Real-Time Notification System micro-service

-Using: Node.js, Mongo Atlas as database, cloudampq (cloud RabbitMQ) as message queueing, mocha.js and chai as testing tools , Postman for http requests and Docker

• A Real time service that receive a post request from a sender to send a notification to different types of providers by using message queuing system.
• Service also provide APIs to access Notifications’ database (MongoDB), database is used for storage not for sending.
• Test cases coverage by using mocha.js and chai
• Application is run on Docker and available on docker hub

Architecture diagram

How to run it (Main idea)

The whole system consists of :

• Main server
• Notification service (our main part)
• MongoDB on Cloud (MongoDB Atlas)
• RabbitMQ ( cloudamqp)
• Simple client side program ( A program which the client runs to get the notification)

In points :

• Main Server / Notification Service Relation :

• Main server makes a post request with Notification body -Notification service responds by “Notification is sent” and continue the process or responds by the error with out sending the notification -Notification service saves the new notification in the cloud database (Only for recording) -Main Server can read the Notifications records through Notification service’s APIs

• Notification Service / Cloud queues / Client Relation :

• There are two separated groups of queues ( Push Notification queues and SMS Notifcation queues ) Why ? To allow front-end layer to consume the notifications from the queue through the “Client-side Progam” to fetch the Notifications in HTML or XML or other options. And also to let a SMS provider to consume the messages by sending it to the clients. Each client has two queue ; a queue for his application and another one for his SMS messages

• Notification service sends the notification to the right queue of the user/s according to the notification target/s and the provider ( Push Notification or SMS Notification)

• Client Program contains a function that push the notifications into an local array

• User can use this array directly to update notification at real-time -Here a question : Why I didn’t use an API to send the messages ? because it will not be a real time notification , every new notification , I need to make a request , may be Main server sends more than one notification between two recursive requests.

How it runs

-The code Architecture

The Main Service (The Notification Publisher)

• Config.env : configuration file that contains the configurations of the Mongoose , CloudAmpq
• Database configuration : Separated file contain the configuration of the database and only export connect function to use it in our application
• pushControllers: All the function I needed when writing the Publish Notifications API.
• Notification model: contains the schema of the notification to use it in saving to database and publishing it to the queue.
• Routes : Notification API route and Accessing the database APIs
• test : test scripts to test our code, tests are separated into 4 types and all of them run together at testing stage.
• app.js : contains requiring the files and libraries , database connecting function firing , listening to the port and using the routes to be able accessing it

The client code (The consumer)

• Config.env : configuration file that contains the configurations of the Mongoose , CloudAmpq
• Client.js : a file containing the code the client needing to receive the notification and exports one function to allow the user receives it
• app.js: user can here use the function with his other pieces of code.

- The code running:

To run the main service :

• On the command line: node app
• Using post request by :(/api/pushNotification) to send a notification
• Using get requests to access database:
  • 1- /notificationDatabase/readAllNotification/allUsers
  • 2- /notificationDatabase/byPhoneNumber/:phoneNumber
  • 3- /notificationDatabase/byLanguage/:language
  • 4- /notificationDatabase/byProvider/:provider
  • 5- /notificationDatabase/notificationContains/:notification
• API’s will be discussed in the next chapter.

  To run tests:

• npm run test ( using mocha.js in package.json as test runner)

How another microservices would contact this service to send a notification (Service APIs)

• Make a post request to send a notification with prober request body
  • /api/pushNotification Method : POST Required body : {
  • message : required
  • provider : required , enum of ["Push Notification", "SMS Notification"] Push is the default
  • target (The phonenumber/s that you want to send the Notification) : at least one
  • isRead : not required (for future improvments for the service)
  • language : enum of [En , Ar ,Fr] not required : En is the default

---

Returns :

• 1- if notification is successfuly sent : it will return Msg is successfuly statusCode :( 200)

• Errors :

  • No targets : "No targets are Supported " statusCode :(400 Bad request)
  • No message supported in the Notification : "No message is Supported" (400 Bad request)
  • Other provider : "Notification is not a provided Notification type" statusCode : (400 Bad request)

• 2- Returns all the notifications in the database Method : GET

  • /notificationDatabase/readAllNotification/allUsers 3- Returns all the notifications sent to a phonenumber Method : GET
  • /notificationDatabase/byPhoneNumber/:phoneNumber 4- returns all the notifications by a certain language Method : GET
  • /notificationDatabase/byLanguage/:language 5- returns all the notifications by a certain provider Method : GET
  • /notificationDatabase/byProvider/:provider 6- returns all the notifications that contains a certain string ( example : (essa)------> returns notifications contain : ( message )) Method : GET
  • /notificationDatabase/notificationContains/:notification

Important Note:

• The server doesn't need to modify or delete a Notification from the database.
  • Why?
  • Database here is only a recording storage, Server will need only to create or read the database. Creation is only needed when sending a Notification (Push Notification Routes). So here, we make APIs for only reading from the database

Test Cases:

• Home routes test :
  • GET request to main route “/”
  • Wrong GET request to non-supported path
• Notification API (Request Success):
  • 1- All the notification body is provided (one target)
  • 2- All the notification body is provided (many targets)
  • 3- Default values is not provided
  • 4- Default values is not provided (many targets)
• Notification API (Request failure):
  • 1- Message is not provided
  • 2- Message is not provided (many targets)
  • 3- No targets in the notification body
  • 4- Unknown provider is provided 5- No notification is supported in the post request
• Database APIs:
  • 1- Getting all the users
  • 2- Getting Notifications with specific language
  • 3- Getting Notifications with specific phone number
  • 4- Getting Notifications with specific provider
  • 5- Getting Notifications containing specific string

Docker :

• https://hub.docker.com/u/mohamedashraf24695