node.js sessionStore shows the same data for all sessions

I use node.js and want to store sessions in a KeyValue store. I tried Redis and MongoDB for this. In both cases I use the variable req.sessionStore for this, as in this example:

app.get('/user', parseParams, function(req,res) {
    data = req.sessionStore.userData || {};
    sendStringified(req,res,data);
});

But no matter in which browser I open my webapp, if I go to the site, it accesses the data of the last account I logged in from somewhere else. So only one user can be logged in at the same time. It seems to share the req.sessionData object over all sessions. Am I missing something?

If I go to my session db in the mongo client, and do a db.sesions.find(), it shows entries in this format:

{ "_id" : "CKMF8DfBpYNSCNyPIDj9ozVM.ZVo4d0/Oxrxdql44E6QL+U1AgtHWbGXLyX826YO1bDo", 
  "session" :  "{\"lastAccess\":1301358495277,
                 \"cookie\":{\"originalMaxAge\":14400000,\"expires\":\"2011-03-29T04:28:16.004Z\",\"httpOnly\":true,开发者_StackOverflow中文版\"path\":\"/\"},
                 \"oauth\":{\"token\":\"the_token\",\"token_secret\":\"the_secret\",\"verifier\":\"the _verifier\",\"access_token\":\"a_token\",\"access_token_secret\":\"a_t_s\"}}" }

I'm guessing your are using connect or express, so:

You don't interact with the stores directly. You just interact with req.session, and connect will use the store you configured.

I recommend you to take a look on the example provided on the rmongo store (the redis example was removed).

https://github.com/masylum/connect-mongodb/blob/master/examples/index.js