Tweetaspike

The purpose of this sample application is to show that Aerospike APIs on top of a key-value store are an effective way to write applications with Aerospike as the only database. To demonstrate, this sample app describes the design and implementation of a "twitter-like" application called Tweetaspike.

The code is easy to follow and substantial enough to be a foundation in learning how to leverage Aerospike's technology and it can also be used as a "seed" application that you can expand.

This application is built using -- Aerospike + Express + Angular + Node -- ASEAN (/a-shawn/) Stack :)

Application Features Overview

• Register | Login | Logout
• Tweet — post new tweets
• Follow — follow other users
• Unfollow — unfollow users you are following
• Following — list of users you follow including their posts
• Followers — list of users that follow you including their posts
• Alerts — real-time alerts when users you are following add new posts

Aerospike's Open Source Technologies Used

• Aerospike Server
• Aerospike Node.js Client

Other Technologies Used

• Node.js
• AngularJS
• Express
• Socket.io
• Angular UI

Get Up and Running

Compatibility

• OS:
  • CentOS/RHEL 6.x, Debian 6+, Ubuntu 12.04, Ubuntu 14.04, Mac OS X (IMP: Aerospike Node.js Client currently does not have support for Windows)
• Mac OS X:
  • 10.8 or greater
  • Xcode 5 or greater
  • Xcode Dev Tools

Prerequisites

• Aerospike Server – To install the latest version, click here. The server should be running and accessible from this app.
• Node.js – To install latest stable version, click here

Note: To easily manage your existing Node.js installations and switch between versions, use version manager such as nvm. To install nvm, visit https://www.npmjs.com/package/nvm. Once installed, you can install different versions of Node.js using command nvm install version or switch to a different version that you already have installed using command nvm use version

Technical Know-How

Even though this is a pretty lightweight application, I’ve used different technologies to make it decent enough – visually & functionally – and covering all aspects as well as walking through the entire codebase is beyond the scope of this README. So, good understanding and working knowledge of the following technologies is presumed.

• Node.js
• AngularJS
• Express
• Socket.io
• Angular UI

Usage

Build

To build the application and resolve dependencies, run command sudo npm update from the application root folder.

Config

In aerospike_config.js, update aerospikeCluster and aerospikeClusterPort such that it points to your instance running Aerospike Server.

Run

To run the application, run command node server from the application root folder.

You should see message Connection to Aerospike cluster succeeded!

If you see Connection to Aerospike cluster failed!, please make sure your instance of Aerospike Server is running and available. Also confirm that aerospikeCluster and aerospikeClusterPort are set correctly as described above in the Config section.

If all is well, open web browser and point it to: http://localhost:9000

Updating Styles

In a different terminal window, browse to the application root folder. Then run command grunt — and keep it running while you are updating app.scss or main.scss. This will compile your updates in .scss files and generate respective .css files in real-time.

Additional Information

Data Models

Users

Stores one user record per User.

Key: uid

Bins:

• uid - String
• username - String
• password - String
• auth - String
• tweetCount - Integer

Sample Record:

{ ns: 'test', set: 'users', key: 'dash' } 
{ uid: 'dash',
  username: 'dash',
  password: 'dash',
  auth: 'c18d1b9a-19fb-4b2b-b4d3-560c8af07ef6',
  tweetCount: 3 }

Note: For simplicity, password is stored in plain-text

Tweets

Stores one tweet record per Tweet.

Key: uid:tweetcount

Bins:

• key - String
• username - String
• tweet - String
• ts - Integer

Sample Record:

{ ns: 'test', set: 'tweets', key: 'dash:0' } 
{ key: 'dash:0',
  username: 'dash',
  tweet: 'Put.a.Bird.On.It',
  ts: 1427945664001 }

Note: Key for Tweet record includes tweet counter so you can use Aerospike's Batch operation to retrieve all tweets for a given user with one API call.

Alternate Tweets Data Model

Stores one tweet record per User.

Key: uid

Bin:

• tweets - Map

Sample Record:

{ ns: 'test', set: 'tweets', key: 'dash' } 
{ 1428433280390: 'hello budapest!',
  1428433295094: 'good morning to you all!' }

Note: tweets Map entries would contain key-value pairs; where key is the timestamp and value is the tweet.

Followers

Stores one record per User.

Key: uid

Bin:

• followers - Array of Strings

Sample Record:

{ ns: 'test', set: 'followers', key: 'dash’ } 
{ followers:
   [ 'joe',
     'jane',
     'moe',
     'homer',
     'peter'] }

Following

Stores one record per User.

Key: uid

Bin:

• following - Array of Objects

Sample Record:

{ ns: 'test', set: 'following', key: 'dash' } 
{ following:
   [ { tweets: [], handle: 'claire' },
     { tweets: [], handle: 'brandon' },
     { tweets: [], handle: 'donovan' },
     { tweets: [], handle: 'mary' },
     { tweets: [], handle: 'mike' },
     { tweets: [], handle: 'eva' },
     { tweets: [], handle: 'mark' }] }

Note: The empty tweets array gets populated on-demand in the client when user clicks / wants to see the tweets for a given user.

Application Flow

Register

• Enforces unique usernames
• Requires username and password
• Creates User record

Login

• Check if User record with username key exists * If it does not exist, username entered is invalid * If it exists, check if entered password matches the User record
  • If it does not, password entered is invalid
  • If passwords match:
    • Store auth in HTML5 Web/Local Storage
      • This value is used to check if user is logged in when browsing to various pages within the app. If this value is not found, user is routed back to Login
      • This value is cleared when user Logs out
      • Log user in

New Tweet/Post

• Increments tweet count (tweetCount) by 1 in the User record
• Adds new Tweet record with key <uid>:<tweetCount>

Follow

• Adds new object (tweets/posts array and handle of user-to-follow) to array of objects stored and accessed via uid key for the current user
• Retrieves followers (array accessed via uid key) of user-to-follow user and adds current user as a follower

Unfollow

• Removes object (tweets/posts array and handle of user-to-unfollow) from array of objects stored and accessed via uid key for the current user
• Retrieves followers (array accessed via uid key) of user-to-unfollow user and removes current user as a follower

Following

• Shows a list of users that current user is following
• On initial load, only the list of following users is retrieved using uid key
• The tweets/posts of following users are retrieved on-demand when user clicks on their row

Followers

• Shows a list of users that are following current user
• On initial load, only the list of followers users is retrieved using uid key
• The tweets/posts of followers users are retrieved on-demand when user clicks on their row

Real-time Alerts

• The technology used in this app to deliver real-time alerts is Socket.io
• The app is setup to listen for tweet event -- which is triggered when a new tweet/post gets added by a user. The object sent as a message to Socket.io client emit API looks like {uid: uid, tweet: tweetText}
• Upon receiving a tweet event it then gets emitted out (in our case as a broadcast event) to the connected clients along with data object {uid: uid, tweet: tweetText} it received
• Individual clients are setup to listen on socket:broadcast event emitted as described above -- here the listener loops through users that the current user is following and if one of the users’ uid matches that of the data object it received {uid: uid, tweet: tweetText}, an alert is displayed

Logout

• Clears out auth stored in HTML5 Web/Local Storage and routes the user back to Login