Mongo DB Native NodeJS Driver
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Check out the google group for questions/answers from users of the driver.


This is a node.js driver for MongoDB. It's a port (or close to a port) of the libary for ruby at

A simple example of inserting a document.

var client = new Db('test', new Server("", 27017, {})),
    test = function (err, collection) {
      collection.insert({a:2}, function(err, docs) {

        collection.count(function(err, count) {
          test.assertEquals(1, count);

        // Locate all the entries using find
        collection.find().toArray(function(err, results) {
          test.assertEquals(1, results.length);
          test.assertTrue(results.a === 2);

          // Let's close the db
    };, p_client) {
  client.collection('test_insert', test);


To enable the driver to use the C/C++ bson parser pass it the option native_parser:true like below

var client = new Db('integration_tests_20',
                    new Server("", 27017),

The version V0.8.0 > contains a C/C++ native BSON parser, this leads to some small changes in the way you need to access the BSON classes as you need to use the right versions of the classes with the right driver.

To access the correct version of BSON objects for your instance do the following


GitHub information

The source code is available at You can either clone the repository or download a tarball of the latest release.

Once you have the source you can test the driver by running

$ make test

in the main directory. You will need to have a mongo instance running on localhost for the integration tests to pass.


For examples look in the examples/ directory. You can execute the examples using node.

$ cd examples $ node queries.js


The GridStore class allows for storage of binary files in mongoDB using the mongoDB defined files and chunks collection definition.

For more information have a look at Gridstore


For more information about how to connect to a replicaset have a look at Replicasets


The current version does not support connection pooling, but it will be implemented soon.

Primary Key Factories

Defining your own primary key factory allows you to generate your own series of id's (this could f.ex be to use something like ISBN numbers). The generated the id needs to be a 12 byte long "string".

Simple example below

// Custom factory (need to provide a 12 byte array);
CustomPKFactory = function() {}
CustomPKFactory.prototype = new Object();
CustomPKFactory.createPk = function() {
  return new ObjectID("aaaaaaaaaaaa");

var p_client = new Db('integration_tests_20', new Server("", 27017, {}), {'pk':CustomPKFactory});, p_client) {
  p_client.dropDatabase(function(err, done) {
    p_client.createCollection('test_custom_key', function(err, collection) {
      collection.insert({'a':1}, function(err, docs) {
        collection.find({'_id':new ObjectID("aaaaaaaaaaaa")}, function(err, cursor) {
          cursor.toArray(function(err, items) {
            test.assertEquals(1, items.length);

            // Let's close the db

Strict mode

Each database has an optional strict mode. If it is set then asking for a collection that does not exist will return an Error object in the callback. Similarly if you attempt to create a collection that already exists. Strict is provided for convenience.

var error_client = new Db('integration_tests_', new Server("", 27017, {auto_reconnect: false}), {strict:true});    
  test.assertEquals(true, error_client.strict);, error_client) {
  error_client.collection('does-not-exist', function(err, collection) {
    test.assertTrue(err instanceof Error);
    test.assertEquals("Collection does-not-exist does not exist. Currently in strict mode.", err.message);

  error_client.createCollection('test_strict_access_collection', function(err, collection) {
    error_client.collection('test_strict_access_collection', function(err, collection) {
      test.assertTrue(collection instanceof Collection);
      // Let's close the db


If this document doesn't answer your questions, see the source of Collection or Cursor, or the documentation at MongoDB for query and update formats.


The find method is actually a factory method to create Cursor objects. A Cursor lazily uses the connection the first time you call nextObject, each, or toArray.

The basic operation on a cursor is the nextObject method that fetches the next object from the database. The convenience methods each and toArray call nextObject until the cursor is exhausted.


collection.find(query, [fields], options);

cursor.nextObject(function(err, doc) {});
cursor.each(function(err, doc) {});
cursor.toArray(function(err, docs) {});

cursor.rewind()  // reset the cursor to its initial state.

Useful options of find:

  • limit and skip numbers used to control paging.
  • sort an array of sort preferences like this: [['field1','asc'], ['field2','desc']]. As a shorthand, ascending fields can be written as simply the field name instead of ['field','asc']. Furthermore, if you are sorting by a single ascending field, you can smply enter the field name as a string without the surrounding array.
  • fields the fields to fetch (to avoid transferring the entire document)
  • tailable if true, makes the cursor tailable.
  • batchSize The number of the subset of results to request the database to return for every request. This should initially be greater than 1 otherwise the database will automatically close the cursor. The batch size can be set to 1 with batchSize(n, function(err){}) after performing the initial query to the database.
  • hint See Optimization: hint.
  • explain turns this into an explain query. You can also call explain() on any cursor to fetch the explanation.
  • snapshot prevents documents that are updated while the query is active from being returned multiple times. See more details about query snapshots.
  • timeout if false, asks MongoDb not to time out this cursor after an inactivity period.

For information on how to create queries, see the MongoDB section on querying.

var mongodb = require('mongodb');
var server = new mongodb.Server("", 27017, {});
new mongodb.Db('test', server, {}).open(function (error, client) {
  if (error) throw error;
  var collection = new mongodb.Collection(client, 'test_collection');
  collection.find({}, {limit:10}).toArray(function(err, docs) {



collection.insert(docs, options, [callback]);

Useful options:

  • safe:true Should always set if you have a callback.

See also: MongoDB docs for insert.

var mongodb = require('mongodb');
var server = new mongodb.Server("", 27017, {});
new mongodb.Db('test', server, {}).open(function (error, client) {
  if (error) throw error;
  var collection = new mongodb.Collection(client, 'test_collection');
  collection.insert({hello: 'world'}, {safe:true},
                    function(err, objects) {
    if (err) console.warn(err.message);
    if (err && err.message.indexOf('E11000 ') !== -1) {
      // this _id was already inserted in the database

Note that there's no reason to pass a callback to the insert or update commands unless you use the safe:true option. If you don't specify safe:true, then your callback will be called immediately. (fine for collecting some statistics, bad for most use cases (see "MongoDB is Web Scale")).

Update; update and insert (upsert)

The update operation will update the first document that matches your query (or all documents that match if you use multi:true). If safe:true, upsert is not set, and no documents match, your callback will be given an error.

See the MongoDB docs for the modifier ($inc, etc.) formats.


collection.update(criteria, objNew, options, [callback]);

Useful options:

  • safe:true Should always set if you have a callback.
  • multi:true If set, all matching documents are updated, not just the first.
  • upsert:true Atomically inserts the document if no documents matched.

Example for update:

var mongodb = require('mongodb');
var server = new mongodb.Server("", 27017, {});
new mongodb.Db('test', server, {}).open(function (error, client) {
  if (error) throw error;
  var collection = new mongodb.Collection(client, 'test_collection');
  collection.update({hi: 'here'}, {$set: {hi: 'there'}}, {safe:true},
                    function(err) {
    if (err) console.warn(err.message);
    else console.log('successfully updated');

Find and modify

findAndModify is like update, but it also gives the updated document to your callback. But there are a few key differences between findAndModify and update:

  1. The signatures differ.
  2. You can only findAndModify a single item, not multiple items.
  3. The callback does not get an error when the item doesn't exist, just an undefined object.


collection.findAndModify(query, sort, update, options, callback)

The sort parameter is used to specify which object to operate on, if more than one document matches. It takes the same format as the cursor sort (see Connection.find above).

See the MongoDB docs for findAndModify for more details.

Useful options:

  • remove:true set to a true to remove the object before returning
  • new:true set to true if you want to return the modified object rather than the original. Ignored for remove.
  • upsert:true Atomically inserts the document if no documents matched.

Example for findAndModify:

var mongodb = require('mongodb');
var server = new mongodb.Server("", 27017, {});
new mongodb.Db('test', server, {}).open(function (error, client) {
  if (error) throw error;
  var collection = new mongodb.Collection(client, 'test_collection');
  collection.findAndModify({hello: 'world'}, [['_id','asc']], {$set: {hi: 'there'}}, {},
                    function(err, object) {
    if (err) console.warn(err.message);
    else console.dir(object);  // undefined if no matching object exists.

Find or insert



The save method is a shorthand for upsert if the document contains an _id, or an insert if there is no _id.


Just as Felix Geisendörfer I'm also working on the driver for my own startup and this driver is a big project that also benefits other companies who are using MongoDB.

If your company could benefit from a even better-engineered node.js mongodb driver I would appreciate any type of sponsorship you may be able to provide. All the sponsors will get a lifetime display in this readme, priority support and help on problems and votes on the roadmap decisions for the driver. If you are interested contact me on for details.

And I'm very thankful for code contributions. If you are interested in working on features please contact me so we can discuss API design and testing.

Release Notes



  1. 10gen
  2. Google Closure Library
  3. Jonas Raoni Soares Silva


Copyright 2009 - 2010 Christian Amor Kvalheim.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.