---
title: Custom Notification Channels
description: Learn how to add custom notification channels like WhatsApp, SMS, or Telegram to WooNooW
---

# Custom Notification Channels

WooNooW supports custom notification channels through a pluggable architecture. You can extend the notification system to send messages via WhatsApp, SMS, Telegram, or any other service.

## Architecture Overview

The multi-channel notification system consists of three core components:

1. **`ChannelInterface`** - Contract that all channels must implement
2. **`ChannelRegistry`** - Central registry for managing channels
3. **`NotificationManager`** - Sends notifications through registered channels

```mermaid
graph LR
    A[NotificationManager] --> B[ChannelRegistry]
    B --> C[Email Channel]
    B --> D[WhatsApp Channel]
    B --> E[SMS Channel]
    B --> F[Custom Channel]
```

## Creating a Custom Channel

### Step 1: Implement ChannelInterface

Create a class that implements `WooNooW\Core\Notifications\Channels\ChannelInterface`:

```php
<?php
namespace MyPlugin\Channels;

use WooNooW\Core\Notifications\Channels\ChannelInterface;

class WhatsAppChannel implements ChannelInterface {
    
    public function get_id() {
        return 'whatsapp';
    }
    
    public function get_label() {
        return __('WhatsApp', 'my-plugin');
    }
    
    public function is_configured() {
        $api_key = get_option('my_whatsapp_api_key');
        return !empty($api_key);
    }
    
    public function send($event_id, $recipient, $data) {
        // Your sending logic here
        return [
            'success' => true,
            'message' => 'Sent successfully'
        ];
    }
    
    public function get_config_fields() {
        return [
            [
                'id' => 'my_whatsapp_api_key',
                'label' => 'API Key',
                'type' => 'text',
            ],
        ];
    }
}
```

### Step 2: Register Your Channel

Register your channel with the `ChannelRegistry` during plugin initialization:

```php
use WooNooW\Core\Notifications\ChannelRegistry;
use MyPlugin\Channels\WhatsAppChannel;

add_action('init', function() {
    $channel = new WhatsAppChannel();
    ChannelRegistry::register($channel);
});
```

### Step 3: Enable in Settings

Once registered, your channel will be available in the notification settings UI, where users can configure which events should use WhatsApp.

## Interface Reference

### get_id()

Returns a unique identifier for your channel.

```php
public function get_id(): string
```

**Example:**
```php
public function get_id() {
    return 'whatsapp'; // or 'sms', 'telegram', etc.
}
```

### get_label()

Returns a human-readable label for the admin UI.

```php
public function get_label(): string
```

**Example:**
```php
public function get_label() {
    return __('WhatsApp Business', 'my-plugin');
}
```

### is_configured()

Checks if the channel has all required configuration (API keys, credentials, etc.).

```php
public function is_configured(): bool
```

**Example:**
```php
public function is_configured() {
    $api_key = get_option('my_whatsapp_api_key');
    $phone = get_option('my_whatsapp_phone');
    return !empty($api_key) && !empty($phone);
}
```

### send()

Sends a notification through this channel.

```php
public function send(string $event_id, string $recipient, array $data): bool|array
```

**Parameters:**
- `$event_id` - Event identifier (e.g., `'order_completed'`, `'newsletter_confirm'`)
- `$recipient` - Recipient type (`'customer'` or `'staff'`)
- `$data` - Context data including order, user, custom variables

**Returns:**
- `bool` - Simple success/failure
- `array` - Detailed result with `success` and `message` keys

**Example:**
```php
public function send($event_id, $recipient, $data) {
    $phone = $this->get_recipient_phone($recipient, $data);
    $message = $this->build_message($event_id, $data);
    
    $response = wp_remote_post('https://api.provider.com/send', [
        'body' => [
            'to' => $phone,
            'message' => $message,
            'api_key' => get_option('my_api_key'),
        ],
    ]);
    
    if (is_wp_error($response)) {
        return [
            'success' => false,
            'message' => $response->get_error_message(),
        ];
    }
    
    return ['success' => true];
}
```

### get_config_fields()

Returns configuration fields for the admin settings UI (optional).

```php
public function get_config_fields(): array
```

**Field Structure:**
```php
[
    'id' => 'option_name',
    'label' => 'Field Label',
    'type' => 'text|select|textarea',
    'description' => 'Help text',
    'options' => [], // For select fields
    'default' => 'value',
]
```

## Complete Example: WhatsApp Channel

See the reference implementation:  
[WhatsAppChannel.example.php](file:///Users/dwindown/Local%20Sites/woonoow/app/public/wp-content/plugins/woonoow/includes/Core/Notifications/Channels/WhatsAppChannel.example.php)

This example includes:
- ✅ Twilio API integration
- ✅ Phone number extraction from orders/users
- ✅ Message templates for common events
- ✅ Configuration fields for admin settings

## Message Customization

Use filters to customize messages for specific events:

```php
add_filter('woonoow_whatsapp_message_order_completed', function($message, $data) {
    if (isset($data['order'])) {
        $order = $data['order'];
        return sprintf(
            "🎉 Order #%s confirmed! Track here: %s",
            $order->get_order_number(),
            $order->get_view_order_url()
        );
    }
    return $message;
}, 10, 2);
```

## Available Events

Your channel can handle any registered notification event:

| Event | Recipient | Data Available |
|-------|-----------|----------------|
| `order_completed` | customer | `order`, `user_id` |
| `order_cancelled` | customer | `order`, `user_id` |
| `newsletter_confirm` | customer | `email`, `confirmation_url` |
| `newsletter_welcome` | customer | `email`, `user_id` |
| `subscription_expiring` | customer | `subscription`, `user_id` |

See [Event Registry](/hooks/notifications#event-registry) for the complete list.

## Testing Your Channel

```php
// Manual test
use WooNooW\Core\Notifications\NotificationManager;

NotificationManager::send('order_completed', 'whatsapp', [
    'order' => wc_get_order(123),
    'user_id' => 1,
]);
```

## Best Practices

1. **Validate Configuration**: Always check `is_configured()` before attempting to send
2. **Handle Errors Gracefully**: Return detailed error messages for debugging
3. **Log Send Attempts**: Use `do_action()` for tracking/analytics
4. **Support Filtering**: Allow message customization via filters
5. **Rate Limiting**: Consider implementing rate limiting for API calls

## Hooks

### Registration Hook
```php
// Register channels during init
add_action('init', function() {
    ChannelRegistry::register(new MyChannel());
});
```

### Custom Hooks in Your Channel
```php
// Allow logging/tracking
do_action('my_channel_sent', $event_id, $recipient, $result);

// Allow message customization
$message = apply_filters(
    "my_channel_message_{$event_id}", 
    $default_message, 
    $data
);
```

## Troubleshooting

**Channel not appearing in settings?**
- Ensure `ChannelRegistry::register()` is called during `init`
- Check that `get_id()` returns a unique string
- Verify `is_configured()` returns `true`

**Messages not sending?**
- Check notification settings: Marketing > Notifications
- Verify the event has your channel enabled
- Enable debug mode and check logs
- Test `is_configured()` returns true

**API errors?**
- Validate API credentials in settings
- Check API provider status/quotas
- Review error logs for API responses

## Related Documentation

- [Notification System](/core-concepts/notifications)
- [Event Registry](/hooks/notifications#event-registry)
- [Notification Hooks](/hooks/notifications)
