I'm building a real time data system that allows an Apache/PHP server to send data to my Node.js server, which will then immediately send that data to the associated client via socket.io. So the Apache/PHP server makes a request that includes the data, as well as a user token that tells Node.js which user to send the data to.
Right now this is working fine - I've got an associative array that ties the user's socket.io connection to their user token. The problem is that I need to start scaling this to multiple servers. Naturally, with the default configs of socket.io I can't share connections between node workers.
The solution I had in mind was to use the RedisStore functionality, and just have each of my workers looking at the same Redis store. I've been doing research and there's a lot of documentation on how to use pub/sub functionality for broadcasting messages to large groups (rooms). That's fine, but I need to be able to send messages to a single client, so I need some way to retrieve a user's socket.io connection from the RedisStore.
The only way I can think to do this right now is to create a ton of 'rooms' named with the user's token, and only have one user in each room. Then I could just emit to that room. However, that seems very inefficient.
Is there a better way that I can retrieve user's unique socket.io connections from Redis?