cache-header.js

var app = express.createServer(
	(function(req, res, next) {
		if(req.url.indexOf("/stylesheets/") === 0) {
			res.setHeader("Cache-Control", "public, max-age=345600"); // 4 days
			res.setHeader("Expires", new Date(Date.now() + 345600000).toUTCString());
		}
		return next();
	}),
	express.static(__dirname + '/static')
);
app.listen(process.env.PORT || 8080);