Alafazam / event-notification-system

A demo notification system

demo

A notification system to notify subscribers of changes made in a mongodb database in real-time.

Why did, I did what I did.

I was a was a bit confused between two approaches, 1. using plain HTTP requests only (for notifications: pinging /notifications every 2-3 seconds + for subscription: using HTTP verbs for subscribing and subscribing to items) and 2. Using socketIO (for notifications: emitting 'notifications' from server side on each change + for subscription: emitting subscribe/unsubscribe to events). In 1st approach, notifications part was not good and in 2nd approach subscription part. So I went into crazy mode and combined both of these. Now for notifications, I have used Socket.IO + node.js-EventEmmiters to notify user (based on their subscriptions) about db changes in real time. For subscriptions, I have made a REST-full api that front end calls for subscribing/unsubscribing.

I have also made another API for making changes to database. So on one end we can send request to database for adding,updating and deleting item. And on other end some client connected to /getting_started will receive notifications about these. Sure these two could have been separate, but connecting these two solved the SocketIO-vs-HTTP-only confusion like a boss.

I have used materialize.css for front end because my front end skills are no match for that beautiful library.

API Usage

/api/items GET Get all items in database. POST key: name value:- nameforItem eg G.O.T Creates a new Item in database.

api/items/:name GET Get item with name in database. PUT Update the Item with name in database. Here we are just updating its last modified time. Can be exteded to update properties. DELETE Get item with name in database.

Now for actual usage

Just go to /getting_statred, select what you want to subscribe to and wait for changes to occur in db. List of Items to subscribe to is generated automatically from db. So to addother item there one must create the item in db.

Endpoints

/subscribe GET Get all subscription items. POST Subscribe to something.

/subscribe/:item_id item_id is Item name GET Tell if your are subscribed to item with item_id in database. PUT subscribe to item with item_id in database. DELETE unsubscribe to item with item_id in database.

/subscribe_all GET subscribe to all items DELETE unsubscribe from all items