Question

First Problem
I’m trying to figure out sessions, stores, authorization, and redis. If it’s important, I am using Express@3.0.0rc4. I understand that I have two options to put my RedisStore(). Which one do I use? Do I use both?

express.session({secret: 'secret', key: 'key', store: new RedisStore()});
io.set('store', new RedisStore());

I already have node.js, express, and socket.io running. So now I’m trying to implement redis but I don’t know how to implement authorization using sessions/stores and I don’t know how to write to the redis database. I haven’t found any documentation on this. I found a site that talks about sessions and stores using socket.io and express but no redis, and another one that talks about sessions and stores using all three, but it doesn’t use io.set('store', ...).

I also don’t know if I should use two different stores, one for express and one for socket.io, or if I should just use one. Look at the example for clarification:

//Redis Variables
var redis = require('socket.io/node_modules/redis');
var RedisStore = require('socket.io/lib/stores/redis');
var pub = redis.createClient();
var sub = redis.createClient();
var client = redis.createClient();
var redis_store = new RedisStore({
                        redisPub: pub,
                        redisSub: sub,
                        redisClient: client
                      });

app.configure(function(){
  //...code goes here...
  app.use(express.session({
                    secret: 'secret',
                    key: 'key',
                    store: redis_store  //Notice I'm using redis_store
                  }));
  //...more code...
});

io.configure(function(){
  io.set('store', redis_store);  //Notice it's the same RedisStore() being used
});

Do I use the same RedisStore() for each? Do I create seperate ones for each? Do I just use express or socket.io? What I really want is to be able to authenticate clients (I assume that’s done through sessions) and have them update the redis database when they connect – keeping a log of when people accessed my site. Which leads to my second problem.

---

Second Problem
So I have no idea how to access and edit the redis database from this point. I haven’t been able to test this because of my first problem but I assume it would be something like this:

io.sockets.on('connection', function(socket){
  var session = socket.handshake.session;
  redis.put(session);
});

I also haven’t seen any documentation on how to update a redis database from within node.js so I highly doubt that redis.put() is the correct terminology haha. I have visited redis’s website but I can’t find commands for node.js. Just commands for using regular redis from the command line. Anyways, if someone could at least point me in the right direction that would be great. Thanks. 🙂

Answer 1

Express and Socket.IO have their own integration with Redis for session management, as you’ve seen. It is designed as a blackbox integration, the idea being that the session store implementation is independent from the rest of your code. Since it’s independent, that means you can’t go in and use express or socket.io to access Redis directly. You’ll need to add a regular redis client like node_redis. The benefit is you don’t have to worry about making all those redis calls yourself, instead you’ll be interacting with express or socket.io’s session store interfaces.

So in your #1 case, you could pass in a single new instance of RedisStore, not two new ones as you’ve done. Or you could follow your second link and have socket.io listen through express. In that case it would integrate with express session management. That’s why you don’t see the extra io.set(‘store’) call in that example.

It’ll probably seem redundant to you, but try to think of RedisStore as a special client designed only for session management. Even thought RedisStore probably relies on something like node_redis, you shouldn’t try to access it. You have to include another library for accessing your redis database directly, assuming you wanted to store other non-session items in redis in the first place.