acha-framework/src/backend/file-helper.js

is a modular framework on both client (angular.js) and server (node.js) side, it provides security, orm, ioc, obfuscation and ...

(function (undefined) {
  Ioc.define('backend.fileHelper', [], function (provide) {
    provide({
      isFile: function (url) {
        'use strict';
        return (url || '').match(/\.([0-9a-z]+)(?:[\?#]|$)/i);
      },
      downloadStream: function (fileName, res, attachment) {
        FS.stat(fileName, function (err, stat) {
          if (err) {
            res.status(404).send();
            return;
          }
          res.writeHead(200, {
            'Content-Type': MIME.lookup(fileName),
            'Content-Length': stat.size,
            'Content-disposition': attachment === true ? 'attachment; filename=' + PATH.basename(fileName) : undefined
          });
          var readStream = FS.createReadStream(fileName);
          readStream.pipe(res);
        });
      }
    });
  });
}());