Node.js/Express: Add Expires header to /images and /stylesheets directories

server.js

/**
 * Module dependencies.
 */

var express = require('express')
  , routes = require('./routes')
  , user = require('./routes/user')
  , http = require('http')
  , path = require('path');

var app = express();

app.configure(function(){
  app.set('port', process.env.PORT || 3000);
  app.set('views', __dirname + '/views');
  app.set('view engine', 'jade');
  app.use(express.logger('dev'));
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(app.router);
  app.use(express.static(path.join(__dirname, 'public')));
});

app.configure('development', function(){
  app.use(express.errorHandler());
});

app.get('/*', function (req, res, next) {

  if (req.url.indexOf("/images/") === 0 || req.url.indexOf("/stylesheets/") === 0) {
    res.setHeader("Cache-Control", "public, max-age=2592000");
    res.setHeader("Expires", new Date(Date.now() + 2592000000).toUTCString());
  }
  next();
});

app.get('/', routes.index);

http.createServer(app).listen(app.get('port'), function(){
  console.log("Express server listening on port " + app.get('port'));
});