Question

I’m using socket.io and Redis together with node.js – code below.

I’m definitely being stupid here, but I can’t understand why the Redis event only fires with the first user who connects.

I see the NEW CONNECTION console message again for each user who opens the page, but I only see the REDIS console message with the first user.

io = io.listen(app);
client.flushall();
io.sockets.on('connection', function (socket) {

    // Update Redis with information about this connection. 
    console.log('*************** NEW CONNECTION');
    client.multi()
       .hmset("user:" + user_id, "nickname", nick)
       .sadd("chatroom:" + room_id, user_id)
       .exec();

    // Check that the Redis record was set. 
    client.smembers("chatroom:" + room_id, function (err, data) {
          if (err) { console.log(err); return; }
          console.log('REDIS CALL FOR chatroom:' + room_id, data);
    });
});

Do I need to create a separate Redis instance inside io.sockets.on for each client – and if so, will this scale?

Or otherwise, what am I doing wrong?

Answer 1

Got it! I was being stupid.

I was calling client.quit() inside socket.on('disconnect'...) – which was obviously deleting the Redis client altogether. DUH.

Hope this helps someone else in the future, anyway.