cannot connect to mongo local DB from Node JS

Question

I am learning Mongo DB, Mongoose and Node JS and I can't seem to connect my Node JS to local Mongo DB.

Here is my code:

dbtest.js

    var express  = require('express');
    var app      = express();                               // create our app w/ express
    var mongoose = require('mongoose');                     // mongoose for mongodb
    var morgan = require('morgan');             // log requests to the console (express4)
    var bodyParser = require('body-parser');    // pull information from HTML POST (express4)
    var methodOverride = require('method-override'); // simulate DELETE and PUT (express4)

    var options = {
          useMongoClient: true,
          autoIndex: false, // Don't build indexes
          reconnectTries: Number.MAX_VALUE, // Never stop trying to reconnect
          reconnectInterval: 500, // Reconnect every 500ms
          poolSize: 10, // Maintain up to 10 socket connections
          // If not connected, return errors immediately rather than waiting for reconnect
          bufferMaxEntries: 0
};



    var Todo = mongoose.model('Todo', {
        text : String
    }, 'test');

    var status = {
    "status": "not connected"
    };

    app.get('/api/todos', function(req, res) {

            mongoose.connect('mongodb://127.0.0.1:27017/exampleDB',options,function(err)
    {
              if (err) {
              res.json(status);
            } else {
                res.json('Connected');
            }    
    });  
    });

    app.listen(8080);
    console.log("App listening on port 8080");

When I call api/todos GET request, the status JSON object is returned, meaning I cannot connect to the database.

I installed MongoDB Enterprise Server 3.14.10 completely and have it running but I don't know why my NodeJS application cannot connect.

Any suggestions are appreciated.

Then res.json({ err }) instead of your res.json(status) and actually look at what the error is. — Neil Lunn
– Neil Lunn, Commented Nov 9, 2017 at 5:38
This is the error after the code change as per your comment: {"err":{"state":2}} — Joseph
– Joseph, Commented Nov 9, 2017 at 6:01
Add in console.log(err) and that output will show on the console. Paste the "text" ( NOT a screenshot ) into your question. There will be more detail than what you are telling anyone. — Neil Lunn
– Neil Lunn, Commented Nov 9, 2017 at 6:04
Message is: "Error: Trying to open an unclosed connection." then lots of stack traces. — Joseph
– Joseph, Commented Nov 9, 2017 at 7:37

wscourge · Accepted Answer · 2017-11-09 05:32:58Z

1

Your first mongoose.connect() argument lacks username / password combination:

mongoose.connect('mongodb://username:[email protected]:27017/exampleDB');

answered Nov 9, 2017 at 5:32

wscourge

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1 Comment

Joseph Over a year ago

I can actually connect to MongoDB compass without supplying a username and password so I wonder what can be wrong here.

Jomy Joseph · Accepted Answer · 2017-11-09 06:15:34Z

0

Try to connect db first before doing any action. Once it connected try to use inside your custom function. Below code will helps you to test local database

const express = require('express');
const app = express();
const port = 3000;
const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/dbname', { useMongoClient: true });
mongoose.connection.on('connected', () => {
  console.log('Connected to database ');
}); 
mongoose.connection.on('error', (err) => {
  console.log('Database error: '+err);
});


// Start Server
app.listen(port, () => {
  console.log('Server started on port '+port);
});

Check your cmd window to see console.

answered Nov 9, 2017 at 6:15

Jomy Joseph

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2 Comments

Jomy Joseph Over a year ago

For local database MongoDB compass will accept without username and password by default with default port; FOr other data base you have to provide

Joseph Over a year ago

tried your code in a separate js file, but it only returned me the Server started log. No log on 'connected' or 'error'.

Maxime Ancelin · Accepted Answer · 2020-05-29 07:39:02Z

0

For connecting to a local mongodb, you can use this URI, replacing USER, PASSWORD are DB with your values :

mongodb://USER:[email protected]/DB?authSource=admin

You don't need to provide the port 27017, because it's the default one for mongodb.

The trick here is to add with 'authSource=admin' for enabling the authentication.

Documentation : https://docs.mongodb.com/manual/reference/connection-string/#examples

answered May 29, 2020 at 7:39

Maxime Ancelin

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