Express routes parameter conditions

I have a route on my Express app that looks like this:

app.get('/:id', function (request, response) {
  …
});

The ID will always be a number. However, at the moment this route is matching other things, such as /login.

I think I want two things from this:

1. to only use this route if the ID is a number, and
2. only if there isn't a route for that specific paramater already defined (such as the clash with /login).

Can this be done?

Expanding on Marius's answer, you can provide the regex AND the parameter name:

app.get('/:id(\\d+)/', function (req, res){
  // req.params.id is now defined here for you
});

Yes, check out http://expressjs.com/guide/routing.html and https://www.npmjs.com/package/path-to-regexp (which express uses). An untested version that may work is:

app.get(/^(\d+)$/, function (request, response) {
  var id = request.params[0];
  ...
});

You can use:

// /12345
app.get(/\/([^\/]+)\/?/, function(req, res){
  var id = req.params[0];
  // do something
});

or this:

// /post/12345
app.get(/\/post\/([^\/]+)\/?/, function(req, res){
  var id = req.params[0];
  // do something
});