Group/rule-based authorization approach in node.js and express.js

Question

What are good strategies for role-based authorization in express.js? Especially with express-resource?

With Express-resource there are no handlers, so I think there are

Answer 1

In express you can add a handler that hooks into every operator (http://expressjs.com/guide.html#passing-route control) where you can do precondition validation. Here you can retrieve the role for the user and restrict access based on the HTTP verb (PUT, DELETE, etc.) or the URL (param('op') is 'edit' or so).

app.all('/user/:id/:op?', function(req, res, next){
  req.user = users[req.params.id];
  if (req.user) {
    next();
  } else {
    next(new Error('cannot find user ' + req.params.id));
  }
});