Save file to Grid-fs

Grid-fs.js

var conn = mongoose.connection;
var Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo;

//grid-fs
var gfs = Grid(conn.db);

//create a file by filename
app.post('/foo/file', auth, function(req, res) {
  //so, this is a complete workaround to get a
  //non-form based multipart working
  //the problem here is that - mutlipart modules like multle does not
  //work cleanly for a non-form upload.
  //Went for the deprecated body-parser and the inbuilt multipart express
  //provides. it does not preserve file name in the req.body, so a custom header
  //with the filename works for now.
  //
  headers = JSON.stringify(req.headers)
  //console.log(req.headers["x_filename"])
  var options = {filename : req.headers["x_filename"]}
  gfs.exist(options, function (err, found) {
      if (err) throw err;
      if (!found){
        var writestream = gfs.createWriteStream({
          filename: req.headers["x_filename"]
        });
        req.pipe(writestream);
        writestream.on('finish', function (file) {
          console.log("Model updated into grid-db");
          res.send("Success!");
        });
      }
      else {
        res.send('File exists')
      }
    });

});