windows - 2-line NodeJS application crashes on mongoose.connect() while trying to connect to a mongolab MongoDB database

Question

I have the following NodeJS code:

var mongoose = require('mongoose');
mongoose.connect('mongodb://dev:dev@ds031632.mongolab.com:31632/mongodev');

And upon running it with node server.js, it hangs up for a few seconds and throws the following:

C:Usersdevworkcodelocal
odejsplayground
estwithmongo
od
dulesmongoose
ode_modulesmongodblibserver.js:228
        process.nextTick(function() { throw err; })
                                            ^
Error
    at Object.<anonymous> (C:Usersdevworkcodelocal
odejsp
round
estwithmongo
ode_modulesmongoose
ode_modulesmongodb
ode_modulesmong
coreliberror.js:42:24)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (C:Usersdevworkcodelocal
odejsp
round
estwithmongo
ode_modulesmongoose
ode_modulesmongodb
ode_modulesmong
coreindex.js:2:17)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)

I pinged the server by console via this:

ping ds031632.mongolab.com

I tried installing mongodb with the windows installer and it's still not working

Answer 1

This error happens when there is an error connecting to mongodb without an error callback to be called. To fix this error (and get the actual error,) add a callback to the .connect method, or, bind to the error event.

mongoose.connect(config.mongodb, function (err) {
  if (err) {
    console.log(err);
  }
});

or

mongoose.connect(config.mongodb);

var db = mongoose.connection;

db.on('error', function (err) {
  console.log('mongodb connection error: %s', err);
  process.exit();
});
db.once('open', function () {
  console.log('Successfully connected to mongodb');
  app.emit('dbopen');
});

---

If you find that nothing happens and it just hangs, wait 30 or so seconds and it will timeout, which simply means mongoose couldn't connect to mongodb, which could be caused by a very large number of different things, mostly related to network/dns/firewall/server configuration.