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Callbacks

msk_core ships with a lightweight, framework-agnostic callback system that works in both directions:

  • Client → Server – the client triggers a callback that is registered on the server and waits for its return value.
  • Server → Client – the server triggers a callback that is registered on a specific client and waits for its return value.

The system is loaded eagerly into the core on both sides, so the underlying net-event handlers exist from the moment the resource starts. Consumers use the local view via shared_script '@msk_core/import.lua' and access it through the global MSK table, or through the matching exports.

All triggers are blocking: they internally use a promise and wait (with a 5 second timeout) until the response arrives, then return the result directly. There is no separate asynchronous callback parameter on the trigger side.

info

The registered callback always receives the player as its first argument (source), regardless of the direction. On the client, source is the player id passed in by the server-side trigger.

MSK.Register​

Registers a callback under a given name. Available on both sides.

  • On the server, the callback is function(source, ...) and is triggerable from the client.
  • On the client, the callback is function(source, ...) (where source is the player id provided by the server) and is triggerable from the server.

The server additionally supports a cb method: if the callback is triggered with MSK.TriggerCallback (client side), the registered server callback receives a cb function as its second argument which you call to return the result, e.g. function(source, cb, ...) cb(result) end. When triggered with the return method, you simply return the result instead.

Parameters
eventName - string - Unique name of the callback.
cb - function - The handler. Receives source first, followed by any arguments passed to the trigger.

MSK.Register(eventName, cb)

-- Example (Server): return method
MSK.Register('myscript:getMoney', function(source, account)
    local Player = MSK.GetPlayer({ source = source })
    return Player.getAccount(account).money
end)

-- Example (Server): cb method (used together with MSK.TriggerCallback on the client)
MSK.Register('myscript:getMoney', function(source, cb, account)
    local Player = MSK.GetPlayer({ source = source })
    cb(Player.getAccount(account).money)
end)

-- Example (Client): callback triggerable from the server
MSK.Register('myscript:getHeading', function(source)
    return GetEntityHeading(PlayerPedId())
end)

-- As an Export:
exports.msk_core:Register(eventName, cb)
Backwards compatibility (server only)

On the server, RegisterCallback and RegisterServerCallback are kept as aliases of MSK.Register. They behave identically and exist purely for compatibility with older scripts.

exports.msk_core:RegisterCallback(eventName, cb)
exports.msk_core:RegisterServerCallback(eventName, cb)

MSK.Trigger​

Triggers a registered callback and waits (blocking) for its return value. The signature differs per side.

  • Client → Server: MSK.Trigger(eventName, ...) — triggers the server callback eventName and returns its result.
  • Server → Client: MSK.Trigger(eventName, playerId, ...) — triggers the client callback eventName on playerId and returns its result.

If no response arrives within 5 seconds, the request times out and rejects.

Parameters (Client → Server)
eventName - string - Name of the registered server callback.
... - any - Optional arguments forwarded to the callback.

Parameters (Server → Client)
eventName - string - Name of the registered client callback.
playerId - number - The target player id.
... - any - Optional arguments forwarded to the callback.

Returns
... - any - The values returned by the callback.

MSK.Trigger(eventName, ...)

-- Example (Client → Server)
local money = MSK.Trigger('myscript:getMoney', 'bank')
print(money)

-- Example (Server → Client)
local heading = MSK.Trigger('myscript:getHeading', source)
print(heading)

-- As an Export:
exports.msk_core:Trigger(eventName, ...)

MSK.TriggerCallback​

Client only. Triggers a server callback using the cb method. This is functionally equivalent to MSK.Trigger for the consumer — it blocks and returns the result — but on the server the callback is invoked with a cb function it must call to return its result (see MSK.Register). Use this when the registered server callback resolves its value through cb(...) rather than return.

Parameters
eventName - string - Name of the registered server callback.
... - any - Optional arguments forwarded to the callback.

Returns
... - any - The values passed to the cb function on the server.

MSK.TriggerCallback(eventName, ...)

-- Example (Client)
local money = MSK.TriggerCallback('myscript:getMoney', 'bank')
print(money)

-- As an Export:
exports.msk_core:TriggerCallback(eventName, ...)