tw.callback

Side: Client + Server

Bidirectional client-server callback system. Register a callback on one side, trigger it from the other, with support for both synchronous and asynchronous calls.

Client Functions

tw.callback.register(name, handler)

Registers a client-side callback that can be triggered from the server.

Parameter	Type	Description
name	string	Unique callback name
handler	function	Handler function. Return value is sent back to the caller

Alias: tw.callback.registerCallback(name, handler)

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tw.callback.triggerServer(name, cb, ...)

Triggers a server-side callback from the client.

Parameter	Type	Description
name	string	Name of the server callback to trigger
cb	function or nil	Callback for async mode, or nil for synchronous (blocking via Citizen.Await)
...	any	Arguments passed to the server handler

Returns: When cb is nil, returns the server handler's return value(s) synchronously.

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tw.callback.triggerClient(name, cb, ...)

Triggers a local client-side callback (client-to-client).

Parameter	Type	Description
name	string	Name of the client callback to trigger
cb	function or nil	Callback for async mode, or nil for synchronous
...	any	Arguments passed to the handler

Server Functions

tw.callback.register(name, handler)

Registers a server-side callback. The source of the calling player is always injected as the first argument.

Parameter	Type	Description
name	string	Unique callback name
handler	function(source, ...)	Handler function. source is the player server ID

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tw.callback.register.latent(name, handler)

Registers a server-side callback with bandwidth-limited responses (latent events). Useful for sending large payloads back to the client without saturating the network.

Parameter	Type	Description
name	string	Unique callback name
handler	function(source, ...)	Handler function with bandwidth-limited response delivery

---

tw.callback.triggerServer(name, cb, ...)

Triggers a local server-side callback (server-to-server).

Parameter	Type	Description
name	string	Name of the server callback to trigger
cb	function or nil	Callback for async mode, or nil for synchronous
...	any	Arguments passed to the handler

---

tw.callback.triggerClient(name, target, cb, ...)

Triggers a client-side callback from the server.

Parameter	Type	Description
name	string	Name of the client callback to trigger
target	integer	Player server ID
cb	function or nil	Callback for async mode, or nil for synchronous
...	any	Arguments passed to the client handler

Examples

Register on server, call from client (async)

-- server.lua
tw.callback.register("getPlayerBalance", function(source)
    local user = tw.fw:getUser(source)
    return user:getMoney(0)
end)

-- client.lua
tw.callback.triggerServer("getPlayerBalance", function(balance)
    print("My balance: $" .. balance)
end)

Synchronous call from client

-- client.lua
local balance = tw.callback.triggerServer("getPlayerBalance", nil)
print("My balance: $" .. balance)

Register on client, call from server

-- client.lua
tw.callback.register("getPlayerCoords", function()
    return GetEntityCoords(PlayerPedId())
end)

-- server.lua
tw.callback.triggerClient("getPlayerCoords", source, function(coords)
    print("Player is at: " .. coords)
end)

Latent callback for large data

-- server.lua
tw.callback.register.latent("getAllShopItems", function(source)
    return Config.ShopItems -- large table sent with bandwidth control
end)

-- client.lua
local items = tw.callback.triggerServer("getAllShopItems", nil)

Notes

• Synchronous calls (cb = nil) use Citizen.Await and block the current thread until the response arrives.
• The source parameter is automatically injected on server-side handlers; do not pass it manually from the client.
• Use register.latent when the response payload is large to avoid network congestion.