expressjs: Sending a file from parent directory

Question

I would like to use expressjs's sendfile to send a file from a parent directory of the script file. What I tried to do is this:

app.get('/', function(req, res){
    res.sendfile('../../index.html');
});

I get a forbidden error because apparently, sendfile does not trust path traversal. So far I've been unable to figure out how to change the directory for files sent via sendfile. Any hints?

Edit: I was kind of tired when posting this, in fact it is kind of easy. I'll leave it here in case anybody else stumbles upon this. There's an option parameter for sendfile that allows you to do just that, like so:

app.get( '/', function( req, res ){
    res.sendfile('index.html', { root: "../../"});
});

Answer 1

You have to mention root as the second parameter of sendfile().

For example:

app.get('/:dir/:file', function(req, res) {
  var dir = req.params.dir,
      file = req.params.file;

  res.sendfile(dir + '/' + file, {'root': '../'});
});

You can find more details here: https://github.com/visionmedia/express/issues/1465

Answer 2

You need to use express.static.

Say you have the following directory set up:

/app
   /buried
       /deep
           server.js
   /public
       index.html

Then you should have the following Express configuration:

var express = require('express');
var server = express.createServer();
server.configure(function(){
    server.use(express.static(__dirname + '../../public'));
});
server.listen(3000);

res.sendfile is meant for "finer-grain" transferring of files to the client. See API docs for example.