authorization with socket.io

Question

I'm attempting to determine how best to authorize (in addition to authenticate) a user to perform a specific task using socket.io.

In express, this is fairly straightforward. I first have a login/password form that queries the database to determine if the record exists, and if it does exist, then I attach the User to the req.session data.

exports.session = function(req, res){
    User.authenticate(req.body.username, req.body.password, function(err, user){
        if (user){
            req.session.user = user;
            res.redirect('/');
        } else {
            console.log("authentication failed");
            res.render('user/login');
        }
    });
};

And once I have this, I can use middleware to authorize certain requests. For example,

app.put('/api/users/:userId', m.requiresLogin, m.isUser, api.putUser);

//Middleware
exports.isUser = function(req, res, next){
  if (req.session.user._id == req.user._id){
    next();
  } else {
    res.send(403);
  }
};

But I'm a bit confused about how to do this using socket.io. Say I have a event listener which alters a user's profile in the database, given that user's profile JSON object.

    socket.on('updateProfile', function(data){
    // query the database for data.user._id, and update it with the data attribute
    // but only do this if the data.user._id is equal to the user trying to do this. 
    });

Any suggestions as how to achieve this? Can it be done through the session information?

Answer 1

See the documentation here:

https://socket.io/docs/migrating-from-0-9/#authentication-differences

io.set('authorization', function (handshakeData, callback) {
// make sure the handshake data looks good
callback(null, true); // error first, 'authorized' boolean second 

});

Answer 2

It appears as though you're using Express.
I would highly recommend Express middleware called Passport (https://github.com/jaredhanson/passport).

Using Passport, you can implement any number of strategies to authenticate users (ex. OpenID through Google, Yahoo, Facebook; OAuth through Twitter, Facebook; or local strategies (ex. email registration)).

Finally, to answer your precise question: a project called passport.socketio is amazing in that it plays well with the above authentication strategies and, if you set Express's session, it will play well with that too. (https://github.com/jfromaniello/passport.socketio)