felixarntz · Aug 9, 2023 · Jul 18, 2023 · Jul 21, 2023 · Jul 21, 2023 · Jul 21, 2023
diff --git a/admin/load.php b/admin/load.php
@@ -111,7 +111,7 @@ function perflab_render_modules_page() {
 			<?php esc_html_e( 'Performance Modules', 'performance-lab' ); ?>
 		</h1>
 
-		<form action="options.php" method="post" novalidate="novalidate">
+		<form action="options.php" method="post">
 			<?php settings_fields( PERFLAB_MODULES_SCREEN ); ?>
 			<?php do_settings_sections( PERFLAB_MODULES_SCREEN ); ?>
 			<?php submit_button(); ?>

diff --git a/admin/server-timing.php b/admin/server-timing.php
@@ -0,0 +1,165 @@
+<?php
+/**
+ * Server-Timing API admin integration file.
+ *
+ * @package performance-lab
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit; // Exit if accessed directly.
+}
+
+/**
+ * Adds the Server-Timing page to the Tools menu.
+ *
+ * @since n.e.x.t
+ */
+function perflab_add_server_timing_page() {
+	$hook_suffix = add_management_page(
+		__( 'Server-Timing', 'performance-lab' ),
+		__( 'Server-Timing', 'performance-lab' ),
+		'manage_options',
+		PERFLAB_SERVER_TIMING_SCREEN,
+		'perflab_render_server_timing_page'
+	);
+
+	// Add the following hooks only if the screen was successfully added.
+	if ( false !== $hook_suffix ) {
+		add_action( "load-{$hook_suffix}", 'perflab_load_server_timing_page' );
+	}
+
+	return $hook_suffix;
+}
+add_action( 'admin_menu', 'perflab_add_server_timing_page' );
+
+/**
+ * Initializes settings sections and fields for the Server-Timing page.
+ *
+ * @since n.e.x.t
+ */
+function perflab_load_server_timing_page() {
+	add_settings_section(
+		'benchmarking',
+		__( 'Benchmarking', 'performance-lab' ),
+		static function() {
+			?>
+			<p>
+				<?php
+				echo wp_kses(
+					sprintf(
+						/* translators: %s: Server-Timing */
+						__( 'In this section, you can provide hook names to include measurements for them in the %s header.', 'performance-lab' ),
+						'<code>Server-Timing</code>'
+					),
+					array( 'code' => array() )
+				);
+				?>
+				<br>
+				<?php
+				echo wp_kses(
+					__( 'For any hook name provided, the <strong>cumulative duration between all callbacks</strong> attached to the hook is measured, in milliseconds.', 'performance-lab' ),
+					array( 'strong' => array() )
+				);
+				if ( ! perflab_server_timing_use_output_buffer() ) {
+					?>
+					<br>
+					<?php
+					echo wp_kses(
+						sprintf(
+							/* translators: 1: Server-Timing, 2: template_include */
+							__( 'Since the %1$s header is sent before the template is loaded, only hooks before the %2$s filter can be measured.', 'performance-lab' ),
+							'<code>Server-Timing</code>',
+							'<code>template_include</code>'
+						),
+						array( 'code' => array() )
+					);
+				}
+				?>
+			</p>
+			<?php
+		},
+		PERFLAB_SERVER_TIMING_SCREEN
+	);
+
+	/*
+	 * For all settings fields, the field slug, option sub key, and label
+	 * suffix have to match for the rendering in the callback to be
+	 * semantically correct.
+	 */
+	add_settings_field(
+		'benchmarking_actions',
+		__( 'Actions', 'performance-lab' ),
+		static function() {
+			perflab_render_server_timing_page_field( 'benchmarking_actions' );
+		},
+		PERFLAB_SERVER_TIMING_SCREEN,
+		'benchmarking',
+		array( 'label_for' => 'server_timing_benchmarking_actions' )
+	);
+	add_settings_field(
+		'benchmarking_filters',
+		__( 'Filters', 'performance-lab' ),
+		static function() {
+			perflab_render_server_timing_page_field( 'benchmarking_filters' );
+		},
+		PERFLAB_SERVER_TIMING_SCREEN,
+		'benchmarking',
+		array( 'label_for' => 'server_timing_benchmarking_filters' )
+	);
+}
+
+/**
+ * Renders the Server-Timing page.
+ *
+ * @since n.e.x.t
+ */
+function perflab_render_server_timing_page() {
+	?>
+	<div class="wrap">
+		<?php settings_errors(); ?>
+		<h1>
+			<?php esc_html_e( 'Server-Timing', 'performance-lab' ); ?>
+		</h1>
+
+		<form action="options.php" method="post">
+			<?php settings_fields( PERFLAB_SERVER_TIMING_SCREEN ); ?>
+			<?php do_settings_sections( PERFLAB_SERVER_TIMING_SCREEN ); ?>
+			<?php submit_button(); ?>
+		</form>
+	</div>
+	<?php
+}
+
+/**
+ * Renders a field for the given Server-Timing option.
+ *
+ * @since n.e.x.t
+ *
+ * @param string $slug Slug of the field and sub-key in the Server-Timing option.
+ */
+function perflab_render_server_timing_page_field( $slug ) {
+	$options = (array) get_option( PERFLAB_SERVER_TIMING_SETTING, array() );
+
+	// Value for the sub-key is an array of hook names.
+	$value = '';
+	if ( isset( $options[ $slug ] ) ) {
+		$value = implode( "\n", $options[ $slug ] );
+	}
+
+	$field_id       = "server_timing_{$slug}";
+	$field_name     = PERFLAB_SERVER_TIMING_SETTING . '[' . $slug . ']';
+	$description_id = "{$field_id}_description";
+
+	?>
+	<textarea
+		id="<?php echo esc_attr( $field_id ); ?>"
+		name="<?php echo esc_attr( $field_name ); ?>"
+		aria-describedby="<?php echo esc_attr( $description_id ); ?>"
+		class="large-text code"
+		rows="8"
+	><?php echo esc_textarea( $value ); ?></textarea>
+	<p id="<?php echo esc_attr( $description_id ); ?>" class="description">
+		<?php esc_html_e( 'Enter a single hook name per line.', 'performance-lab' ); ?>
+	</p>
+	<?php
+}
diff --git a/load.php b/load.php
@@ -435,6 +435,7 @@ function perflab_maybe_remove_object_cache_dropin() {
 // Only load admin integration when in admin.
 if ( is_admin() ) {
 	require_once PERFLAB_PLUGIN_DIR_PATH . 'admin/load.php';
+	require_once PERFLAB_PLUGIN_DIR_PATH . 'admin/server-timing.php';
 }
 
 /**

diff --git a/server-timing/defaults.php b/server-timing/defaults.php
@@ -211,3 +211,106 @@ static function( $acc, $query ) {
 	}
 }
 add_action( 'wp_loaded', 'perflab_register_default_server_timing_template_metrics' );
+
+/**
+ * Registers additional Server-Timing metrics as configured in the setting.
+ *
+ * These metrics should be registered as soon as possible. They can be added
+ * and modified in the "Tools > Server-Timing" screen.
+ *
+ * @since n.e.x.t
+ */
+function perflab_register_additional_server_timing_metrics_from_setting() {
+	$options = (array) get_option( PERFLAB_SERVER_TIMING_SETTING, array() );
+
+	$hooks_to_measure = array();
+
+	if ( isset( $options['benchmarking_actions'] ) ) {
+		foreach ( $options['benchmarking_actions'] as $action ) {
+			$hooks_to_measure[ $action ] = 'action';
+		}
+	}
+
+	if ( isset( $options['benchmarking_filters'] ) ) {
+		foreach ( $options['benchmarking_filters'] as $filter ) {
+			$hooks_to_measure[ $filter ] = 'filter';
+		}
+	}
+
+	// Bail early if there are no hooks to measure.
+	if ( ! $hooks_to_measure ) {
+		return;
+	}
+
+	/*
+	 * This logic measures performance of a hook (action or filter).
+	 *
+	 * Currently, only hooks that run once are properly supported.
+	 * For hooks that run multiple times, only the first occurrence will be measured.
+	 *
+	 * Here is an outline of the logic:
+	 *
+	 * 1. Use the 'all' hook at the minimum (i.e. earliest) priority possible.
+	 * 2. In that callback, check that the hook should be measured and that it has not already been registered yet, and
+	 *    if so, register the metric for the hook, with a prefix of either "action" or "filter".
+	 * 3. Provide a measuring callback which captures the time span between beginning to end of the hook:
+	 *     1. Capture the current time immediately, i.e. within the 'all' hook.
+	 *     2. Add another hook callback at the maximum (i.e. latest) priority possible.
+	 *     3. In that callback, capture the current time, leading the Server-Timing API to calculate the difference.
+	 */
+	add_action(
+		'all',
+		static function( $hook_name ) use ( $hooks_to_measure ) {
+			if ( ! isset( $hooks_to_measure[ $hook_name ] ) ) {
+				return;
+			}
+
+			$hook_type   = $hooks_to_measure[ $hook_name ];
+			$metric_slug = "{$hook_type}-{$hook_name}";
+
+			if ( perflab_server_timing()->has_registered_metric( $metric_slug ) ) {
+				return;
+			}
+
+			$measure_callback = static function( $metric ) use ( $hook_name, $hook_type ) {
+				$metric->measure_before();
+
+				if ( 'action' === $hook_type ) {
+					$cb = static function() use ( $metric, $hook_name, &$cb ) {
+						$metric->measure_after();
+						remove_action( $hook_name, $cb, PHP_INT_MAX );
+					};
+					add_action( $hook_name, $cb, PHP_INT_MAX );
+				} else {
+					$cb = static function( $passthrough ) use ( $metric, $hook_name, &$cb ) {
+						$metric->measure_after();
+						remove_filter( $hook_name, $cb, PHP_INT_MAX );
+						return $passthrough;
+					};
+					add_filter( $hook_name, $cb, PHP_INT_MAX );
+				}
+			};
+
+			perflab_server_timing_register_metric(
+				$metric_slug,
+				array(
+					'measure_callback' => $measure_callback,
+					'access_cap'       => 'exist',
+				)
+			);
+		},
+		// phpcs:ignore PHPCompatibility.Constants.NewConstants.php_int_minFound
+		defined( 'PHP_INT_MIN' ) ? PHP_INT_MIN : ~PHP_INT_MAX
+	);
+}
+
+/*
+ * If this file is loaded from the Server-Timing logic in the object-cache.php
+ * drop-in, it must not call this function right away since otherwise the cache
+ * will not be loaded yet.
+ */
+if ( ! did_action( 'muplugins_loaded' ) ) {
+	add_action( 'muplugins_loaded', 'perflab_register_additional_server_timing_metrics_from_setting' );
+} else {
+	perflab_register_additional_server_timing_metrics_from_setting();
+}
diff --git a/server-timing/load.php b/server-timing/load.php
@@ -10,6 +10,9 @@
 	exit; // Exit if accessed directly.
 }
 
+define( 'PERFLAB_SERVER_TIMING_SETTING', 'perflab_server_timing_settings' );
+define( 'PERFLAB_SERVER_TIMING_SCREEN', 'perflab-server-timing' );
+
 /**
  * Provides access the Server-Timing API.
  *
@@ -113,3 +116,76 @@ function perflab_wrap_server_timing( $callback, $metric_slug, $access_cap ) {
 		return $result;
 	};
 }
+
+/**
+ * Registers the Server-Timing setting.
+ *
+ * @since n.e.x.t
+ */
+function perflab_register_server_timing_setting() {
+	register_setting(
+		PERFLAB_SERVER_TIMING_SCREEN,
+		PERFLAB_SERVER_TIMING_SETTING,
+		array(
+			'type'              => 'object',
+			'sanitize_callback' => 'perflab_sanitize_server_timing_setting',
+			'default'           => array(),
+		)
+	);
+}
+add_action( 'init', 'perflab_register_server_timing_setting' );
+
+/**
+ * Sanitizes the Server-Timing setting.
+ *
+ * @since n.e.x.t
+ *
+ * @param mixed $value Server-Timing setting value.
+ * @return array Sanitized Server-Timing setting value.
+ */
+function perflab_sanitize_server_timing_setting( $value ) {
+	static $allowed_keys = array(
+		'benchmarking_actions' => true,
+		'benchmarking_filters' => true,
+	);
+
+	if ( ! is_array( $value ) ) {
+		return array();
+	}
+
+	$value = array_intersect_key( $value, $allowed_keys );
+
+	/*
+	 * Ensure that every element is an indexed array of hook names.
+	 * Any duplicates across a group of hooks are removed.
+	 */
+	foreach ( $value as $key => $hooks ) {
+		if ( ! is_array( $hooks ) ) {
+			$hooks = explode( "\n", $hooks );
+		}
+		$value[ $key ] = array_values(
+			array_unique(
+				array_filter(
+					array_map(
+						static function( $hookname ) {
+							/*
+							 * Allow any characters except whitespace.
+							 * While most hooks use a limited set of characters, hook names in plugins are not
+							 * restricted to them, therefore the sanitization does not limit the characters
+							 * used.
+							 */
+							return preg_replace(
+								'/\s/',
+								'',
+								sanitize_text_field( $hookname )
+							);
+						},
+						$hooks
+					)
+				)
+			)
+		);
+	}
+
+	return $value;
+}
diff --git a/tests/admin/load-tests.php b/tests/admin/load-tests.php
@@ -5,6 +5,9 @@
  * @package performance-lab
  */
 
+/**
+ * @group admin
+ */
 class Admin_Load_Tests extends WP_UnitTestCase {
 
 	private static $demo_modules = array(