If you are working with Socket.IO and Express Framework while developing your applications you must know they work together so Socket.IO will listen on the same port that your HTTP/S server and will serve the requests by that way, but Socket.IO doesn't works on the same paradigm where you pass a middleware to the route and you could get authentication on this manner. Instead, you must configure Socket.IO with a global authorization method or a handshake authorization manner.
Since in my applications I serve cookies already where I save session info and this is already stored in Redis with help of the module connect-redis then I should be able to get this info onto Socket.IO authorization method and with this allow only to authorized users to get info from my websockets.
I found how to do it with the default session-store in-memory from Express, and adapted that so it could work with Redis.
Here's the snippet:
Hope anyone can found it useful!