fix: Resolve OAuth callback 404 error and add debugging features

- Add missing HVAC_CE_PLUGIN_FILE constant for plugin activation hooks
- Implement automatic rewrite rule flushing to prevent 404 errors
- Add admin interface button to manually flush rewrite rules
- Include real-time rewrite rule status indicator in admin
- Add comprehensive OAuth callback debugging and error logging
- Change OAuth flow to use same window instead of popup for better UX
- Add activation hook to ensure rewrite rules are set up properly

The OAuth callback URL /oauth/callback should now work correctly after
WordPress rewrite rules have been flushed on the staging server.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

wordpress-dev/wordpress/wp-content/plugins/hvac-community-events/hvac-community-events.php

@@ -18,6 +18,7 @@ if (!defined('ABSPATH')) {
 
 // Define plugin constants
 define('HVAC_CE_VERSION', '1.0.0');
+define('HVAC_CE_PLUGIN_FILE', __FILE__);
 define('HVAC_CE_PLUGIN_DIR', plugin_dir_path(__FILE__));
 define('HVAC_CE_PLUGIN_URL', plugin_dir_url(__FILE__));
 

wordpress-dev/wordpress/wp-content/plugins/hvac-community-events/includes/admin/class-zoho-admin.php

@@ -23,6 +23,7 @@ class HVAC_Zoho_Admin {
         add_action('wp_ajax_hvac_zoho_test_connection', array($this, 'test_connection'));
         add_action('wp_ajax_hvac_zoho_sync_data', array($this, 'sync_data'));
         add_action('wp_ajax_hvac_zoho_save_credentials', array($this, 'save_credentials'));
+        add_action('wp_ajax_hvac_zoho_flush_rewrite_rules', array($this, 'flush_rewrite_rules_ajax'));
         // Add simple test handler
         add_action('wp_ajax_hvac_zoho_simple_test', array($this, 'simple_test'));
         // Add OAuth callback handler
@@ -30,6 +31,9 @@ class HVAC_Zoho_Admin {
         add_action('init', array($this, 'add_oauth_rewrite_rule'));
         add_action('template_redirect', array($this, 'handle_oauth_template_redirect'));
         add_filter('query_vars', array($this, 'add_oauth_query_vars'));
+        
+        // Ensure rewrite rules are flushed when plugin is activated
+        register_activation_hook(HVAC_CE_PLUGIN_FILE, array($this, 'flush_rewrite_rules_on_activation'));
     }
     
     /**
@@ -191,6 +195,15 @@ class HVAC_Zoho_Admin {
                                 <p class="description">
                                     Use this exact URL in your Zoho OAuth app configuration.
                                     <button type="button" id="copy-redirect-uri" class="button button-small">Copy</button>
+                                    <button type="button" id="flush-rewrite-rules" class="button button-small">Flush Rules</button>
+                                </p>
+                                <?php 
+                                // Debug: Check if rewrite rule exists
+                                $rewrite_rules = get_option('rewrite_rules');
+                                $oauth_rule_exists = isset($rewrite_rules['^oauth/callback/?$']);
+                                ?>
+                                <p class="description" style="color: <?php echo $oauth_rule_exists ? '#46b450' : '#dc3232'; ?>">
+                                    OAuth rewrite rule: <?php echo $oauth_rule_exists ? '✓ Active' : '✗ Missing (click Flush Rules)'; ?>
                                 </p>
                             </td>
                         </tr>
@@ -316,6 +329,28 @@ class HVAC_Zoho_Admin {
                 });
             });
             
+            // Flush rewrite rules
+            $('#flush-rewrite-rules').on('click', function() {
+                var button = $(this);
+                button.prop('disabled', true).text('Flushing...');
+                
+                $.post(ajaxurl, {
+                    action: 'hvac_zoho_flush_rewrite_rules'
+                }, function(response) {
+                    if (response.success) {
+                        button.text('Flushed!').css('color', '#46b450');
+                        setTimeout(function() {
+                            location.reload(); // Reload to update the status
+                        }, 1000);
+                    } else {
+                        button.text('Error').css('color', '#dc3232');
+                        setTimeout(function() {
+                            button.prop('disabled', false).text('Flush Rules').css('color', '');
+                        }, 2000);
+                    }
+                });
+            });
+            
             // Handle credentials form submission
             $('#zoho-credentials-form').on('submit', function(e) {
                 e.preventDefault();
@@ -360,7 +395,8 @@ class HVAC_Zoho_Admin {
                     '&redirect_uri=' + encodeURIComponent(redirectUri) + 
                     '&prompt=consent';
                 
-                window.open(oauthUrl, '_blank');
+                // Open OAuth URL in the same window to handle callback properly
+                window.location.href = oauthUrl;
             });
         });
         </script>
@@ -416,6 +452,30 @@ class HVAC_Zoho_Admin {
         ));
     }
     
+    /**
+     * Flush rewrite rules via AJAX
+     */
+    public function flush_rewrite_rules_ajax() {
+        if (!current_user_can('manage_options')) {
+            wp_send_json_error(array('message' => 'Unauthorized access'));
+            return;
+        }
+        
+        flush_rewrite_rules();
+        
+        wp_send_json_success(array(
+            'message' => 'Rewrite rules flushed successfully'
+        ));
+    }
+    
+    /**
+     * Flush rewrite rules on plugin activation
+     */
+    public function flush_rewrite_rules_on_activation() {
+        $this->add_oauth_rewrite_rule();
+        flush_rewrite_rules();
+    }
+    
     /**
      * Add OAuth query vars
      */
@@ -429,13 +489,26 @@ class HVAC_Zoho_Admin {
      */
     public function add_oauth_rewrite_rule() {
         add_rewrite_rule('^oauth/callback/?$', 'index.php?hvac_oauth_callback=1', 'top');
+        
+        // Check if we need to flush rewrite rules
+        $rewrite_rules = get_option('rewrite_rules');
+        if (!isset($rewrite_rules['^oauth/callback/?$'])) {
+            // Rules need to be flushed
+            add_action('wp_loaded', 'flush_rewrite_rules');
+        }
     }
     
     /**
      * Handle OAuth template redirect
      */
     public function handle_oauth_template_redirect() {
+        // Debug: Log when this method is called
+        error_log('handle_oauth_template_redirect called');
+        error_log('Query var hvac_oauth_callback: ' . get_query_var('hvac_oauth_callback'));
+        error_log('Request URI: ' . $_SERVER['REQUEST_URI']);
+        
         if (get_query_var('hvac_oauth_callback')) {
+            error_log('Processing OAuth callback');
             $this->process_oauth_callback();
         }
     }
@@ -444,7 +517,11 @@ class HVAC_Zoho_Admin {
      * Process OAuth callback from Zoho
      */
     public function process_oauth_callback() {
+        error_log('process_oauth_callback called');
+        error_log('GET parameters: ' . print_r($_GET, true));
+        
         if (!isset($_GET['code'])) {
+            error_log('OAuth callback missing authorization code');
             wp_die('OAuth callback missing authorization code');
         }
         
@@ -497,6 +574,8 @@ class HVAC_Zoho_Admin {
         
         error_log('OAuth tokens saved successfully');
         
+        error_log('OAuth tokens saved successfully, redirecting to admin page');
+        
         // Success - redirect to admin page with success message
         wp_redirect(admin_url('admin.php?page=hvac-zoho-sync&oauth_success=1'));
         exit;