feat: Add dashboard extension hook for third-party plugins (v0.4.6)

Add wp_prometheus_register_dashboards action hook allowing third-party
plugins to register their own Grafana dashboard templates.

- DashboardProvider: registration system with file/JSON support
- Security: path traversal protection, JSON validation
- Admin UI: "Extension" badge and plugin attribution
- Isolated mode support for dashboard registration hook

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Admin/DashboardProvider.php

@@ -16,22 +16,37 @@ if ( ! defined( 'ABSPATH' ) ) {
  * DashboardProvider class.
  *
  * Provides Grafana dashboard templates for download.
+ * Supports both built-in dashboards and third-party registrations.
  */
 class DashboardProvider {
 
 	/**
-	 * Dashboard directory path.
+	 * Dashboard directory path for built-in dashboards.
 	 *
 	 * @var string
 	 */
 	private string $dashboard_dir;
 
 	/**
-	 * Available dashboard definitions.
+	 * Built-in dashboard definitions.
 	 *
 	 * @var array
 	 */
-	private array $dashboards = array();
+	private array $builtin_dashboards = array();
+
+	/**
+	 * Third-party registered dashboard definitions.
+	 *
+	 * @var array
+	 */
+	private array $registered_dashboards = array();
+
+	/**
+	 * Whether the registration hook has been fired.
+	 *
+	 * @var bool
+	 */
+	private bool $hook_fired = false;
 
 	/**
 	 * Constructor.
@@ -39,43 +54,241 @@ class DashboardProvider {
 	public function __construct() {
 		$this->dashboard_dir = WP_PROMETHEUS_PATH . 'assets/dashboards/';
 
-		$this->dashboards = array(
+		$this->builtin_dashboards = array(
 			'wordpress-overview'    => array(
 				'title'       => __( 'WordPress Overview', 'wp-prometheus' ),
 				'description' => __( 'General WordPress metrics including users, posts, comments, and plugins.', 'wp-prometheus' ),
 				'file'        => 'wordpress-overview.json',
 				'icon'        => 'dashicons-wordpress',
+				'source'      => 'builtin',
 			),
 			'wordpress-runtime'     => array(
 				'title'       => __( 'Runtime Performance', 'wp-prometheus' ),
 				'description' => __( 'HTTP request metrics, database query performance, and response times.', 'wp-prometheus' ),
 				'file'        => 'wordpress-runtime.json',
 				'icon'        => 'dashicons-performance',
+				'source'      => 'builtin',
 			),
 			'wordpress-woocommerce' => array(
 				'title'       => __( 'WooCommerce Store', 'wp-prometheus' ),
 				'description' => __( 'WooCommerce metrics including products, orders, revenue, and customers.', 'wp-prometheus' ),
 				'file'        => 'wordpress-woocommerce.json',
 				'icon'        => 'dashicons-cart',
+				'source'      => 'builtin',
 			),
 		);
 	}
 
+	/**
+	 * Register a third-party dashboard.
+	 *
+	 * @param string $slug Dashboard slug (unique identifier).
+	 * @param array  $args Dashboard configuration {
+	 *     @type string $title       Dashboard title (required).
+	 *     @type string $description Dashboard description.
+	 *     @type string $icon        Dashicon class (e.g., 'dashicons-chart-bar').
+	 *     @type string $file        Absolute path to JSON file (mutually exclusive with 'json').
+	 *     @type string $json        Inline JSON content (mutually exclusive with 'file').
+	 *     @type string $plugin      Plugin name for attribution.
+	 * }
+	 * @return bool True if registered successfully, false otherwise.
+	 */
+	public function register_dashboard( string $slug, array $args ): bool {
+		// Sanitize slug - must be valid identifier.
+		$slug = sanitize_key( $slug );
+
+		if ( empty( $slug ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( 'WP Prometheus: Dashboard registration failed - invalid slug' );
+			}
+			return false;
+		}
+
+		// Check for duplicate slugs (built-in takes precedence).
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard slug '$slug' conflicts with built-in dashboard" );
+			}
+			return false;
+		}
+
+		// Check for duplicate slugs in already registered dashboards.
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard slug '$slug' already registered" );
+			}
+			return false;
+		}
+
+		// Validate required fields.
+		if ( empty( $args['title'] ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard '$slug' missing required 'title'" );
+			}
+			return false;
+		}
+
+		// Must have either 'file' or 'json', not both.
+		$has_file = ! empty( $args['file'] );
+		$has_json = ! empty( $args['json'] );
+
+		if ( ! $has_file && ! $has_json ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard '$slug' must have 'file' or 'json'" );
+			}
+			return false;
+		}
+
+		if ( $has_file && $has_json ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard '$slug' cannot have both 'file' and 'json'" );
+			}
+			return false;
+		}
+
+		// Validate file path if provided.
+		if ( $has_file ) {
+			$file_path = $args['file'];
+
+			// Must be absolute path.
+			if ( ! path_is_absolute( $file_path ) ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' file path must be absolute" );
+				}
+				return false;
+			}
+
+			// File must exist and be readable.
+			if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' file not found: $file_path" );
+				}
+				return false;
+			}
+
+			// Security: Prevent path traversal - file must be under wp-content.
+			$real_path      = realpath( $file_path );
+			$wp_content_dir = realpath( WP_CONTENT_DIR );
+
+			if ( false === $real_path || false === $wp_content_dir ||
+				strpos( $real_path, $wp_content_dir ) !== 0 ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' file outside wp-content" );
+				}
+				return false;
+			}
+		}
+
+		// Validate JSON if provided inline.
+		if ( $has_json ) {
+			$decoded = json_decode( $args['json'], true );
+			if ( null === $decoded && json_last_error() !== JSON_ERROR_NONE ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' has invalid JSON" );
+				}
+				return false;
+			}
+		}
+
+		// Build dashboard entry.
+		$this->registered_dashboards[ $slug ] = array(
+			'title'       => sanitize_text_field( $args['title'] ),
+			'description' => sanitize_text_field( $args['description'] ?? '' ),
+			'icon'        => sanitize_html_class( $args['icon'] ?? 'dashicons-chart-line' ),
+			'file'        => $has_file ? $file_path : null,
+			'json'        => $has_json ? $args['json'] : null,
+			'plugin'      => sanitize_text_field( $args['plugin'] ?? '' ),
+			'source'      => 'third-party',
+		);
+
+		return true;
+	}
+
+	/**
+	 * Fire the dashboard registration hook with protection.
+	 *
+	 * @return void
+	 */
+	private function fire_registration_hook(): void {
+		if ( $this->hook_fired ) {
+			return;
+		}
+
+		$this->hook_fired = true;
+
+		// Check for isolated mode - skip third-party hooks.
+		$isolated_mode = defined( 'WP_PROMETHEUS_ISOLATED_MODE' ) && WP_PROMETHEUS_ISOLATED_MODE;
+
+		// Also check option for admin-side isolated mode.
+		if ( ! $isolated_mode ) {
+			$isolated_mode = (bool) get_option( 'wp_prometheus_isolated_mode', false );
+		}
+
+		if ( $isolated_mode ) {
+			return;
+		}
+
+		// Use output buffering to capture any accidental output.
+		ob_start();
+
+		try {
+			/**
+			 * Fires to allow third-party plugins to register dashboards.
+			 *
+			 * @since 0.4.6
+			 *
+			 * @param DashboardProvider $provider The dashboard provider instance.
+			 */
+			do_action( 'wp_prometheus_register_dashboards', $this );
+		} catch ( \Throwable $e ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( 'WP Prometheus: Error in dashboard registration hook: ' . $e->getMessage() );
+			}
+		}
+
+		// Discard any output from plugins.
+		ob_end_clean();
+	}
+
 	/**
 	 * Get list of available dashboards.
 	 *
 	 * @return array
 	 */
 	public function get_available(): array {
+		// Fire registration hook first (only once).
+		$this->fire_registration_hook();
+
 		$available = array();
 
-		foreach ( $this->dashboards as $slug => $dashboard ) {
+		// Add built-in dashboards (check file exists).
+		foreach ( $this->builtin_dashboards as $slug => $dashboard ) {
 			$file_path = $this->dashboard_dir . $dashboard['file'];
 			if ( file_exists( $file_path ) ) {
 				$available[ $slug ] = $dashboard;
 			}
 		}
 
+		// Add registered third-party dashboards.
+		foreach ( $this->registered_dashboards as $slug => $dashboard ) {
+			// Already validated during registration, but double-check.
+			if ( ! empty( $dashboard['json'] ) ||
+				( ! empty( $dashboard['file'] ) && file_exists( $dashboard['file'] ) ) ) {
+				$available[ $slug ] = $dashboard;
+			}
+		}
+
 		return $available;
 	}
 
@@ -86,35 +299,70 @@ class DashboardProvider {
 	 * @return string|null JSON content or null if not found.
 	 */
 	public function get_dashboard( string $slug ): ?string {
-		// Validate slug to prevent directory traversal.
+		// Fire registration hook first.
+		$this->fire_registration_hook();
+
+		// Validate slug.
 		$slug = sanitize_file_name( $slug );
 
-		if ( ! isset( $this->dashboards[ $slug ] ) ) {
-			return null;
+		// Check built-in dashboards first.
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
+			$dashboard = $this->builtin_dashboards[ $slug ];
+			$file_path = $this->dashboard_dir . $dashboard['file'];
+
+			// Security: Ensure file is within dashboard directory.
+			$real_path = realpath( $file_path );
+			$real_dir  = realpath( $this->dashboard_dir );
+
+			if ( false === $real_path || false === $real_dir ||
+				strpos( $real_path, $real_dir ) !== 0 ) {
+				return null;
+			}
+
+			if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
+				return null;
+			}
+
+			// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
+			$content = file_get_contents( $file_path );
+
+			return false === $content ? null : $content;
 		}
 
-		$file_path = $this->dashboard_dir . $this->dashboards[ $slug ]['file'];
+		// Check registered dashboards.
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			$dashboard = $this->registered_dashboards[ $slug ];
 
-		// Security: Ensure file is within dashboard directory.
-		$real_path = realpath( $file_path );
-		$real_dir  = realpath( $this->dashboard_dir );
+			// Inline JSON.
+			if ( ! empty( $dashboard['json'] ) ) {
+				return $dashboard['json'];
+			}
 
-		if ( false === $real_path || false === $real_dir || strpos( $real_path, $real_dir ) !== 0 ) {
-			return null;
+			// File-based.
+			if ( ! empty( $dashboard['file'] ) ) {
+				$file_path = $dashboard['file'];
+
+				// Security: Re-verify file is under wp-content.
+				$real_path      = realpath( $file_path );
+				$wp_content_dir = realpath( WP_CONTENT_DIR );
+
+				if ( false === $real_path || false === $wp_content_dir ||
+					strpos( $real_path, $wp_content_dir ) !== 0 ) {
+					return null;
+				}
+
+				if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
+					return null;
+				}
+
+				// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
+				$content = file_get_contents( $file_path );
+
+				return false === $content ? null : $content;
+			}
 		}
 
-		if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
-			return null;
-		}
-
-		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
-		$content = file_get_contents( $file_path );
-
-		if ( false === $content ) {
-			return null;
-		}
-
-		return $content;
+		return null;
 	}
 
 	/**
@@ -124,13 +372,20 @@ class DashboardProvider {
 	 * @return array|null Dashboard metadata or null if not found.
 	 */
 	public function get_metadata( string $slug ): ?array {
+		// Fire registration hook first.
+		$this->fire_registration_hook();
+
 		$slug = sanitize_file_name( $slug );
 
-		if ( ! isset( $this->dashboards[ $slug ] ) ) {
-			return null;
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
+			return $this->builtin_dashboards[ $slug ];
 		}
 
-		return $this->dashboards[ $slug ];
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			return $this->registered_dashboards[ $slug ];
+		}
+
+		return null;
 	}
 
 	/**
@@ -140,12 +395,61 @@ class DashboardProvider {
 	 * @return string|null Filename or null if not found.
 	 */
 	public function get_filename( string $slug ): ?string {
+		// Fire registration hook first.
+		$this->fire_registration_hook();
+
 		$slug = sanitize_file_name( $slug );
 
-		if ( ! isset( $this->dashboards[ $slug ] ) ) {
-			return null;
+		// Built-in dashboards have predefined filenames.
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
+			return $this->builtin_dashboards[ $slug ]['file'];
 		}
 
-		return $this->dashboards[ $slug ]['file'];
+		// Registered dashboards - use file basename or generate from slug.
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			$dashboard = $this->registered_dashboards[ $slug ];
+
+			if ( ! empty( $dashboard['file'] ) ) {
+				return basename( $dashboard['file'] );
+			}
+
+			// Generate filename from slug for inline JSON.
+			return $slug . '.json';
+		}
+
+		return null;
+	}
+
+	/**
+	 * Check if a dashboard is from a third-party plugin.
+	 *
+	 * @param string $slug Dashboard slug.
+	 * @return bool True if third-party, false if built-in or not found.
+	 */
+	public function is_third_party( string $slug ): bool {
+		$this->fire_registration_hook();
+
+		$slug = sanitize_file_name( $slug );
+
+		return isset( $this->registered_dashboards[ $slug ] );
+	}
+
+	/**
+	 * Get the plugin name for a third-party dashboard.
+	 *
+	 * @param string $slug Dashboard slug.
+	 * @return string|null Plugin name or null if not found/built-in.
+	 */
+	public function get_plugin_name( string $slug ): ?string {
+		$this->fire_registration_hook();
+
+		$slug = sanitize_file_name( $slug );
+
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			$plugin = $this->registered_dashboards[ $slug ]['plugin'];
+			return ! empty( $plugin ) ? $plugin : null;
+		}
+
+		return null;
 	}
 }

src/Admin/Settings.php

@@ -1214,20 +1214,45 @@ class Settings {
 			<h2><?php esc_html_e( 'Grafana Dashboard Templates', 'wp-prometheus' ); ?></h2>
 			<p class="description"><?php esc_html_e( 'Pre-built dashboards for visualizing your WordPress metrics in Grafana.', 'wp-prometheus' ); ?></p>
 
-			<div class="wp-prometheus-dashboard-grid">
-				<?php foreach ( $dashboards as $slug => $dashboard ) : ?>
-					<div class="wp-prometheus-dashboard-card">
-						<div class="dashboard-icon">
-							<span class="dashicons <?php echo esc_attr( $dashboard['icon'] ); ?>"></span>
+			<?php if ( empty( $dashboards ) ) : ?>
+				<p class="description"><?php esc_html_e( 'No dashboards available.', 'wp-prometheus' ); ?></p>
+			<?php else : ?>
+				<div class="wp-prometheus-dashboard-grid">
+					<?php
+					foreach ( $dashboards as $slug => $dashboard ) :
+						$is_third_party = $this->dashboard_provider->is_third_party( $slug );
+						$plugin_name    = $this->dashboard_provider->get_plugin_name( $slug );
+						$card_class     = 'wp-prometheus-dashboard-card' . ( $is_third_party ? ' third-party' : '' );
+						?>
+						<div class="<?php echo esc_attr( $card_class ); ?>">
+							<?php if ( $is_third_party ) : ?>
+								<span class="dashboard-badge"><?php esc_html_e( 'Extension', 'wp-prometheus' ); ?></span>
+							<?php endif; ?>
+							<div class="dashboard-icon">
+								<span class="dashicons <?php echo esc_attr( $dashboard['icon'] ); ?>"></span>
+							</div>
+							<h3><?php echo esc_html( $dashboard['title'] ); ?></h3>
+							<p><?php echo esc_html( $dashboard['description'] ); ?></p>
+							<?php if ( $is_third_party && $plugin_name ) : ?>
+								<p class="dashboard-plugin">
+									<small>
+										<?php
+										printf(
+											/* translators: %s: Plugin name */
+											esc_html__( 'Provided by: %s', 'wp-prometheus' ),
+											esc_html( $plugin_name )
+										);
+										?>
+									</small>
+								</p>
+							<?php endif; ?>
+							<button type="button" class="button button-primary download-dashboard" data-slug="<?php echo esc_attr( $slug ); ?>">
+								<?php esc_html_e( 'Download', 'wp-prometheus' ); ?>
+							</button>
 						</div>
-						<h3><?php echo esc_html( $dashboard['title'] ); ?></h3>
-						<p><?php echo esc_html( $dashboard['description'] ); ?></p>
-						<button type="button" class="button button-primary download-dashboard" data-slug="<?php echo esc_attr( $slug ); ?>">
-							<?php esc_html_e( 'Download', 'wp-prometheus' ); ?>
-						</button>
-					</div>
-				<?php endforeach; ?>
-			</div>
+					<?php endforeach; ?>
+				</div>
+			<?php endif; ?>
 
 			<hr style="margin: 30px 0;">