jsbin/lib/middleware.js

// Custom middleware used by the application.
module.exports = {
  // Transparently handle JSONP. Although this does require wrapping the
  // Request#send() method which is a bit nasty. Other alternative is to
  // always pass the response on and include this middleware after the
  // routes.
  jsonp: function () {
    return function (req, res, next) {
      var _send = res.send;
      res.send = function (body) {
        var callback = req.param('callback'),
            isJSONP  = res.get('Content-Type') === 'application/json' && callback;

        if (body && req.method !== 'HEAD' && isJSONP) {
          res.contentType('js');
          body = callback + '(' + body.toString().trim() + ');';
        }
        _send.call(this, body);
      };
      next();
    };
  },
  // Check for ajax requests and set the Request#ajax flag to true. 
  ajax: function () {
    return function (req, res, next) {
      req.ajax = false;
      if ((req.get('X-Requested-With') || '').toLowerCase() === 'xmlhttprequest') {
        req.ajax = true;
      }
      next();
    };
  },
  // Redirect urls with trailing slashes to their non-trailing counterpart,
  // requires the "strict routing" setting to be false.
  noslashes: function () {
    return function (req, res, next) {
      if (req.path !== '/' && req.path.slice(-1) === '/') {
        res.redirect(301, req.path.slice(0, -1));
      }
      next();
    };
  }
};