Realtime Application with MongoDB and Socket.io

This application shows how to use MongoDB to create a pub/sub based application.

It uses :

• MongoDB Capped Collections and Tailable Cursors
• node.js

Online Tutorial

Step 1 : Capped Collection and Tailable Cursors with node.js

See branch step-01

Installation:

1- Create a new database

use chat

2- Create a Capped Collection

db.createCollection('messages', { capped: true, size: 100000 });

3- Insert a dummy document

db.messages.insert({"type":"init"});

4- Install node modules

npm install

5- Start application

node app

6- Insert new documents in the collection

db.messages.insert({"type":"message", "text":"New message"});

You can see that message is capture by the node application

Step 2 : Adding User Interface with Socket.io

See branch step-02

In this step, the application has been improved to send message to an HTML client using socket.io.

Once you hace checked out the step-02 branch and updated the dependencies npm install :

1- Start the application

node app

2- Open your browser and go to:

http://localhost:3000

3- Insert new messages in the collection

db.messages.insert({"type":"message", "text":"New message pushed in web client"});