gridfs_express.js

var express = require('express'),
    Mongo     = require('mongodb'),
    GridStore = Mongo.GridStore,
    Server    = Mongo.Server,
    ObjectID  = Mongo.ObjectID,
    Db        = Mongo.Db;

var app = express(),
    server = new Server('localhost', 27017, {auto_reconnect: true}),
    db = new Db('example', server);
    
db.open(function(err, db) {
  if (err) {
    console.log('Could not connect to MongoDB');
  } else {
    console.log('Connected to MongoDB');
  }
})


app.set('port', process.env.PORT || 8080);
app.use(app.router);

app.get('*', function (req, res) {
  var id = '.' + req.path;

  // Check for exist
  GridStore.exist(db, id, function (err, result) {
    if (true !== result) {
      return res.send(404);
    }

    // Create GridStore in READ mode
    new GridStore(db, id, "r").open(function (err, gridStore) {
      if (err) throw err;

      // Get read stream
      var readStream = gridStore.stream(true);

      readStream.on('close', function () {
        return;
      });

      // Simply 'pipe' read stream to write stream
      readStream.pipe(res);
    });
  });         
});

app.listen(app.get('port'), function() {
  console.log('Express server listening on port ' + app.get('port'));
});

module.exports = app;