URI Connection Settings

Optional connection settings are settings not covered by the URI Connection String . The following options are passed in the options parameter in the MongoClient.connect function.

const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');

// Connection URL
const url = 'mongodb://localhost:50000,localhost:50001';
// Database Name
const dbName = 'myproject';
// Use connect method to connect to the Server passing in
// additional options
MongoClient.connect(url, {
  poolSize: 10, ssl: true
}, function(err, client) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  client.close();
});

The table below shows all settings and what topology they affect.

Ensure your connection string is valid for Replica Sets

The connection string passed to the driver must use the fully qualified host names for the servers as set in the replicaset config. Given the following configuration settings for your replicaset.

{
	"_id" : "testSet",
	"version" : 1,
	"protocolVersion" : 1,
	"members" : [
		{
			"_id" : 1,
			"host" : "server1:31000",
		},
		{
			"_id" : 2,
			"host" : "server2:31001",
		},
		{
			"_id" : 3,
			"host" : "server3:31002",
		}
	]
}

You must ensure server1, server2 and server3 are resolvable from the driver for the Replicaset discovery and failover to work correctly.