QBCore in depth: the player and their money · Lesson 3/4 · 9 min

QBCore callbacks: requesting data from the server

When the client needs an answer from the server (do I have a balance? what items do I have?), you use a callback.

A normal event is one-way (the client notifies the server). But sometimes the client needs a RESPONSE: "do I have enough money for this?". That's what QBCore callbacks are for.

On the server: register the callback

lua

QBCore.Functions.CreateCallback('tienda:comprar', function(source, cb, precio)
  local Player = QBCore.Functions.GetPlayer(source)
  if not Player then return cb(false) end
  if Player.Functions.RemoveMoney('cash', precio, 'compra') then
    cb(true)   -- respond to the client: purchase OK
  else
    cb(false)  -- no money
  end
end)

server.lua

On the client: call it and wait for the response

lua

QBCore.Functions.TriggerCallback('tienda:comprar', function(exito)
  if exito then
    print('Purchase completed')
  else
    print('You don\'t have enough money')
  end
end, 1500) -- 1500 = price passed to the server

client.lua

The decision (do they have money?) and the charge happen on the SERVER. The client only receives yes/no. That way no cheating is possible. And like in ESX: call cb() on ALL paths, or the client hangs.

Practice what you learned

0/3

Test

¿Cuándo necesitas un callback de QBCore en lugar de un evento normal?

Rellena los huecos

Completa el registro del callback de servidor que responde sí/no.

1QBCore.Functions.('tienda:comprar', function(source, cb, precio)

2 local Player = QBCore.Functions.GetPlayer(source)

3 if not Player then return cb(false) end

4 cb(true)

5end)

Pista

En el servidor se registra; en el cliente se dispara con TriggerCallback.

Ordena el código

Ordena la llamada del cliente que pide la compra al servidor y reacciona a la respuesta.

Coloca las líneas en el orden correcto con las flechas.

print('Compra realizada')

QBCore.Functions.TriggerCallback('tienda:comprar', function(exito)

end

end, 1500)

else

print('No tienes suficiente dinero')

if exito then

Pista

TriggerCallback recibe el nombre, la función que maneja la respuesta y, al final, los argumentos (el precio 1500).

Challenge: code it yourself

Create a callback that returns true only if the player has the 'police' job.

Write it yourself in your editor (VS Code) and test it on your server. You learn here by doing it, not by copying.

See hint

Compare Player.PlayerData.job.name == 'police' and respond with cb(true/false).

Escribe aquí tu solución:

← The Player object and its money Next: Metadata and player identity

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