Store and retrieve binary file in MongoDB from Express via Mongolian

app.js

// Create
app.post('/api/attachments/stage', function(req, res) {
    var attachments = db.gridfs('attachments');
    var file = attachments.create({
        filename: shortid.generate()
    });

    var stream = file.writeStream();
    stream.on('close', function() {
        var attachment = {
            id: file.filename
        };

        res.send(attachment, 201);
    });

    req.pipe(stream);
});

// Read
app.get('/api/attachments/:id', function(req, res) {
    var attachments = db.gridfs('attachments');
    attachments.findOne(req.params.id, function(err, file) {
        if (err) return res.end(404);

        var stream = file.readStream();
        stream.pipe(res);
    });
});