Mongo-dart - MongoDB driver for Dart programming language

Server-side driver library for MongoDb implemented in pure Dart.

Basic usage

Obtaining connection

  var db = Db("mongodb://localhost:27017/mongo_dart-blog");
  await db.open();

or

  var db = await Db.create("mongodb+srv://<user>:<password>@<host>:<port>/<database-name>?<parameters>");
  await db.open();

Querying

Method find returns stream of maps and accept query parameters, usually build by fluent API query builder provided by mongo_dart_query as top level getter where

  var coll = db.collection('user');
  await coll.find(where.lt("age", 18)).toList();
  
  //....
  
  await coll
      .find(where.gt("my_field", 995).sortBy('my_field'))
      .forEach((v) => print(v));

  //....
  
  await coll.find(where.sortBy('itemId').skip(300).limit(25)).toList();
  

Method findOne take the same parameter and returns Future of just one map (mongo document)

  val = await coll.findOne(where.eq("my_field", 17).fields(['str_field','my_field']));

Take notice in these samples that unlike mongo shell such parameters as projection (fields), limit and skip are passed as part of regular query through query builder

Inserting documents

  await usersCollection.insertAll([
    {'login': 'jdoe', 'name': 'John Doe', 'email': '[email protected]'},
    {'login': 'lsmith', 'name': 'Lucy Smith', 'email': '[email protected]'}
  ]);

Updating documents

You can update whole document with method save

  var v1 = await coll.findOne({"name": "c"});
  v1["value"] = 31;
  await coll.save(v1);

or you can perform field level updates with method update and top level getter modify for ModifierBuilder fluent API

  coll.update(where.eq('name', 'Daniel Robinson'), modify.set('age', 31));

Removing documents

  students.remove(where.id(id));
  /// or, to remove all documents from collection
  students.remove();

Simple app on base of JSON ZIPS dataset

import 'package:mongo_dart/mongo_dart.dart';

void main() async {
  void displayZip(Map zip) {
    print(
        'state: ${zip["state"]}, city: ${zip["city"]}, zip: ${zip["id"]}, population: ${zip["pop"]}');
  }
  var db =
      Db("mongodb://reader:[email protected]:37468/samlple");
  var zips = db.collection('zip');
  await db.open();
  print('''
******************** Zips for state NY, with population between 14000 and 16000,
******************** reverse ordered by population''');
  await zips
      .find(where
          .eq('state', 'NY')
          .inRange('pop', 14000, 16000)
          .sortBy('pop', descending: true))
      .forEach(displayZip);
  print('\n******************** Find ZIP for code 78829 (BATESVILLE)');
  var batesville = await zips.findOne(where.eq('id', '78829'));
  displayZip(batesville);
  print('******************** Find 10 ZIP closest to BATESVILLE');
  await zips
      .find(where.near('loc', batesville["loc"]).limit(10))
      .forEach(displayZip);
  print('closing db');
  await db.close();
}

Building aggregation queries

import 'package: mongo_dart/mongo_dart.dart';

main() async {
  final db = Db('mongodb://127.0.0.1/testdb');
  final pipeline = AggregationPipelineBuilder()
    .addStage(
      Match(where.eq('status', 'A').map['\$query']))
    .addStage(
      Group(
        id: Field('cust_id'),
        fields: {
          'total': Sum(Field('amount'))
        }
      )).build();
  final result =
    await DbCollection(db, 'orders')
      .aggregateToStream(pipeline).toList();
  result.forEach(print);
}

Secure connection

You can connect using a secured tls/ssl connection in one of these two ways:

• setting the secure connection parameter to true in db.open()

    await db.open(secure: true);

• adding a query parameter => "tls=true" (or "ssl=true").

    var db = DB('mongodb://www.example.com:27017/test?tls=true&authSource=admin');
              or
    var db = DB('mongodb://www.example.com:27017/test?ssl=true&authSource=admin');

When you use the mongodb+srv url schema, the "tls" (or "ssl") parameter is implicitly considered true.

You can also use certificates for tls handshake see this tutorial for more info.

Atlas (MongoDb cloud service) connection

Atlas requires a tls connection, so now it is possible to connect to this cloud service. When creating a cluster Atlas shows you three ways of connecting: Mongo shell, Driver and MongoDb Compass Application. The connection string is in Seedlist Connection Format (starts with mongodb+srv://).

Take the Url related to the Driver mode and pass it to Db.create().

Please, not that Db.create is an asynchronous constructor, so you have to await for it.

  var db = await Db.create("mongodb+srv://<user>:<password>@<host>:<port>/<database>?<parameters>");
  await db.open();

OP_MSG

Only for those using mongodb version 3.6 or later State: experimental

Donate If you need a reliable driver like I do, please help me maintaining this software with a donation. This will allow me to dedicate more time on development, testing and documentation.

Starting from 3.6, a new protocol has been developed form mongodb to exchange data with the server. We are updating all commands and operation so that we can use the new protocol. This will be done gradually. At present we have developed the following operations:

Command	Status	Legacy alternative	Notes
-	Not developed	Save	This method has been deprecated.
insertOne	Tested	legacyInsert	The old method insert is a wrapper that calls insertOne if you are running MongoDb 3.6 or later, otherwise legacyInsert.
insertMany	Tested	legacyInsertAll	Allows to insert many documents in one command. It is subject to the max number of documents per message limit (at present <4.4> 100,000).The old method insertAll is a wrapper that calls insertMany if you are running MongoDb 3.6 or later, otherwise legacyInsertAll.
deleteOne	Tested	-	Allows to delete one document. Example Example 2
deleteMany	Tested	legacyRemove	The old method remove is a wrapper that calls deleteMany if you are running MongoDb 3.6 or later, otherwise legacyRemove. Allows to delete many documents in one commnand. Example
updateOne	Tested	-	Allows to update one document Example
updateMany	Tested	-	Allows to update many documents in one command. Example
modernUpdate	Tested	legacyUpdate	The old method update now is only a wrapper. If you are running MongoDb 3.6 or later, modernUpdate is called, otherwise legacyUpdate
-	To be developed yet	count
modernDistinct	Experimental	legacyDistinct	The old method distinct now is only a wrapper. If you are running MongoDb 3.6 or later, modernDistinct is called, otherwise legacyDistinct
modernFind	Tested	legacyFind	The old method find now is simply a wrapper. If you are running MongoDb 3.6 or later, modernFind is called, otherwise legacyFind
modernFindOne	Tested	legacyFindOne	The old method findOne now is simply a wrapper. If you are running MongoDb 3.6 or later, modernFindOne is called, otherwise legacyFindOne
modernFindAndModify	Tested	legacyFindAndModify	The old method findandModify now is simply a wrapper. If you are running MongoDb 3.6 or later, modernFindAndModify is called, otherwise legacyFindAndModify
modernAggregate	Tested	legacyAggregateToStream	The old method aggregateToStream now is simply a wrapper. If you are running mongoDb 3.6 or later, modernAggregate is called, otherwise legacyAggregateToStream
modernAggregateCursor	Tested	-	This method has no corresponding legacy one, as it returns a cursor and not a Map like the legacy aggregate
-	Production	aggregate	The legacy method aggregate has no corresponding "modern" method. It returns a Map. Is it used?
watch	Tested	-	This method has no corresponding legacy methods. Allows to monitor changes in a collection. Examples: watch selecting records - watch all insert operations
watchCursor	Experimental	-	This method has no corresponding legacy methods. Like watch, but returns a cursor instead of a stream. Normally you will only need watch

There is the new collection helper method bulkWrite. The syntax is quite similar to that of the shell: collection.bulkWrite([{'insertOne': {'document': { "_id" : 1, "char" : "Brisbane", "class" : "monk", "lvl" : 4 }}}]); Like the one in the shell you can define the insertOne, deleteOne, deleteMany, updateOne, updateMany and replaceOne. In addition to the shell operation, you can use also an insertMany operation, with the following syntax: collection.bulkWrite([{'insertMany': {'documents': [{ "_id" : 1, "char" : "Brisbane", "class" : "monk", "lvl" : 4 }]}}]); Unlike the insertMany helper, this bulk operation does not suffer of the max number of documents per message limitation. You can also use directly the Bulk Object, if you prefer. Some examples: ordered Collection helper, unordered collection helper, ordered Bulk class and unordered Bulk Class

Aside to these changes we have also to mention the new Decimal128 type management (that is backed by the Rational class). This is inherited from enhancements in the BSON package

Last but not least, some commands:

Command	Status	Legacy alternative	Notes
createIndex	Production	db.createIndex	This was needed because the legacy method didn't work any more starting from release 4.0
createCollection	Experimental	-	Explicitly creates a collection. Useful if you want to create a capped collection or assign a collation to the collection.
createView	Experimental	-	Creates a view
getParameterCommand	Experimental	-	Allows to get a specific server parameter
getAllParametersCommand	Experimental	-	Returns all config parameters
killCursorCommand	Experimental	MongoKillCursorMessage	Used internally to close an unexhausted cursor.
getMoreCommand	Experimental	MongoGetMoreMessage	Used internally to read a new batch of data from the server
getLastErrorCommand	Experimental	DbCommand.createGetLastErrorCommand	Used internally to return the status of the previous operation. It is no more needed with the modern operations, but, for compatibility reasons, it can be used still.
serverStatus	Experimental	serverStatus	The method was already present, but it has been improved giving the possiblity to return a class with all the values instead of a map

See also

• API Doc

• Status

• Recent change notes

• Additional examples and tests