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Notifications Module Documentation - EML Backend

1. Introduction​

The Notifications module in EML Backend enables sending alerts, reminders, and automated notifications to users through various channels, such as email, SMS, and WebSockets.

2. Code Structure​

modules/notifications/
├── notifications.module.ts      # Module definition
├── notifications.controller.ts  # HTTP Controller
├── notifications.service.ts     # Notification sending logic
├── notifications.gateway.ts     # WebSockets for real-time notifications
├── notifications.repository.ts  # Database access
├── dto/                         # Data Transfer Objects (DTOs)
│   ├── create-notification.dto.ts
│   ├── update-notification.dto.ts
├── entities/                    # Database models
│   ├── notification.entity.ts

3. Available Endpoints​

3.1 Create a Notification​

POST /notifications/create - Schedules a new notification.

Request Example:​

curl -X POST http://localhost:3000/notifications/create      -H "Content-Type: application/json"      -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5c..."      -d '{"userId": "12345", "type": "email", "message": "Your appointment is tomorrow at 10 AM"}'

Response Example:​

{
  "notificationId": "notif_abc123",
  "userId": "12345",
  "type": "email",
  "message": "Your appointment is tomorrow at 10 AM",
  "status": "scheduled"
}

3.2 Get Pending Notifications​

GET /notifications/pending - Lists scheduled but not yet sent notifications.

Request Example:​

curl -X GET http://localhost:3000/notifications/pending      -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5c..."

Response Example:​

[
  {
    "notificationId": "notif_abc123",
    "userId": "12345",
    "type": "email",
    "message": "Your appointment is tomorrow at 10 AM",
    "status": "scheduled"
  }
]

3.3 WebSockets: Real-Time Notifications​

The module allows sending real-time notifications using WebSockets.

Example WebSockets Connection:​

const socket = io('http://localhost:3000');
socket.on('connect', () => {
  console.log('Connected to the notifications server');
});
socket.on('newNotification', (data) => {
  console.log('New notification received:', data);
});

4. Security and Middleware​

  • JWT Authentication: All requests require a valid JWT token.
  • Notification Filtering: Ensures users receive only relevant notifications.
  • Priority Rules: Manages priority for urgent alerts.

Example of middleware for protection:

@UseGuards(AuthGuard('jwt'))
@Post('create')
async createNotification(@Body() notificationDto: CreateNotificationDto) {
  return this.notificationService.create(notificationDto);
}

5. Dependencies with Other Modules​

  • Users: To identify recipients.
  • Messages: To manage notifications derived from sent messages.
  • Reports: To generate metrics on notification delivery and reception.

6. Additional Notes​

  • Plans to implement integration with WhatsApp and Push Notifications.
  • Considering integration with email providers such as SendGrid or Mailgun.

7. Conclusion​

The Notifications module in EML Backend enables the automation of alerts across multiple channels, ensuring effective communication with users.

🚀 This document will be updated as the system evolves.