This code demonstrates how to use ExpressJS Node Framework with MongoDB on Heroku

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In terminal run the following commands in this directory to create the Git repository

git init
git add .
git commit -am "init commit"

.gitignore

Create .gitignore file. Place the following text into the file and save.

node_modules
.env

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Install Node Module Dependencies

Install all the Node dependencies listed in package.json run the following command in Terminal

npm install

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To deploy to Heroku and use the Heroku Add-on services we need to have an App created. Follow the instructions here http://devcenter.heroku.com/articles/node-js

• Install Heroku toolbelt if you do not already have it installed

• Create a new App on Heroku with the following command

  heroku create --stack cedar

This creates a new App on Heroku and adds a remote path to your Git repository.

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Add and configure MongoLabs

Add the MongoLabs add-ons

To add MongoLabs as your MongoDB provider run the following command in terminal. This will add the free starter plan MongoLabs offers to Heroku users. Be sure you have verified your Heroku account http://www.heroku.com/verify

heroku addons:add mongolab:starter

Next, we need to get the username, password and database URI that MongoLabs has supplied us. Heroku keeps this in the a configuration file. Run the following,

heroku config | grep MONGOLAB_URI

This will return your MongoLabs connection string

MONGOLAB_URI => mongodb://username:password@host:port/database

Create environment configuration file

We need to create a new file name .env this will hold the MongoLabs information. This will allow you to use the Environment variables in your code, this is good for keeping your username and password out of your code.

Copy the string from the previous Terminal command, copy all text after => . It should look similar to this,

mongodb://username:password@host:port/database

In your .env file, create a variable for MONGOLAB_URI= append it with the string you copied

MONGOLAB_URI=mongodb://username:password@host:port/database

Save the file.

You can access environment variables in your NodeJS code, for example in web.js as follows,

process.env.MONGOLAB_URI // this is the same as manually entering 'mongodb://username:password@host:port/database'

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Mongoose - MongoDB node module

We will be using Mongoose library to connect to our database. Update your web.js file to include Mongoose module and database configuration.

web.js

var express = require('express'); 
var ejs = require('ejs'); //embedded javascript template engine

var app = express.createServer(express.logger());

var mongoose = require('mongoose'); // include Mongoose MongoDB library
var schema = mongoose.Schema; 

/************ DATABASE CONFIGURATION **********/
app.db = mongoose.connect(process.env.MONGOLAB_URI); //connect to the mongolabs database - local server uses .env file

// include the database model / schema
require('./models').configureSchema(schema, mongoose);

// Define your DB Model variables
var BlogPost = mongoose.model('BlogPost');
var Comment = mongoose.model('Comment');
/************* END DATABASE CONFIGURATION *********/

Models and Schema - models.js

There is a new file called models.js, this includes the data definitions or schema for your database. You will define what data you will be saving in your Mongo collection. See the Mongoose web site for more information, http://mongoosejs.com/