Last Update: 2023-07-06

Network

Network nodes handle the synchronization of game state between server and clients in Don't Starve Together's multiplayer environment.

Overview

Network nodes enable multiplayer functionality by serializing and deserializing game state data, handling replication of entities and their properties, and managing client-server communication.

Network Components

NetVars (Network Variables)

NetVars are variables that are automatically synchronized between server and clients:

-- Defining network variables
self.isopen = net_bool(self.inst.GUID, "chest.isopen", "isopendirty")
self.health = net_float(self.inst.GUID, "health.current", "healthdirty")
self.playername = net_string(self.inst.GUID, "player.name", "namedirty")

Common NetVar types:

• net_bool: Boolean values
• net_byte: Small integer values (0-255)
• net_shortint: Short integer values
• net_int: Integer values
• net_float: Floating point values
• net_string: String values
• net_entity: Entity references
• net_hash: Hash values
• net_smallbyte: Very small integer values (0-15)

Listening for Network Events

-- On server side
self.isopen:set(true)

-- On client side
self.inst:ListenForEvent("isopendirty", function()
    local isopen = self.isopen:value()
    -- Update client-side presentation based on isopen value
end)

Replication

Replication is the process of synchronizing entity state between server and clients:

-- Common pattern for component replication
local function OnHealthDelta(inst)
    if not inst.components.health:IsDead() then
        inst.AnimState:SetPercent("hit", 1 - inst.components.health:GetPercent())
    end
end

local function OnIsOpen(inst)
    if inst.isopen:value() then
        inst.AnimState:PlayAnimation("open")
    else
        inst.AnimState:PlayAnimation("close")
    end
end

-- Create client-side representation
local function ClientInit(inst)
    inst:ListenForEvent("healthdirty", OnHealthDelta)
    inst:ListenForEvent("isopendirty", OnIsOpen)
end

-- Create server-side representation
local function MasterInit(inst)
    -- Server-side initialization
end

-- Common initialization
local function SharedInit(inst)
    -- Shared initialization
end

return function(inst)
    SharedInit(inst)
    
    if TheWorld.ismastersim then
        MasterInit(inst)
    else
        ClientInit(inst)
    end
end

RPC (Remote Procedure Calls)

RPCs allow executing functions remotely:

-- Define an RPC
AddClientModRPCHandler("MyMod", "DoSomething", function(player, arg1, arg2)
    -- Handle the RPC on receiving side
end)

-- Send an RPC
SendModRPCToServer("MyMod", "DoSomething", arg1, arg2)

Network Tags

Some special tags affect network behavior:

• _master: Entity exists on server
• _replica: Entity's client replica
• networker: Entity handles network communication

Master Simulation

The server is responsible for running the master simulation:

if TheWorld.ismastersim then
    -- Server-only code
else
    -- Client-only code
end

Related Systems

• Entity replication system
• Event system
• Mod RPC system