v2.1.2: Slack alert if wp_mail_failed

- fix #25: Webhook field to use for hook

Author: lsthompson

CHANGELOG.md

@@ -1,6 +1,14 @@
 # Changelog
 All notable changes to TNC Toolbox for WordPress will be documented in this file.
 
+## [2.1.2] - 2026-01-13
+
+### 🚀 Feature
+- **Slack Alerts for Mail Failures**: Receive Slack notifications when `wp_mail` fails
+  - New "Slack Webhook URL" field in plugin settings
+  - Alerts include site name, recipient, subject, and error details
+  - Uses WordPress `wp_mail_failed` hook for reliable detection
+
 ## [2.1.1] - 2026-01-10
 
 ### 🐛 Bug Fix

README.md

@@ -13,6 +13,7 @@ https://wordpress.org/plugins/tnc-toolbox
 - For any action, redirects you back to the page you requested it from
 - Shows you whether or not the API is working via diagnostic quota info
 - Selective cache purging with `ea-nginx-cache-purge` module (optional)
+- Slack alert (via Webhook) if WordPress fails to send an email to you
 
 ## 🖥️ (PLUGIN) System Requirements
 

tnc-toolbox/core/settings.php

@@ -50,6 +50,7 @@ public function __construct() {
         $this->plugin_name = TNCTOOLBOX_NAME;
         add_action('init', array($this, 'init_settings'));
         add_action('admin_enqueue_scripts', array($this, 'enqueue_admin_styles'));
+        add_action('wp_ajax_tnc_test_slack_webhook', array($this, 'ajax_test_slack_webhook'));
     }
 
     // Enqueue admin styles for settings page
@@ -126,11 +127,15 @@ private function save_settings() {
         $api_key = sanitize_text_field($_POST['tnc_toolbox_api_key'] ?? '');
         $username = sanitize_text_field($_POST['tnc_toolbox_username'] ?? '');
         $hostname = sanitize_text_field($_POST['tnc_toolbox_server_hostname'] ?? '');
+        $slack_webhook = sanitize_url($_POST['tnc_toolbox_slack_webhook'] ?? '');
 
         // Handle selective purge setting - use the POST value directly to avoid race conditions
         $selective_purge_enabled = isset($_POST['tnc_selective_purge']);
         TNC_Cache_Purge::set_enabled($selective_purge_enabled);
 
+        // Save Slack webhook URL
+        TNC_Slack_Alerts::store_webhook_url($slack_webhook);
+
         // Try to save the configuration even if empty to ensure options exist
         TNC_cPanel_UAPI::store_config($username, $api_key, $hostname);
 
@@ -229,6 +234,21 @@ class="regular-text" />
                                 </label>
                             </td>
                         </tr>
+                        <tr>
+                            <th scope="row">
+                                <label for="tnc_toolbox_slack_webhook">Slack Webhook URL</label>
+                                <p class="description">For mail failure alerts.<br><a href="https://api.slack.com/messaging/webhooks" target="_blank">Create Webhook</a>.</p>
+                            </th>
+                            <td>
+                                <input type="url" id="tnc_toolbox_slack_webhook" name="tnc_toolbox_slack_webhook"
+                                    value="<?php echo esc_attr(TNC_Slack_Alerts::get_webhook_url()); ?>"
+                                    placeholder="https://hooks.slack.com/services/..."
+                                    class="regular-text" />
+                                <button type="button" id="tnc_test_slack_webhook" class="button button-secondary">Test Webhook</button>
+                                <span id="tnc_slack_test_result" style="margin-left: 10px;"></span>
+                                <p class="description">Receive alerts when WordPress fails to send emails.</p>
+                            </td>
+                        </tr>
                     </table>
 
                     <p class="submit">
@@ -254,6 +274,72 @@ class="regular-text" />
                 <?php endif; ?>
             </div>
         </div>
+        <script type="text/javascript">
+        jQuery(document).ready(function($) {
+            $('#tnc_test_slack_webhook').on('click', function() {
+                var $button = $(this);
+                var $result = $('#tnc_slack_test_result');
+                var webhookUrl = $('#tnc_toolbox_slack_webhook').val();
+                
+                if (!webhookUrl) {
+                    $result.html('<span style="color: #dc3232;">Please enter a webhook URL first.</span>');
+                    return;
+                }
+                
+                $button.prop('disabled', true).text('Testing...');
+                $result.html('');
+                
+                $.post(ajaxurl, {
+                    action: 'tnc_test_slack_webhook',
+                    webhook_url: webhookUrl,
+                    nonce: '<?php echo wp_create_nonce('tnc_test_slack_webhook'); ?>'
+                }, function(response) {
+                    if (response.success) {
+                        $result.html('<span style="color: #46b450;">✓ ' + response.data.message + '</span>');
+                    } else {
+                        $result.html('<span style="color: #dc3232;">✗ ' + response.data.message + '</span>');
+                    }
+                }).fail(function() {
+                    $result.html('<span style="color: #dc3232;">✗ Request failed</span>');
+                }).always(function() {
+                    $button.prop('disabled', false).text('Test Webhook');
+                });
+            });
+        });
+        </script>
         <?php
     }
+
+    /**
+     * AJAX handler for testing Slack webhook
+     */
+    public function ajax_test_slack_webhook() {
+        // Verify nonce
+        if (!wp_verify_nonce($_POST['nonce'] ?? '', 'tnc_test_slack_webhook')) {
+            wp_send_json_error(array('message' => 'Invalid nonce'));
+        }
+
+        // Check permissions
+        if (!current_user_can('manage_options')) {
+            wp_send_json_error(array('message' => 'Permission denied'));
+        }
+
+        // Get and validate webhook URL
+        $webhook_url = sanitize_url($_POST['webhook_url'] ?? '');
+        if (empty($webhook_url)) {
+            wp_send_json_error(array('message' => 'No webhook URL provided'));
+        }
+
+        // Temporarily store the URL for testing
+        TNC_Slack_Alerts::store_webhook_url($webhook_url);
+
+        // Run the test
+        $result = TNC_Slack_Alerts::test_webhook();
+
+        if ($result['success']) {
+            wp_send_json_success(array('message' => $result['message']));
+        } else {
+            wp_send_json_error(array('message' => $result['message']));
+        }
+    }
 }

tnc-toolbox/readme.txt

@@ -5,7 +5,7 @@ Donate link:
 Contributors:
 Tags: NGINX, Cache Purge, Web Performance, Automatic Purge, Freeware
 Tested up to: 6.9
-Stable tag: 2.1.1
+Stable tag: 2.1.2
 License: GPLv3
 License URI: https://www.gnu.org/licenses/gpl-3.0.html
 
@@ -152,6 +152,9 @@ _(* Change to main plugin file name may result in deactivation)_
 
 == Changelog ==
 
+= 2.1.2: Jan 13, 2026 =
+* Feature: Slack alerts when wp_mail fails (Webhook field)
+
 = 2.1.1: Jan 10, 2026 =
 * Bug Fix: Fix false positive cache-purge module detection
 

tnc-toolbox/tnc-toolbox.php

@@ -5,13 +5,13 @@
  * @package           TNCTOOLBOX
  * @author            The Network Crew Pty Ltd (Merlot Digital)
  * @license           gplv3
- * @version           2.1.1
+ * @version           2.1.2
  *
  * @wordpress-plugin
  * Plugin Name:       TNC Toolbox: Web Performance
  * Plugin URI:        https://merlot.digital
  * Description:       Designed for ea-NGINX (Cache/Proxy) on cPanel+WHM. Now with selective cache purging support!
- * Version:           2.1.1
+ * Version:           2.1.2
  * Author:            The Network Crew Pty Ltd (Merlot Digital)
  * Author URI:        https://tnc.works
  * Domain Path:       /locale
@@ -29,7 +29,7 @@
 define('TNCTOOLBOX_NAME', 'TNC Toolbox');
 
 // Plugin version
-define('TNCTOOLBOX_VERSION', '2.1.0');
+define('TNCTOOLBOX_VERSION', '2.1.2');
 
 // Plugin Root File
 define('TNCTOOLBOX_PLUGIN_FILE', __FILE__);
@@ -48,6 +48,7 @@
 require_once TNCTOOLBOX_PLUGIN_DIR . 'core/settings.php';
 require_once TNCTOOLBOX_PLUGIN_DIR . 'vendor/cpanel-uapi.php';
 require_once TNCTOOLBOX_PLUGIN_DIR . 'vendor/cache-purge.php';
+require_once TNCTOOLBOX_PLUGIN_DIR . 'vendor/alerts-slack.php';
 
 /**
  * Main plugin class for initialisation and hooks