Features¶

The Notification Server module provides comprehensive real-time notification capabilities through integration with an external notification server.

Core Features¶

HTTP Notifications¶

Channel-based message publishing - Send messages to specific channels
Channel creation and management - Create channels with custom access rules
Client ID generation and validation - Manage WebSocket client identities
Notification history retrieval - Get previous messages from channels

WebSocket Support¶

Real-time bidirectional communication - Instant message delivery to connected clients
Channel subscription management - Subscribe/unsubscribe from channels dynamically
Message broadcasting to specific channels - Send messages to all channel subscribers
Client connection management - Handle client authentication and access control

Administration¶

Configuration interface for server settings - Easy setup through Drupal admin interface
Permission-based access control - Control who can configure and use the module
Demo interfaces for testing functionality - Built-in demos for HTTP and WebSocket features

Channel Management¶

Channel Creation¶

Create channels with flexible access control rules:

Creating a Channel with Access Rules

PHP

<?php
use Drupal\notification_server\DTO\ChannelDTO;
use Drupal\notification_server\DTO\ChannelRulesDTO;

$rules = new ChannelRulesDTO(
  allowedClientIds: [$client_id],
  isPublic: false,
  allowedPatterns: ['client.*'],
  maxSubscribers: 100
);

$channel = new ChannelDTO('my_channel', $rules);
$notification_client->createChannel($channel);

Access Control¶

Client-specific access - Grant/revoke access to specific client IDs
Pattern-based access - Use regex patterns for client ID matching
Public channels - Allow unrestricted access when needed
Subscriber limits - Control maximum number of concurrent subscribers

Channel Rules¶

Configure channels with:

allowedClientIds - Array of specific client IDs allowed to access the channel
isPublic - Boolean indicating if the channel is publicly accessible
allowedPatterns - Array of regex patterns for matching allowed client IDs
maxSubscribers - Maximum number of subscribers (0 for unlimited)

Client Management¶

Client ID Generation¶

Generate unique client IDs for WebSocket connections:

Client ID Management

PHP

<?php
// Generate with metadata
$client_id = $notification_client->generateClientId(null, [
  'userAgent' => 'Drupal Client',
  'environment' => 'production',
  'userId' => $user->id()
]);

// Validate existing client ID
$is_valid = $notification_client->validateClientId($client_id);

// Remove client and all associated data
$notification_client->removeClient($client_id);

Client Features¶

Automatic client ID generation - Create unique identifiers for WebSocket connections
Client validation - Verify client ID validity before connections
Metadata support - Store additional information with client IDs
Client cleanup - Remove clients and associated data when no longer needed

Notification Publishing¶

Message Types¶

Support for various message formats:

Different Message Types

PHP

<?php
// Simple string message
$notification_client->publishNotification('channel', 'Hello World');

// Structured data
$notification_client->publishNotification('updates', [
  'type' => 'content_update',
  'message' => 'New article published',
  'data' => [
    'nodeId' => 123,
    'title' => 'Breaking News',
    'author' => 'John Doe'
  ]
]);

// Complex objects
$notification_client->publishNotification('events', $event_object);

Message History¶

Retrieve notification history:

Getting Message History

PHP

<?php
// Get last 10 notifications
$notifications = $notification_client->getNotifications('channel_name');

// Get specific number of notifications
$notifications = $notification_client->getNotifications('channel_name', 25);

WebSocket Integration¶

Real-time Communication¶

Instant message delivery - Messages delivered immediately to connected clients
Bidirectional communication - Clients can send and receive messages
Connection status tracking - Monitor client connection states
Automatic reconnection support - Handle connection drops gracefully

JavaScript Integration¶

WebSocket Client Setup

JavaScript

// Establish WebSocket connection
const websocketUrl = drupalSettings.notificationServer.websocketUrl;
const socket = new WebSocket(`${websocketUrl}?clientId=${clientId}`);

// Handle connection events
socket.onopen = () => console.log('Connected');
socket.onclose = () => console.log('Disconnected');
socket.onerror = (error) => console.error('WebSocket error:', error);

// Handle incoming messages
socket.onmessage = (event) => {
  const data = JSON.parse(event.data);
  if (data.type === 'notification') {
    // Process notification
    handleNotification(data.data);
  }
};

// Subscribe to channels
socket.send(JSON.stringify({
  type: 'subscription',
  action: 'subscribe',
  channel: 'my_channel'
}));

Demo Module Features¶

The optional notification_server_demo module provides:

HTTP Demo Interface¶

Message publishing form - Test sending notifications via HTTP
Channel selection - Choose target channels for messages
Message formatting - Test different message types and structures
Response display - View server responses and success/error states

WebSocket Demo Interface¶

Client connection management - Connect/disconnect WebSocket clients
Channel subscription - Subscribe/unsubscribe from channels dynamically
Real-time message display - View incoming notifications in real-time
Connection status monitoring - Track WebSocket connection state
Message log - History of all received messages

Security Features¶

Security Considerations

Always implement proper security measures when using the notification server in production environments. Never expose sensitive data through public channels.

Access Control¶

Permission-based administration - Control who can configure the module
Channel-level access control - Restrict access to specific channels
Client authentication - Validate client IDs before allowing connections
Pattern-based restrictions - Use regex patterns for flexible access rules

Data Validation¶

Input sanitization - Validate all incoming data
Message size limits - Prevent oversized message payloads
Rate limiting - Control message frequency (server-side)
Connection limits - Restrict maximum concurrent connections

Performance Features¶

Performance Optimization

For optimal performance in production, consider configuring Redis memory limits, implementing connection pooling, and monitoring message throughput patterns.

Efficient Communication¶

WebSocket persistence - Maintain long-lived connections for real-time updates
Message batching - Group multiple notifications when appropriate
Connection pooling - Reuse connections efficiently
Minimal overhead - Lightweight protocol implementation

Scalability¶

Redis-backed storage - Fast data persistence and retrieval
Horizontal scaling - Support multiple notification server instances
Load balancing - Distribute connections across servers
Connection management - Handle thousands of concurrent connections