Notification Service

A Node.js microservice for queuing and processing notifications (email, SMS, in-app) using RabbitMQ and MongoDB.

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Features

• Queue notifications via REST API.
• Batch or single notification support.
• Priority & category determined by message content.
• RabbitMQ for async messaging.
• MongoDB for persistent storage.
• Extensible: Add new notification types easily.

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API Endpoints :

1. user/resgister : Register a new user.
2. user/:username : Get user profile info by username.
3. user/:username/notifications : Retrieve all notifications for a given user.
4. /notifications : Queue one or more notifications for processing (single or batch).

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Setup Instructions (Without Docker)

1. Prerequisites

Install and run the following:

• MongoDB

  • Download MongoDB
  • Installation Docs

• RabbitMQ

  • Download RabbitMQ

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2. Clone the Repository

git clone https://github.com/your-username/notification-service.git
cd notification-service

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3. Install Dependencies

npm install

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4. Setup Environment Variables

Create a .env file in the root with the following:

# MongoDB connection string (required)
CONNECTION_STRING=mongodb://localhost:27812/Notification-Service 

# RabbitMQ connection string (required)
RABBITMQ_URL=amqp://localhost

# Application port (optional)
PORT=4001

5. Start the Server

Development mode (auto-restarts with nodemon)

npm run dev

Production mode

node index.js

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6. Start the Consumer Worker

In a separate terminal:

Development mode (auto-restarts with nodemon)

npm run rabbitmq

Production mode

node worker/consumer.js

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API Endpoint

POST /notification

Queue one or more notifications.

Single Notification Example:

{
  "username": "arup04",
  "type": "email",
  "message": "Your OTP is 123456"
}

Batch Notification Example:

[
  { "username": "arup04", "type": "in-app", "message": "You got a like!" },
  { "username": "arup04", "type": "sms", "message": "Your balance is low." }
]

Response:

{
  "message": "Notifications processed",
  "results": [
    {
      "success": true,
      "queue": "notification_in-app",
      "username": "arup04",
      "type": "in-app"
    },
    {
      "success": true,
      "queue": "notification_sms",
      "username": "arup04",
      "type": "sms"
    }
  ]
}

Notes:

• type must be one of: email, sms, in-app
• Each notification must include: username, type, message

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Priority Rules

Notification priority is auto-detected based on keywords in the message:

Keyword(s)	Priority	Level
otp, verify, code	1	High
payment, bill, txn	2	Medium
Anything else	3	Low

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.env Example

# MongoDB
CONNECTION_STRING=mongodb://localhost:27017/notificationdb

# RabbitMQ
RABBITMQ_URL=amqp://localhost

# Optional server port
PORT=4001

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Project Structure

├── config/
│   └── dbconnection.js
├── controller/
│   ├── notificationController.js
│   └── userController.js
├── middleware/
│   └── errorHandler.js
├── routes/
│   ├── notificationRoutes.js
│   └── userRoutes.js
├── schema/
│   ├── notificationSchema.js
│   └── userSchema.js
├── utils/
│   └── rabbitmq.js
├── worker/
│   └── consumer.js
├── .gitignore
├── constants.js
├── index.js
├── package-lock.json
├── package.json
└── README.md

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Troubleshooting

• Ensure MongoDB and RabbitMQ are running before starting the app.
• Double-check your .env file values.
• Use tools like Postman or curl to test the API.
• Watch terminal logs for any errors.