Validate BMLT root server on save (reject invalid/unreachable hostnames) [#282]

assets/js/src/components/admin/Settings.js

@@ -78,6 +78,7 @@ const Settings = () => {
     });
     const [isLoading, setIsLoading] = useState(true);
     const [isSaving, setIsSaving] = useState(false);
+    const [isTesting, setIsTesting] = useState(false);
     const [error, setError] = useState(null);
     const [successMessage, setSuccessMessage] = useState(null);
     const [externalSources, setExternalSources] = useState([]);
@@ -338,6 +339,30 @@ const Settings = () => {
         }
     };
 
+    const handleTestConnection = async () => {
+        try {
+            setIsTesting(true);
+            setError(null);
+            setSuccessMessage(null);
+
+            if (!isValidHttpsUrl(settings.bmlt_root_server)) {
+                throw new Error(__('BMLT Root Server URL must use HTTPS protocol.', 'mayo-events-manager'));
+            }
+
+            await apiFetch('/validate-root-server', {
+                method: 'POST',
+                body: JSON.stringify({ bmlt_root_server: settings.bmlt_root_server })
+            });
+
+            setSuccessMessage(__('Successfully connected to the BMLT root server.', 'mayo-events-manager'));
+            setTimeout(() => setSuccessMessage(null), 3000);
+        } catch (err) {
+            setError(err.message || __('Could not reach the BMLT root server.', 'mayo-events-manager'));
+        } finally {
+            setIsTesting(false);
+        }
+    };
+
     if (isLoading) {
         return (
             <div className="mayo-settings-loading">
@@ -381,22 +406,34 @@ const Settings = () => {
             <Panel>
                 <PanelBody title={__('BMLT Settings', 'mayo-events-manager')} initialOpen={true}>
                     <PanelRow>
-                        <TextControl
-                            label={__('BMLT Root Server URL', 'mayo-events-manager')}
-                            value={settings.bmlt_root_server}
-                            onChange={(value) => handleChange('bmlt_root_server', value)}
-                            help={
-                                settings.bmlt_root_server && !isValidHttpsUrl(settings.bmlt_root_server)
-                                    ? __("URL must start with 'https://'", 'mayo-events-manager')
-                                    : __('Enter the URL of your BMLT root server (e.g., https://bmlt.example.org/main_server)', 'mayo-events-manager')
-                            }
-                            className={
-                                settings.bmlt_root_server && !isValidHttpsUrl(settings.bmlt_root_server)
-                                    ? 'mayo-invalid-url'
-                                    : ''
-                            }
-                            __next40pxDefaultSize={true}
-                        />
+                        <div style={{ display: 'flex', alignItems: 'center', gap: '8px', width: '100%' }}>
+                            <div style={{ flex: 1 }}>
+                                <TextControl
+                                    label={__('BMLT Root Server URL', 'mayo-events-manager')}
+                                    value={settings.bmlt_root_server}
+                                    onChange={(value) => handleChange('bmlt_root_server', value)}
+                                    help={
+                                        settings.bmlt_root_server && !isValidHttpsUrl(settings.bmlt_root_server)
+                                            ? __("URL must start with 'https://'", 'mayo-events-manager')
+                                            : __('Enter the URL of your BMLT root server (e.g., https://bmlt.example.org/main_server)', 'mayo-events-manager')
+                                    }
+                                    className={
+                                        settings.bmlt_root_server && !isValidHttpsUrl(settings.bmlt_root_server)
+                                            ? 'mayo-invalid-url'
+                                            : ''
+                                    }
+                                    __next40pxDefaultSize={true}
+                                />
+                            </div>
+                            <Button
+                                isSecondary
+                                onClick={handleTestConnection}
+                                isBusy={isTesting}
+                                disabled={isTesting || !isValidHttpsUrl(settings.bmlt_root_server)}
+                            >
+                                {isTesting ? __('Testing…', 'mayo-events-manager') : __('Test connection', 'mayo-events-manager')}
+                            </Button>
+                        </div>
                     </PanelRow>
 
                     <PanelRow>

assets/js/src/util.js

@@ -217,7 +217,18 @@ export const apiFetch = async (endpoint, options = {}) => {
         const response = await fetch(url, fetchOptions);
 
         if (!response.ok) {
-            throw new Error(`API error: ${response.status} ${response.statusText}`);
+            // Prefer the REST API error message (e.g. WP_Error) when present
+            // so callers can show a meaningful reason instead of a bare status.
+            let message = `API error: ${response.status} ${response.statusText}`;
+            try {
+                const errorBody = await response.json();
+                if (errorBody && errorBody.message) {
+                    message = errorBody.message;
+                }
+            } catch (e) {
+                // Response body wasn't JSON; keep the status-based message.
+            }
+            throw new Error(message);
         }
 
         return await response.json();

includes/Rest/Helpers/RootServerValidator.php

@@ -0,0 +1,141 @@
+<?php
+
+namespace BmltEnabled\Mayo\Rest\Helpers;
+
+if ( ! defined( 'ABSPATH' ) ) exit;
+
+/**
+ * Validates that a BMLT root server URL is well-formed and reachable.
+ *
+ * Performs cheap checks first (format, scheme) before an outbound handshake
+ * against the BMLT semantic endpoint to confirm the URL actually points at a
+ * BMLT root server.
+ */
+class RootServerValidator {
+
+    /**
+     * Timeout, in seconds, for the outbound reachability handshake.
+     *
+     * Kept shorter than the read-path lookup in ServiceBodyLookup (15s) so a
+     * slow host can't hang a settings save for long.
+     */
+    const TIMEOUT = 10;
+
+    /**
+     * Validate and normalize a BMLT root server URL.
+     *
+     * @param string $url The candidate root server URL.
+     * @return string|\WP_Error Normalized URL (no trailing slash) on success,
+     *                          or a WP_Error describing why validation failed.
+     */
+    public static function validate( $url ) {
+        $url = is_string( $url ) ? trim( $url ) : '';
+
+        if ( $url === '' ) {
+            return new \WP_Error(
+                'invalid_root_server_url',
+                __( 'Please enter a BMLT root server URL.', 'mayo-events-manager' ),
+                [ 'status' => 400 ]
+            );
+        }
+
+        // 1. Format — must be a valid absolute URL.
+        $normalized = untrailingslashit( esc_url_raw( $url ) );
+
+        if ( empty( $normalized ) || ! wp_http_validate_url( $normalized ) ) {
+            return new \WP_Error(
+                'invalid_root_server_url',
+                sprintf(
+                    /* translators: %s: the URL the user entered. */
+                    __( '"%s" is not a valid URL.', 'mayo-events-manager' ),
+                    $url
+                ),
+                [ 'status' => 400 ]
+            );
+        }
+
+        // 2. Scheme — require https.
+        $scheme = strtolower( (string) wp_parse_url( $normalized, PHP_URL_SCHEME ) );
+        if ( $scheme !== 'https' ) {
+            return new \WP_Error(
+                'invalid_root_server_url',
+                sprintf(
+                    /* translators: %s: the URL the user entered. */
+                    __( 'The BMLT root server URL must start with "https://" (got "%s").', 'mayo-events-manager' ),
+                    $url
+                ),
+                [ 'status' => 400 ]
+            );
+        }
+
+        // 3. Reachability — handshake against the BMLT semantic endpoint.
+        $response = wp_remote_get(
+            $normalized . '/client_interface/json/?switcher=GetServerInfo',
+            [
+                'timeout'   => self::TIMEOUT,
+                'sslverify' => true,
+            ]
+        );
+
+        if ( is_wp_error( $response ) ) {
+            return new \WP_Error(
+                'root_server_unreachable',
+                sprintf(
+                    /* translators: %s: the BMLT root server URL. */
+                    __( 'Could not reach a BMLT root server at %s', 'mayo-events-manager' ),
+                    $normalized
+                ),
+                [ 'status' => 400 ]
+            );
+        }
+
+        $code = (int) wp_remote_retrieve_response_code( $response );
+        if ( $code !== 200 ) {
+            return new \WP_Error(
+                'root_server_unreachable',
+                sprintf(
+                    /* translators: 1: the BMLT root server URL, 2: the HTTP status code returned. */
+                    __( 'Could not reach a BMLT root server at %1$s (HTTP %2$d).', 'mayo-events-manager' ),
+                    $normalized,
+                    $code
+                ),
+                [ 'status' => 400 ]
+            );
+        }
+
+        $data = json_decode( wp_remote_retrieve_body( $response ), true );
+        if ( ! self::looks_like_server_info( $data ) ) {
+            return new \WP_Error(
+                'not_a_bmlt_root_server',
+                sprintf(
+                    /* translators: %s: the BMLT root server URL. */
+                    __( 'The URL %s did not respond like a BMLT root server.', 'mayo-events-manager' ),
+                    $normalized
+                ),
+                [ 'status' => 400 ]
+            );
+        }
+
+        return $normalized;
+    }
+
+    /**
+     * Determine whether a decoded GetServerInfo response looks like a BMLT
+     * root server. GetServerInfo returns a single-element list of objects
+     * carrying a `version` field, e.g. [ { "version": "3.0.0", ... } ].
+     *
+     * @param mixed $data Decoded JSON response body.
+     * @return bool
+     */
+    private static function looks_like_server_info( $data ) {
+        if ( ! is_array( $data ) ) {
+            return false;
+        }
+
+        if ( isset( $data['version'] ) ) {
+            return true;
+        }
+
+        return isset( $data[0] ) && is_array( $data[0] ) && isset( $data[0]['version'] );
+    }
+}

includes/Rest/SettingsController.php

@@ -2,6 +2,8 @@
 
 namespace BmltEnabled\Mayo\Rest;
 
+use BmltEnabled\Mayo\Rest\Helpers\RootServerValidator;
+
 if ( ! defined( 'ABSPATH' ) ) exit;
 
 /**
@@ -26,6 +28,14 @@ public static function register_routes() {
                 return current_user_can('manage_options');
             }
         ]);
+
+        register_rest_route('event-manager/v1', '/validate-root-server', [
+            'methods' => 'POST',
+            'callback' => [__CLASS__, 'validate_root_server'],
+            'permission_callback' => function() {
+                return current_user_can('manage_options');
+            }
+        ]);
     }
 
     /**
@@ -78,9 +88,25 @@ public static function update_settings($request) {
         $params = $request->get_params();
         $settings = get_option('mayo_settings', []);
 
-        // Update BMLT root server
+        // Update BMLT root server. Validate only when the value actually
+        // changes so saving unrelated settings (or re-saving an already-valid
+        // root that is momentarily unreachable) never triggers a network call
+        // or blocks the save. The bad value is never persisted: an invalid
+        // root server returns early before any update_option(), preserving the
+        // previously stored value.
         if (isset($params['bmlt_root_server'])) {
-            $settings['bmlt_root_server'] = sanitize_text_field($params['bmlt_root_server']);
+            $new_root = sanitize_text_field($params['bmlt_root_server']);
+            $current_root = $settings['bmlt_root_server'] ?? '';
+
+            if ($new_root === '') {
+                $settings['bmlt_root_server'] = '';
+            } elseif ($new_root !== $current_root) {
+                $validated = RootServerValidator::validate($new_root);
+                if (is_wp_error($validated)) {
+                    return $validated;
+                }
+                $settings['bmlt_root_server'] = $validated;
+            }
         }
 
         // Update notification email
@@ -156,6 +182,36 @@ public static function update_settings($request) {
         ]);
     }
 
+    /**
+     * Validate a BMLT root server URL without saving it.
+     *
+     * Backs the "Test connection" affordance in the admin Settings UI.
+     *
+     * @param \WP_REST_Request $request
+     * @return \WP_REST_Response|\WP_Error
+     */
+    public static function validate_root_server($request) {
+        if (!current_user_can('manage_options')) {
+            return new \WP_Error(
+                'rest_forbidden',
+                __('Sorry, you are not allowed to validate settings.', 'mayo-events-manager'),
+                ['status' => 401]
+            );
+        }
+
+        $url = sanitize_text_field($request->get_param('bmlt_root_server') ?? '');
+        $result = RootServerValidator::validate($url);
+
+        if (is_wp_error($result)) {
+            return $result;
+        }
+
+        return new \WP_REST_Response([
+            'success' => true,
+            'bmlt_root_server' => $result,
+        ]);
+    }
+
     /**
      * Generate a readable ID for external sources
      *