Version: 3.0.9

Writing custom middleware

If you want to write a custom middleware (e.g. for logging, or other purposes), you must write a Net.Middleware compatible function. This is similar to a middleware function in rodux.

This function is given a callback nextEvent, and instance (the remote instance).

It expects you to return a function, which is given the sender, and the args (arguments) after that, that were passed. This inner function should call and return nextEvent (if you want it to succeed) - or return nothing (if you don't want your remote to succeed with calling)

roblox-ts
luau

Middleware Type Signature

type NetMiddleware<CallArguments, PreviousCallArguments> = 
    (next: (player: Player, ...args: CallArguments) => void, event: NetManagedInstance) 
        => (sender: Player, ...args: PreviousCallArguments) => void;

export const MyMiddleware: Net.Middleware = (nextMiddleware, instance) => {
    return (sender, ...args) => {
        return nextMiddleware(sender, ...args);
    };
};

For example, if we want a specific remote to only be callable by administrators in our game:-

roblox-ts
luau

const GROUP_ID = 2664663; //  Group id would go here
export const AdministratorMiddleware: Net.Middleware = (nextMiddleware, instance) => {
    return (sender, ...args) => {
        if (sender.GetRankInGroup(GROUP_ID) >= 250) {
            // This would continue the remote execution
            return nextMiddleware(sender, ...args);
        }

        // Otherwise the remote request is ignored
    };
};

The above middleware, when applied to a remote will only continue and call the callback/listener if the next/nextMiddleware callbacks are called. Otherwise RbxNet will drop these requests.