Validating Data

Technically, messages are just regular RemoteEvent / RemoteFunction calls, meaning that exploiters can send invalid data to function that run on server. To prevent that, WCS provides a way to attach validators to message arguments in your message config.

Validator is a regular function that accepts an argument and returns a boolean value. We'll be using a library called t in this example to validate arguments.

To attach validators to a message, you need to specify them inside your message config:

TypeScript

attack.ts

import { Skill, SkillDecorator } from "@rbxts/wcs";
import { t } from "@rbxts/t";

@SkillDecorator
export class Attack extends Skill {
    @Message({
        Type: "Event",
        Destination: "Client",
        Validators: [t.number, t.string],
    })
    protected printSomething(a: number, b: string) {
        print(a,b);
    }
}

Luau

attack.lua

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local WCS = require(ReplicatedStorage.WCS)
local t = require(ReplicatedStorage.t)

local Attack = WCS.RegisterSkill("Attack")

function Attack:printSomething(a,b)
    print(a,b)
end
WCS.DefineMessage(Attack.printSomething, {
    Type = "Event",
    Destination = "Client",
    Validators = {t.number, t.string},
})

return Attack

Each index in the Validators array corresponds to a function argument. From now, message calls that contain invalid arguments will be rejected.