34. Services and the data model

Everything in a Roblox experience hangs off one root object called game — the data model. Directly under it sit a fixed set of big containers called services: Workspace holds the 3D world, Players the people, ServerScriptService the server code. This chapter maps that top level, so you always know where to reach.

game and the services

game is the top of the tree from Chapter 32, and its children are services. You never create them — they always exist. The ones you meet first:

Getting a service: game:GetService

Reach a service reliably with game:GetService("Name"):

local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")

game.Players also works, but :GetService is the form Roblox docs use, and it is safer — it finds the service even where the plain dot form might not. Make it a habit at the top of every script.

workspace is special: it has its own lowercase global, so workspace means the same as game:GetService("Workspace").

Where code lives: server and client

Roblox runs your experience in two places at once, and where a script sits decides where it runs:

• A Script in ServerScriptService runs on the server — the shared computer hosting the game for everyone. Use it for anything that affects the whole world: spawning coins, keeping score.
• A LocalScript runs on a single player's device. Use it for what only that player sees: their screen, camera, and buttons.
• A ModuleScript is the shared module from Chapter 25. It runs nowhere by itself; other scripts require it.

This book's projects use a server Script, since they change the world for everybody.

Reaching across the tree

From any script you can walk from game to anywhere. A few patterns you'll reuse:

local Players = game:GetService("Players")

-- every player currently connected, as a list
for _, player in ipairs(Players:GetPlayers()) do
    print(player.Name)
end

-- a shared value other scripts can read, kept in ReplicatedStorage
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local roundTime = ReplicatedStorage:FindFirstChild("RoundTime")

Players:GetPlayers() returns a list you loop with ipairs, like any list from Chapter 22. Underneath, the tree is the same nested tables from Chapter 23 — services are just the top branches.

Homework

Written exercises. Paste into a Script in ServerScriptService to try.

Stuck or finished? Open the homework solutions page.