How to store socket'a id in database to send messages?

Question

MongoDB

Greetings. The problem is this - with each connection to the Socket.IO server, a unique ID is created for the client at the moment of handshake, in order to send a message to this client - you need to know its id.
How to be? To write down it in basis at each connection?
My only idea is to make something like users_online in Redis and store it as user_id => socket_id. In Redis, because it works in memory, so all calls to it will be faster.
PS Redis saves data to disk periodically, how can it be Only-Memory?

Answer 1

No need to store in databases, store in memory, the node is also always in memory, it is not necessary to access an external process such as a radish. If the process is parade, then its connections also fall and these IDs are no longer needed by anyone. If there are several processes, then use message buses, ZeroMQ, RabbitMQ, etc.