Warning on Connecting to MongoDB with a Node server

Question

Connecting with MongoDB native driver

I wrote following code to connect mongodb through native driver which has been install with npm install mongodb --save

const MongoClient = require("mongodb").MongoClient;
const url = "mongodb://127.0.0.1:27017";

const dbName = "game-of-thrones";
let db;

MongoClient.connect(
url,
 { useNewUrlParser: true },
  (err, client) => {
    if (err) return console.log(err);

  db = client.db(dbName);
   console.log(`Connected MongoDB: ${url}`);
   console.log(`Database: ${dbName}`);
  }
);

When I write on the terminal node server.js I got following error

(node:3500) DeprecationWarning: current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to MongoClient.connect. Connected MongoDB: mongodb://127.0.0.1:27017 Database: game-of-thrones

The database is connected, but how can I get rid out from the warning

Answer 1

Check your mongo version

 mongo --version

If you are using version >= 3.1.0 change you mongo connection file to ->

 MongoClient.connect("mongodb://localhost:27017/YourDB", {
   useNewUrlParser: true,
   useUnifiedTopology: true
 })

For details about the useUnifiedTopology option added in 3.2.1, see https://github.com/mongodb/node-mongodb-native/releases/tag/v3.2.1

Answer 2

My advice is to leave it as it is (maybe place a warning). The useUnifiedTopology: true option does not work correctly.

More precisely, in the event of a loss of connection to the DBMS, it will never be restored. Current version 3.3.3 does not solve this problem.

Check this

Answer 3

I got the same error and resolved using the below template.

var MongoClient = require('mongodb').MongoClient

const client = new MongoClient(uri, {useUnifiedTopology: true});

client.connect().then((client)=>{
    var db = client.db('db_name')
    db.collection('collection_name').find().toArray(function (err, result) {
        if (err) throw err
        console.log(result);
    })
})

This worked for me. and now it's not showing any DepricationWarning.

Answer 4

I want to add to this thread that it may also have to do with other dependencies.

For instance, nothing I updated or set for NodeJS, MongoDB or Mongoose were the issue - however - connect-mongodb-session had been updated and starting slinging the same error. The solution, in this case, was to simply rollback the version of connect-mongodb-session from version 2.3.0 to 2.2.0.

UPDATE: The issue is now fixed in [email protected].

Answer 5

This is what made it work for me.

MongoClient.connect('mongodb://localhost:27017/blogdb', {useUnifiedTopology: true} , (err, client) =>
{
  if (err) throw err;
  const db = client.db('blogdb');
  const collection = db.collection('posts');
  const users = db.collection('users');
  app.locals.collection = collection;
  app.locals.users = users;

});

This is the same exact code I had before where I was getting the same deprecation message. The only difference is I haven't added the 'useUnifiedTopology: true' line.

MongoClient.connect('mongodb://localhost:27017/blogdb', (err, client) =>
{
  if (err) throw err;
  const db = client.db('blogdb');
  const collection = db.collection('posts');
  const users = db.collection('users');
  app.locals.collection = collection;
  app.locals.users = users;

});

Answer 6

Replace yourdbname with your variable or just link of your mongodb..

 mongoose.connect(yourdbname, {useUnifiedTopology: true, useNewUrlParser: true, useCreateIndex: true })
  .then(console.log("mongodb connected successfully...."))
  .catch(err =>console.log(err));