📡 Events & Callbacks

Understanding Events

Events are the primary way to communicate between client and server scripts in RedM. They allow you to send messages, trigger actions, and share data across different parts of your resource.

Events enable asynchronous communication - you can trigger an event without waiting for a response!

Event Types

1. Client → Server Events

Send data from client to server:

-- CLIENT SIDE
TriggerServerEvent('eventName', arg1, arg2, arg3)

-- SERVER SIDE
RegisterNetEvent('eventName', function(arg1, arg2, arg3)
    local src = source -- Player who triggered the event
    print('Received from client', src, arg1, arg2, arg3)
end)

Real Example from RSG:

-- CLIENT SIDE (rsg-banking)
TriggerServerEvent('rsg-banking:server:transact', type, amount)

-- SERVER SIDE (rsg-banking)
RegisterNetEvent('rsg-banking:server:transact', function(type, amount)
    local src = source
    local Player = RSGCore.Functions.GetPlayer(src)
    if not Player then return end

    if type == 1 then -- Withdraw
        local currentBank = Player.Functions.GetMoney('bank')
        if currentBank >= amount then
            Player.Functions.RemoveMoney('bank', amount, 'bank-withdraw')
            Player.Functions.AddMoney('cash', amount, 'bank-withdraw')
        end
    elseif type == 2 then -- Deposit
        local currentCash = Player.Functions.GetMoney('cash')
        if currentCash >= amount then
            Player.Functions.RemoveMoney('cash', amount, 'bank-deposit')
            Player.Functions.AddMoney('bank', amount, 'bank-deposit')
        end
    end
end)

2. Server → Client Events

Send data from server to specific client(s):

-- SERVER SIDE
TriggerClientEvent('eventName', source, arg1, arg2, arg3)

-- To all clients
TriggerClientEvent('eventName', -1, arg1, arg2, arg3)

-- CLIENT SIDE
RegisterNetEvent('eventName', function(arg1, arg2, arg3)
    print('Received from server', arg1, arg2, arg3)
end)

Real Example from RSG:

-- SERVER SIDE (rsg-inventory)
TriggerClientEvent('rsg-inventory:client:updateInventory', src)

-- CLIENT SIDE (rsg-inventory)
RegisterNetEvent('rsg-inventory:client:updateInventory', function()
    -- Refresh inventory UI
    SendNUIMessage({
        action = 'update',
        inventory = RSGCore.Functions.GetPlayerData().items
    })
end)

3. Local Events (Same Side)

Events that stay on the same side (client-to-client or server-to-server):

-- CLIENT SIDE
TriggerEvent('eventName', arg1, arg2)

RegisterNetEvent('eventName', function(arg1, arg2)
    -- Handle event
end)

Local events on client do NOT sync between players. Each client’s local events are independent!

Event Security

Always Validate Server Events

NEVER trust data from client events! Always validate on server-side.

-- BAD - No validation
RegisterNetEvent('admin:giveWeapon', function(weaponName)
    local src = source
    -- Anyone can trigger this and become admin!
    exports['rsg-inventory']:AddItem(src, weaponName, 1, nil, nil, 'admin-given')
end)

-- GOOD - Proper validation
RegisterNetEvent('admin:giveWeapon', function(targetId, weaponName)
    local src = source
    local Player = RSGCore.Functions.GetPlayer(src)
    if not Player then return end

    -- Check permissions
    if not RSGCore.Functions.HasPermission(src, 'admin') then
        return -- Not admin, ignore
    end

    -- Validate weapon exists
    if not RSGCore.Shared.Weapons[weaponName] then
        return -- Invalid weapon
    end

    -- Validate target exists
    local Target = RSGCore.Functions.GetPlayer(targetId)
    if not Target then return end

    -- Now it's safe to give weapon
    exports['rsg-inventory']:AddItem(targetId, weaponName, 1, nil, nil, 'admin-given')
end)

Common Validation Patterns

RegisterNetEvent('shop:server:purchase', function(itemName, amount)
    local src = source
    local Player = RSGCore.Functions.GetPlayer(src)
    if not Player then return end

    -- Validate amount is reasonable
    if type(amount) ~= 'number' or amount < 1 or amount > 100 then
        return
    end

    -- Validate item exists
    local item = RSGCore.Shared.Items[itemName]
    if not item then return end

    -- Validate player has money
    local price = item.price * amount
    if Player.Functions.GetMoney('cash') < price then
        lib.notify(src, {
            description = 'Not enough money',
            type = 'error'
        })
        return
    end

    -- Process purchase
    Player.Functions.RemoveMoney('cash', price, 'shop-purchase')
    exports['rsg-inventory']:AddItem(src, itemName, amount, nil, nil, 'shop-purchase')
end)

Callbacks

Callbacks allow you to get a response from an event - like a function call across client/server!

RSGCore Callbacks

Server Callback (Most Common)

Ask the server for data from client:

-- SERVER SIDE - Create callback
RSGCore.Functions.CreateCallback('police:server:isPlayerCuffed', function(source, cb, targetId)
    local Target = RSGCore.Functions.GetPlayer(targetId)
    if not Target then
        cb(false)
        return
    end

    local isCuffed = Target.PlayerData.metadata.iscuffed or false
    cb(isCuffed)
end)

-- CLIENT SIDE - Trigger callback
RSGCore.Functions.TriggerCallback('police:server:isPlayerCuffed', function(isCuffed)
    if isCuffed then
        lib.notify({
            description = 'This player is cuffed',
            type = 'info'
        })
    else
        lib.notify({
            description = 'This player is not cuffed',
            type = 'error'
        })
    end
end, targetPlayerId)

Real Example from RSG:

-- SERVER SIDE (rsg-core)
RSGCore.Functions.CreateCallback('rsg-banking:server:getBankBalance', function(source, cb, bankType)
    local src = source
    local Player = RSGCore.Functions.GetPlayer(src)
    if not Player then
        cb(0)
        return
    end

    local balance = Player.Functions.GetMoney(bankType)
    cb(balance)
end)

-- CLIENT SIDE (rsg-banking)
RSGCore.Functions.TriggerCallback('rsg-banking:server:getBankBalance', function(balance)
    SendNUIMessage({
        action = 'updateBalance',
        balance = balance
    })
end, 'bank')

Client Callback

Ask the client for data from server:

-- CLIENT SIDE - Create callback
RSGCore.Functions.CreateClientCallback('getPlayerHeading', function(cb)
    local ped = PlayerPedId()
    local heading = GetEntityHeading(ped)
    cb(heading)
end)

-- SERVER SIDE - Trigger callback
RSGCore.Functions.TriggerClientCallback('getPlayerHeading', source, function(heading)
    print('Player heading is:', heading)
end)

Advanced Event Patterns

Pattern 1: Event with Confirmation

Send event and wait for confirmation:

-- CLIENT SIDE
local function tryPurchase(itemName)
    lib.notify({
        description = 'Processing purchase...',
        type = 'info'
    })

    TriggerServerEvent('shop:server:purchase', itemName)
end

-- Listen for confirmation
RegisterNetEvent('shop:client:purchaseSuccess', function(itemName)
    lib.notify({
        description = 'Purchased ' .. itemName,
        type = 'success'
    })
end)

RegisterNetEvent('shop:client:purchaseFailed', function(reason)
    lib.notify({
        description = 'Purchase failed: ' .. reason,
        type = 'error'
    })
end)

-- SERVER SIDE
RegisterNetEvent('shop:server:purchase', function(itemName)
    local src = source
    local Player = RSGCore.Functions.GetPlayer(src)
    if not Player then return end

    local success = -- ... purchase logic

    if success then
        TriggerClientEvent('shop:client:purchaseSuccess', src, itemName)
    else
        TriggerClientEvent('shop:client:purchaseFailed', src, 'Not enough money')
    end
end)

Pattern 2: Broadcast to Nearby Players

Send event only to players within range:

-- SERVER SIDE
local function notifyNearbyPlayers(coords, radius, message)
    local players = RSGCore.Functions.GetPlayersInScope(coords, radius)

    for _, playerId in ipairs(players) do
        TriggerClientEvent('chat:addMessage', playerId, {
            args = {'System', message}
        })
    end
end

-- Usage
local playerCoords = GetEntityCoords(GetPlayerPed(source))
notifyNearbyPlayers(playerCoords, 50.0, 'Gunshots nearby!')

Pattern 3: Chain Events

One event triggers another:

-- SERVER SIDE
RegisterNetEvent('job:server:clockIn', function(jobName)
    local src = source
    local Player = RSGCore.Functions.GetPlayer(src)
    if not Player then return end

    -- Update job duty status
    Player.Functions.SetJobDuty(true)

    -- Trigger client event to show notification
    TriggerClientEvent('job:client:onDuty', src, jobName)

    -- Trigger another server event for logging
    TriggerEvent('job:server:logDuty', src, jobName, true)
end)

RegisterNetEvent('job:server:logDuty', function(playerId, jobName, onDuty)
    -- Log to database or console
    print(string.format('Player %s %s for job %s', playerId, onDuty and 'clocked in' or 'clocked out', jobName))
end)

Event Handler Management

Removing Event Handlers

Sometimes you need to stop listening to events:

-- CLIENT SIDE
local eventHandler = nil

local function startListening()
    eventHandler = AddEventHandler('someEvent', function(data)
        print('Received:', data)
    end)
end

local function stopListening()
    if eventHandler then
        RemoveEventHandler(eventHandler)
        eventHandler = nil
    end
end

-- Usage
startListening()
-- ... do stuff ...
stopListening()

One-Time Events

Event that only triggers once:

-- CLIENT SIDE
local hasTriggered = false

RegisterNetEvent('tutorial:client:showWelcome', function()
    if hasTriggered then return end
    hasTriggered = true

    lib.notify({
        description = 'Welcome to the server!',
        type = 'info',
        duration = 10000
    })
end)

Performance Considerations

Don’t Spam Events

-- BAD - Sends event every frame!
CreateThread(function()
    while true do
        TriggerServerEvent('player:update', GetEntityCoords(PlayerPedId()))
        Wait(0)
    end
end)

-- GOOD - Sends event every 5 seconds
CreateThread(function()
    while true do
        TriggerServerEvent('player:update', GetEntityCoords(PlayerPedId()))
        Wait(5000)
    end
end)

-- BETTER - Only send when position actually changes
local lastCoords = vec3(0, 0, 0)

CreateThread(function()
    while true do
        local coords = GetEntityCoords(PlayerPedId())
        local distance = #(coords - lastCoords)

        if distance > 50.0 then -- Only if moved 50 units
            TriggerServerEvent('player:update', coords)
            lastCoords = coords
        end

        Wait(1000)
    end
end)

Batch Event Data

-- BAD - Multiple events
for i = 1, 100 do
    TriggerServerEvent('data:send', i)
end

-- GOOD - Single event with table
local dataToSend = {}
for i = 1, 100 do
    dataToSend[#dataToSend + 1] = i
end
TriggerServerEvent('data:sendBatch', dataToSend)

Common Event Naming Conventions

RSG Framework uses consistent naming:

resource:side:action

Examples:

rsg-inventory:server:AddItem
rsg-banking:client:updateBalance
police:server:cuffPlayer
hospital:client:revive

Follow this convention in your own resources for consistency!

Debugging Events

Print Event Triggers

-- SERVER SIDE
RegisterNetEvent('myevent', function(...)
    local args = {...}
    print('^2[EVENT RECEIVED]^7 myevent from', source)
    print('^3Arguments:^7', json.encode(args, {indent = true}))

    -- Your event logic here
end)

Event Listener Helper

-- CLIENT SIDE
local function debugEvent(eventName)
    AddEventHandler(eventName, function(...)
        print('^2[EVENT]^7', eventName, json.encode({...}))
    end)
end

-- Listen to all inventory events
debugEvent('rsg-inventory:client:updateInventory')
debugEvent('rsg-inventory:client:ItemBox')

Complete Example: Trading System

Putting it all together:

-- CLIENT SIDE
local function requestTrade(targetId)
    RSGCore.Functions.TriggerCallback('trade:server:requestTrade', function(accepted)
        if accepted then
            lib.notify({
                description = 'Trade request accepted!',
                type = 'success'
            })
            -- Open trade UI
        else
            lib.notify({
                description = 'Trade request declined',
                type = 'error'
            })
        end
    end, targetId)
end

RegisterNetEvent('trade:client:receiveRequest', function(requesterId)
    local requesterName = -- Get player name somehow

    lib.alertDialog({
        header = 'Trade Request',
        content = requesterName .. ' wants to trade with you',
        centered = true,
        cancel = true
    }, function(confirmed)
        TriggerServerEvent('trade:server:respondToRequest', requesterId, confirmed)
    end)
end)

-- SERVER SIDE
local pendingTrades = {}

RSGCore.Functions.CreateCallback('trade:server:requestTrade', function(source, cb, targetId)
    local src = source
    local Player = RSGCore.Functions.GetPlayer(src)
    local Target = RSGCore.Functions.GetPlayer(targetId)

    if not Player or not Target then
        cb(false)
        return
    end

    -- Store pending trade
    pendingTrades[targetId] = {
        requesterId = src,
        callback = cb
    }

    -- Notify target player
    TriggerClientEvent('trade:client:receiveRequest', targetId, src)

    -- Timeout after 30 seconds
    SetTimeout(30000, function()
        if pendingTrades[targetId] then
            pendingTrades[targetId].callback(false)
            pendingTrades[targetId] = nil
        end
    end)
end)

RegisterNetEvent('trade:server:respondToRequest', function(requesterId, accepted)
    local src = source

    if pendingTrades[src] and pendingTrades[src].requesterId == requesterId then
        pendingTrades[src].callback(accepted)
        pendingTrades[src] = nil
    end
end)

Summary

Event Type	Trigger From	Received On	Use Case
Server Event	Client	Server	Player actions, requests
Client Event	Server	Client(s)	Updates, notifications
Local Event	Same side	Same side	Internal communication
Callback	Either	Other side	Get data, confirmations

Next Steps

Threads & Loops - Creating continuous processes
Common Patterns - RSG Framework best practices
Performance Tips - Optimize your code

Need more help? Join the RSG Framework Discord!

Lua Fundamentals

​Understanding Events

​Event Types

​1. Client → Server Events

​2. Server → Client Events

​3. Local Events (Same Side)

​Event Security

​Always Validate Server Events

​Common Validation Patterns

​Callbacks

​RSGCore Callbacks

​Server Callback (Most Common)

​Client Callback

​Advanced Event Patterns

​Pattern 1: Event with Confirmation

​Pattern 2: Broadcast to Nearby Players

​Pattern 3: Chain Events

​Event Handler Management

​Removing Event Handlers

​One-Time Events

​Performance Considerations

​Don’t Spam Events

​Batch Event Data

​Common Event Naming Conventions

​Debugging Events

​Print Event Triggers

​Event Listener Helper

​Complete Example: Trading System

​Summary

​Next Steps

Understanding Events

Event Types

1. Client → Server Events

2. Server → Client Events

3. Local Events (Same Side)

Event Security

Always Validate Server Events

Common Validation Patterns

Callbacks

RSGCore Callbacks

Server Callback (Most Common)

Client Callback

Advanced Event Patterns

Pattern 1: Event with Confirmation

Pattern 2: Broadcast to Nearby Players

Pattern 3: Chain Events

Event Handler Management

Removing Event Handlers

One-Time Events

Performance Considerations

Don’t Spam Events

Batch Event Data

Common Event Naming Conventions

Debugging Events

Print Event Triggers

Event Listener Helper

Complete Example: Trading System

Summary

Next Steps