How do I setup MongoDB database on Heroku with MongoLab?

Question

I'm using Express.js and MongoLab and I followed the Heroku setup to get MongoDB working in production throwing this code in my app.js.

//Mongo on Heroku Setup
var mongo = require('mongodb');

var mongoUri = process.env.MONGOLAB_URI || 
  process.env.MONGOHQ_URL || 
  'mongodb://localhost/mydb'; 

mongo.Db.connect(mongoUri, function (err, db) {
  db.collection('mydocs', function(er, collection) {
    collection.insert({'mykey': 'myvalue'}, {safe: true}, function(er,rs) {
    });
  });
});

and I have the following routes and field for my email form (also in app.js):

//Routes

app.get('/', function(req, res) {
    res.render('index', {
        title: 'DumbyApp'
    });
});

//save new email
app.post('/', function(req, res){
    emailProvider.save({
        address: req.param('address')
    }, function( error, docs) {
        res.redirect('/')
    });
});

This renders the new form on the index page and lets me save it locally but not in production because I don't know how to setup my email collection. Can anyone walk me through this? brand new to using MongoDB and Node.js, so could use some help.

EDIT:

In The MongoLab Database Interface, I made a collection called emails. Is this the right course of action?

EDIT 2:

Here's defining EmailProvider in app.js along with the file itself.

app.js

 var express = require('express')
  , routes = require('./routes')
  , user = require('./routes/user')
  , http = require('http')
  , path = require('path')
  , EmailProvider = require('./emailprovider').EmailProvider;

var emailProvider= new EmailProvider('localhost', 27017);

emailprovider.js

var Db = require('mongodb').Db;
var Connection = require('mongodb').Connection;
var Server = require('mongodb').Server;
var BSON = require('mongodb').BSON;
var ObjectID = require('mongodb').ObjectID;

EmailProvider = function(host, port) {
  this.db= new Db('localdb', new Server(host, port, {safe: false}, {auto_reconnect: true}, {}));
  this.db.open(function(){});
};


EmailProvider.prototype.getCollection= function(callback) {
  this.db.collection('emails', function(error, email_collection) {
    if( error ) callback(error);
    else callback(null, email_collection);
  });
};

//save new email
EmailProvider.prototype.save = function(emails, callback) {
    this.getCollection(function(error, email_collection) {
      if( error ) callback(error)
      else {
        if( typeof(emails.address)=="undefined")
          emails = [emails];

        for( var i =0;i< emails.address;i++ ) {
          email = emails[i];
          email.created_at = new Date();
        }

        email_collection.insert(emails, function() {
          callback(null, emails);
        });
      }
    });
};

exports.EmailProvider = EmailProvider;

Answer 1

While the connection code in the first code box appears to be correct, the emailProvider object isn't using it. Instead, in app.js, the EmailProvider is being connected to localhost:27017 and the database name is hardcoded in emailprovider.js as 'localdb'.

What you want to do instead is use the connection information provided in the MONGOLAB_URI environment variable in your EmailProvider, which contains the host, port, and database name already.

There are a number of ways to go about doing this, but one way would be to move your connection code from that first code box into the EmailProvider constructor, and then change the constructor so that it takes a URI instead of a host and port. That way, you can pass the MONGOLAB_URI variable to the constructor in app.js.