[Command]

[Command] attribute is used when a client needs to call a function on the server. It allows a client to request the server to execute a function.

Key Features

• Can only be called from the client to the server.
• Executed on the server.
• The function name must begin with the Cmd prefix.
• Automatically includes the connection information of the client that called the function.

Use Examples

Basic Use

public class PlayerController : NetworkBehaviour
{
    [Client]
    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
        {
            CmdRequestJump();
        }
    }

    [Command]
    private void CmdRequestJump()
    {
        // Jump logic executed on the server
        // Physics processing, position changes, etc.
    }
}

Passing Parameters

public class PlayerCombat : NetworkBehaviour
{
    [Client]
    private void OnFireButtonPressed(Vector3 targetPosition)
    {
        CmdFireWeapon(targetPosition);
    }

    [Command]
    private void CmdFireWeapon(Vector3 targetPosition)
    {
        // Shooting logic executed on the server
        // Bullet creation, collision handling, etc.
    }
}

Authentication Check

public class PlayerInventory : NetworkBehaviour
{
    [Command]
    private void CmdUseItem(int itemId)
    {
        // Check if the client owns the item
        if (!isOwned)
            return;

        // Check if the item can be used
        if (!HasItem(itemId))
            return;

        // Item use logic
        UseItemOnServer(itemId);
    }
}

note

1. The [Command] attribute is used to safely process client requests on the server.
2. The function name must always start with Cmd to ensure it is correctly recognized as a command.
3. It is primarily used to pass player actions such as input handling, item usage, or attacks from the client to the server. :::