n8n Notification Listener

This notification listener app acts as a bridge between your Android device's notifications and n8n automation workflows. It captures notifications from specified apps, applies configurable filtering rules, and sends the notification data to designated webhook endpoints. When network issues occur, notifications are stored locally and can be retried manually.

Features

• Captures notifications as they appear
• Rule-based filtering by package name, title regex, and text regex
• Sends structured JSON data to webhook endpoints
• Manual retry for failed or undecided notifications

Technical Architecture

Core Components

graph TD
    A[Application Layer<br/>NotificationListenerApplication] --> B[UI Layer<br/>MainActivity + NotificationListActivity]
    B --> C[Service Layer<br/>NotificationListenerService]
    C --> D[Repository Layer<br/>NotificationRepository]
    D --> E[Network Layer<br/>WebhookApi]
    D --> F[Database Layer<br/>AppDatabase]

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Data Flow

flowchart TD
    A[Android System Notification] --> B[NotificationListenerService.onNotificationPosted]
    B --> C[NotificationDataExtractor.extractNotificationData]
    C --> D[NotificationFilterEngine.isIgnored]

    D --> E{Is Ignored?}
    E -->|Yes| F[Skip Notification]
    E -->|No| G[NotificationFilterEngine.findMatchingUrls]

    G --> H{Has Matching URLs?}
    H -->|No| I[Store as Undecided Notification]
    H -->|Yes| J[Send to Webhook URLs]

    J --> K{Send Successful?}
    K -->|Yes| L[Continue Processing]
    K -->|No| M[Store as Failed Notification]

    I --> N[Available for Manual Upload]
    M --> O[Available for Retry]

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JSON Payload Format

Notifications are sent to webhooks as JSON with the following structure:

{
  "packageName": "com.example.app",
  "title": "Notification Title",
  "text": "Notification content text",
  "timestamp": 1234567890123,
  "id": 12345,
  "tag": "notification_tag"
}

Installation & Setup

1. Build the APK:

./gradlew assembleDebug

2. Install on device (Android 15+):

adb install app/build/outputs/apk/debug/app-debug.apk

3. Grant Notification Access:

• Open the app
• Tap "Enable Notification Access"
• Grant permission in Android settings
• Return to app to verify permission status

Development

Project Structure

app/src/main/java/com/daohoangson/n8n/notificationlistener/
├── MainActivity.kt                 # Main UI
├── NotificationListenerService.kt  # Core service
├── config/
│   ├── WebhookConfig.kt            # Webhook configuration
│   └── NotificationFilterEngine.kt # Filtering logic
├── data/                           # Room database
├── network/                        # Retrofit API
├── ui/                             # Compose UI components
└── utils/                          # Utilities

Testing

The project includes comprehensive unit tests:

./gradlew test