        }

        private void SubmitNewPosition()
        {
            if (GUILayout.Button(m_NetworkManager.IsServer ? "Move" : "Request Position Change"))
            {
                if (m_NetworkManager.IsServer && !m_NetworkManager.IsClient)
                {
                    foreach (ulong uid in m_NetworkManager.ConnectedClientsIds)
                        m_NetworkManager.SpawnManager.GetPlayerNetworkObject(uid).GetComponent<HelloWorldPlayer>().Move();
                }
                else
                {
                    var playerObject = m_NetworkManager.SpawnManager.GetLocalPlayerObject();
                    var player = playerObject.GetComponent<HelloWorldPlayer>();
                    player.Move();
                }
            }
        }
    }
}
```

--------------------------------

### OnInitialize()

Source: https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.AnticipatedNetworkVariable-1.html

Initializes the network variable, setting up initial values and registering with the anticipation system.

```APIDOC
## OnInitialize()

### Description
Initializes the network variable, setting up initial values and registering with the anticipation system.

### Declaration
```csharp
public override void OnInitialize()
```

### Overrides
[NetworkVariableBase.OnInitialize()](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@2.11/api/Unity.Netcode.NetworkVariableBase.html#Unity_Netcode_NetworkVariableBase_OnInitialize)
```
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