nazomikan/app.js

## app.js
var http = require('http')
  , connect = require('connect')
  , app
  ;

app = connect()
  .use(assetsExpire(1000 * 60 * 3))
  .use(connect.static('public'))
  .use(function(req, res){
    res.end(' \
<html> \
<head> \
<script type="text/javascript" src="/hoge.js"></script> \
</head> \
<body>hello world</body> \
</html> \
    ');
  });

http.createServer(app).listen(3000);

/**
 * 静的ファイル(js, css)のキャッシュ（expireの）設定
 *
 * @param {Number} expire expireの有効期間(単位ms)
 * @return {Function} middleware
 */
 function assetsExpire(expire) {
  var url = require('url')
    , path = require('path')
    ;

  // set default value
  expire = expire == null ? (1000 * 60 * 30) : expire;

  return function (req, res, next) {
    var pathname = url.parse(req.url).pathname
      , ext
      , now
      ;

    // 拡張子取得
    ext = path.extname(pathname);
    if (!ext) {
      return next();
    }

    switch(ext) {
    case '.js':
    case '.css':
      now = (new Date(Date.now() + expire)).toUTCString();
      res.setHeader('Expires', now);
      res.setHeader('Cache-Control', "max-age=" + (expire / 1000));
    default:
      next();
    }
  };
}

## hoge.js
// public/hoge.js
console.log("hello world");
	var http = require('http')
	, connect = require('connect')
	, app
	;

	app = connect()
	.use(assetsExpire(1000 * 60 * 3))
	.use(connect.static('public'))
	.use(function(req, res){
	res.end(' \
	<html> \
	<head> \
	<script type="text/javascript" src="/hoge.js"></script> \
	</head> \
	<body>hello world</body> \
	</html> \
	');
	});

	http.createServer(app).listen(3000);

	/**
	* 静的ファイル(js, css)のキャッシュ（expireの）設定
	*
	* @param {Number} expire expireの有効期間(単位ms)
	* @return {Function} middleware
	*/
	function assetsExpire(expire) {
	var url = require('url')
	, path = require('path')
	;

	// set default value
	expire = expire == null ? (1000 * 60 * 30) : expire;

	return function (req, res, next) {
	var pathname = url.parse(req.url).pathname
	, ext
	, now
	;

	// 拡張子取得
	ext = path.extname(pathname);
	if (!ext) {
	return next();
	}

	switch(ext) {
	case '.js':
	case '.css':
	now = (new Date(Date.now() + expire)).toUTCString();
	res.setHeader('Expires', now);
	res.setHeader('Cache-Control', "max-age=" + (expire / 1000));
	default:
	next();
	}
	};
	}