Version: 1.1.0

ClientRpc

Servers can invoke a ClientRpc to execute on all clients.

Declaring a ClientRpc

You can declare a ClientRpc by marking a method with [ClientRpc] attribute and including the ClientRpc suffix in the method name.

[ClientRpc]
void PongClientRpc(int somenumber, string sometext) { /* ... */ }

Invoking a ClientRpc

You can invoke a ClientRpc by making a direct function call with parameters:

void Update()
{
    if (Input.GetKeyDown(KeyCode.P))
    {
        PongClientRpc(Time.frameCount, "hello, world"); // Server -> Client
    }
}

You must mark client RPC methods with the [ClientRpc] attribute and use the ClientRpc method suffix; failing to do so results in an error message.

// Error: Invalid, missing 'ClientRpc' suffix in the method name
[ClientRpc]
void Pong(int somenumber, string sometext) { /* ... */ }

// Error: Invalid, missing [ClientRpc] attribute on the method
void PongClientRpc(int somenumber, string sometext) { /* ... */ }

The [ClientRpc] attribute and matching ...ClientRpc suffix in the method name are there to ensure RPC call sites know when they're executing an RPC. The client RPC replicates and executes client-side, without jumping into the original RPC method declaration to find out if it's an RPC.

Pong(somenumber, sometext); // Is this an RPC call?

PongRpc(somenumber, sometext); // Is this a ServerRpc call or ClientRpc call?

PongClientRpc(somenumber, sometext); // This is clearly a ClientRpc call

To Send to One Client, use ClientRpcSendParameters

The following code provides an example of using ClientRpcSendParameters, which sends a ClientRpc to a specific client connections. The default Netcode for GameObjects's behavior is to broadcast to every single client.

private void DoSomethingServerSide(int clientId)
    {
        // If isn't the Server/Host then we should early return here!
        if (!IsServer) return;


        // NOTE! In case you know a list of ClientId's ahead of time, that does not need change,
        // Then please consider caching this (as a member variable), to avoid Allocating Memory every time you run this function
        ClientRpcParams clientRpcParams = new ClientRpcParams
        {
            Send = new ClientRpcSendParams
            {
                TargetClientIds = new ulong[]{clientId}
            }
        };

        // Let's imagine that you need to compute a Random integer and want to send that to a client
        const int maxValue = 4;
        int randomInteger = Random.Range(0, maxValue);
        DoSomethingClientRpc(randomInteger, clientRpcParams);
    }

    [ClientRpc]
    private void DoSomethingClientRpc(int randomInteger, ClientRpcParams clientRpcParams = default)
    {
        if (IsOwner) return;

        // Run your client-side logic here!!
        Debug.LogFormat("GameObject: {0} has received a randomInteger with value: {1}", gameObject.name, randomInteger);
    }