MongoDB - Error: invalid schema, expected mongodb - node.js

Question

I'm new in building application with MEAN Stack, I'm trying to build a real time chat app, here is my server side :
console.log("Server running...!");
var mongo=require('mongodb').MongoClient;
var client=require('socket.io').listen(8080).sockets;
mongo.connect('localhost:27017/db/chat',function(err,db){
if(err) throw err;
client.on('connection',function(socket){
console.log('someone has connected !');
//waiting for input
socket.on('input',function(data){
console.log(data);
});
});
});
I am sure that i created a data base called chat with mongodb, also mongo is waiting for connection. But when i run the server with node server.js an error occurs :
Server running...!
C:\Users\azus\Desktop\Psirt\codemaster\node_modules\ mongodb\lib\url_parser.js:20
throw new Error('invalid schema, expected mongodb');
^
Error: invalid schema, expected mongodb
at module.exports (C:\Users\azus\Desktop\Psirt\code-master\node_modules\mong
odb\lib\url_parser.js:20:11)
at connect (C:\Users\azus\Desktop\Psirt\code-master\node_modules\mongodb\lib
\mongo_client.js:125:16)
at Function.MongoClient.connect (C:\Users\azus\Desktop\Psirt\code-master\nod
e_modules\mongodb\lib\mongo_client.js:109:3)
at Object.<anonymous> (C:\Users\azus\Desktop\Psirt\code-master\server.js:6:8
)
at Module._compile (module.js:413:34)
at Object.Module._extensions..js (module.js:422:10)
at Module.load (module.js:357:32)
at Function.Module._load (module.js:314:12)
at Function.Module.runMain (module.js:447:10)
at startup (node.js:139:18)
C:\Users\azus\Desktop\Psirt\code-master>
I had been blocked at this phase for weeks, could anyone help on this?
Thanks.

Answer 1

This is because you are using the connection string in an improper format.
You are using localhost:27017/db/chat while it should be mongodb://localhost:27017/db/chat
The pattern for the connection string is mongodb://<HOSTNAME>:<PORT>/<DBNAME>
Article for reference: https://mongodb.github.io/node-mongodb-native/api-generated/mongoclient.html#mongoclient-connect

Answer 2

I just had this issue as well and it was because I had the protocol wrong:
mongo://localhost:27017/test
The protocol being wrong can also cause this error. It should be like this:
mongodb://localhost:27017/test

Answer 3

Sometimes, error might be with the quotes around environment variables. Remove them once and try. Might help.
Error might be with :
set DATABASE_URI='mongodb://localhost:1000/my_app' && node index.js
Correct command will be:
set DATABASE_URI=mongodb://localhost:1000/my_app && node index.js

Answer 4

Try this, it works:
mongoose.connect('mongodb://localhost:27017/shopping');

Answer 5

Just figured out the same problem. Damned windows save quotes in environment.
So if you use windows and wrote this way SET MONGO_URL="mongodb://localhost:27017/{name of your db}" It is not correct.
Correct way is SET MONGO_URL=mongodb://localhost:27017/{name of your db} without quotes.
Also i discovered that you must write protocol exactly - mongodb.
There is code what check the protocol from file url_parser.js
var result = parser.parse(url, true);
if(result.protocol != 'mongodb:') {
throw new Error('invalid schema, expected mongodb');
}

Answer 6

the working code would be like this
don't forget to replace username, password & URL
const socketClient = require('socket.io').listen(4000).sockets;
const MongoClient = require('mongodb').MongoClient;
const uri = "mongodb+srv://<username>:<password>#cluster0-saugt.mongodb.net/test?retryWrites=true&w=majority";
const client = new MongoClient(uri, { useNewUrlParser: true });
client.connect(err => {
socketClient.on('connection', function (socket) {
//Need to Get the Database first before trying to access the collections.
let chat = client.db("test").collection('chats');
// Get chats from mongo collection
// perform actions on the collection object
chat.find().limit(100).sort({ _id: 1 }).toArray(function (err, res) {
if (err) {
throw err;
}
// Emit the messages
socket.emit('output', res);
});
});
});

Answer 7

Might seem obvious, but you'll also encounter this error when you pass invalid values in general to the mongo client, e.g. undefined. Ran into this when I was referencing the wrong key on a config object.

Answer 8

Change content of this line from
mongo.connect('localhost:27017/db/chat',function(err,db)
to
mongo.connect('mongodb://localhost:27017/db/chat',function(err,db)
Then you can connect MongoDB database successfully.

Answer 9

update your mongodb npm version