Detecting extensions in Express.js (v3) route

index.js

var express = require('express'),
    app = express();

app.configure(function() {
  app.use(app.router);
  app.use(function(req, res, next) { res.send(404); });
});

app.get('/:name', function(req, res, next) {
  var re = /\.(csv|pdf)$/,
      matches = req.params.name.match(re);

  if (matches !== null && matches[1]) {
    switch (matches[1]) {
    case 'csv':
      res.type('text/csv');
      break;
    case 'pdf':
      res.type('application/pdf');
      break;
    }
  }

  res.format({
    'text/csv': function() {
      res.set({
        'Content-Disposition': 'attachment; filename="'+ req.params.name + '"'
      });
      res.send(new Buffer("csvData"));
    },
    'application/pdf': function() {
      // do pdf specific things here
    },
    json: function() {
      // built in support by express for AJAX calls
    },
    default: function() {
      res.send('<h1>'+req.params.name+'</h1>');
    }
  });
});

app.listen(3000);