Error handling in socket.use 3.x versions

[epexa]

Hello!

In the architecture of my project, there are public methods that do not require access, which are mixed with methods that require access.

Examples methods on client-side:

socket.emit('api.version', console.log); // public

socket.emit('events.get', console.log); // private

In 2.x versions there was a method socket.use which return: packet and next.

I could check if the method is public, because in each request I could get the method name. Like this:

io.on('connection', (socket) => {

	socket.use((packet, next) => {
		if (packet[0]) {
			const methodName = packet[0];
			const isPublicMethod = [
				'api.schema',
				'api.version',
			].includes(methodName);
			if ( ! isPublicMethod) return next(new Error('Need API key!'));
			else next();
		}
	});

How can I do this in 3.x versions?

This code is not working, I am getting an error: "Missing error handler on socket.".

In method socket.onAny (which return: event and ...args) cannot be called next.

For example, there is a method io.use (which return: socket and next) but it is not suitable as the event is called once on connection, not every time the methods are called.

[darrachequesne]

Hi! I've updated the documentation here: https://socket.io/docs/v4/server-socket-instance/#Socket-middlewares

Could you please check if that's clear enough?

[epexa]

Yes, that's what I need!
Thanks a lot!