Abilities API: Add a core/settings ability

src/wp-includes/abilities.php

@@ -9,6 +9,8 @@
 
 declare( strict_types = 1 );
 
+require_once __DIR__ . '/abilities/class-wp-settings-abilities.php';
+
 /**
  * Registers the core ability categories.
  *
@@ -351,4 +353,7 @@ function wp_register_core_abilities(): void {
 			),
 		)
 	);
+
+	// Register the settings abilities (currently the read-only `core/settings`).
+	WP_Settings_Abilities::register();
 }

src/wp-includes/abilities/class-wp-settings-abilities.php

@@ -0,0 +1,290 @@
+<?php
+/**
+ * Abilities API: WP_Settings_Abilities class.
+ *
+ * @package WordPress
+ * @subpackage Abilities API
+ * @since 7.1.0
+ */
+
+declare( strict_types = 1 );
+
+/**
+ * Core class used to register settings-related abilities.
+ *
+ * Provides the read-only `core/settings` ability and the shared building blocks
+ * (exposed-settings discovery, schema generation, value casting) that are intended to
+ * also back a future write-oriented `core/manage-settings` ability.
+ *
+ * This class is part of WordPress' internal implementation of the core abilities and is
+ * not part of the public API. It may be changed or removed at any time without notice.
+ * Do not use it directly or rely on its existence.
+ *
+ * @since 7.1.0
+ *
+ * @access private
+ */
+class WP_Settings_Abilities {
+
+	/**
+	 * The ability category used for settings abilities.
+	 *
+	 * @since 7.1.0
+	 * @var string
+	 */
+	const CATEGORY = 'site';
+
+	/**
+	 * Settings exposed through the Abilities API, computed once at registration.
+	 *
+	 * Cached so the input/output schema and the executed result derive from the exact same
+	 * structure, and {@see get_registered_settings()} is only walked once per request.
+	 *
+	 * @since 7.1.0
+	 * @var array<string, array{option: string, group: string, default: mixed, schema: array<string, mixed>}>|null
+	 */
+	private static $exposed_settings = null;
+
+	/**
+	 * Registers all settings abilities.
+	 *
+	 * Must run on the `wp_abilities_api_init` hook.
+	 *
+	 * @since 7.1.0
+	 */
+	public static function register(): void {
+		self::register_get_settings();
+
+		/*
+		 * A future write-oriented ability can be registered here, reusing the shared
+		 * helpers below (get_exposed_settings(), value_schema(), cast_value()):
+		 *
+		 *     self::register_manage_settings();
+		 */
+	}
+
+	/**
+	 * Registers the read-only `core/settings` ability.
+	 *
+	 * @since 7.1.0
+	 */
+	public static function register_get_settings(): void {
+		// Compute once; execute_get_settings() reuses this exact structure.
+		self::$exposed_settings = self::get_exposed_settings();
+
+		$settings    = self::$exposed_settings;
+		$field_names = array_keys( $settings );
+		$groups      = array();
+		$properties  = array();
+		foreach ( $settings as $exposed_name => $setting ) {
+			$properties[ $exposed_name ] = $setting['schema'];
+			if ( '' === $setting['group'] || in_array( $setting['group'], $groups, true ) ) {
+				continue;
+			}
+			$groups[] = $setting['group'];
+		}
+
+		wp_register_ability(
+			'core/settings',
+			array(
+				'label'               => __( 'Get Settings' ),
+				'description'         => __( 'Returns WordPress settings as a flat map of setting name to value. By default returns all settings exposed to abilities, or optionally a subset filtered by settings group, by setting name, or both.' ),
+				'category'            => self::CATEGORY,
+				'input_schema'        => self::get_settings_input_schema( $groups, $field_names ),
+				'output_schema'       => array(
+					'type'                 => 'object',
+					'description'          => __( 'A map of setting name to its current value.' ),
+					'properties'           => $properties,
+					'additionalProperties' => false,
+				),
+				'execute_callback'    => array( self::class, 'execute_get_settings' ),
+				'permission_callback' => array( self::class, 'has_permission' ),
+				'meta'                => array(
+					'annotations'  => array(
+						'readonly'    => true,
+						'destructive' => false,
+						'idempotent'  => true,
+					),
+					'show_in_rest' => true,
+				),
+			)
+		);
+	}
+
+	/**
+	 * Executes the `core/settings` ability.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param mixed $input Optional. The ability input. Default empty array.
+	 * @return array<string, mixed> Map of exposed setting name to current value.
+	 */
+	public static function execute_get_settings( $input = array() ): array {
+		$input = is_array( $input ) ? $input : array();
+
+		$settings = self::$exposed_settings;
+		if ( null === $settings ) {
+			// The cache is populated in register_get_settings() before the ability is
+			// registered, so this is unreachable in practice; bail defensively otherwise.
+			return array();
+		}
+
+		$group  = isset( $input['group'] ) && is_string( $input['group'] ) ? $input['group'] : '';
+		$fields = isset( $input['fields'] ) && is_array( $input['fields'] ) ? $input['fields'] : array();
+
+		$result = array();
+		foreach ( $settings as $exposed_name => $setting ) {
+			if ( '' !== $group && $setting['group'] !== $group ) {
+				continue;
+			}
+			if ( ! empty( $fields ) && ! in_array( $exposed_name, $fields, true ) ) {
+				continue;
+			}
+
+			$type  = isset( $setting['schema']['type'] ) && is_string( $setting['schema']['type'] ) ? $setting['schema']['type'] : 'string';
+			$value = get_option( $setting['option'], $setting['default'] );
+
+			$result[ $exposed_name ] = self::cast_value( $value, $type );
+		}
+
+		return $result;
+	}
+
+	/**
+	 * Checks whether the current user may use the settings abilities.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @return bool True if the current user can manage options.
+	 */
+	public static function has_permission(): bool {
+		return current_user_can( 'manage_options' );
+	}
+
+	/**
+	 * Builds the input schema for the get ability: optional filters by group and/or name.
+	 *
+	 * Both `group` and `fields` are optional; supplying both narrows the response to their
+	 * intersection, and supplying neither returns every exposed setting.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param list<string> $groups      Available settings groups.
+	 * @param list<string> $field_names Available exposed setting names.
+	 * @return array<string, mixed> The input JSON Schema.
+	 */
+	protected static function get_settings_input_schema( array $groups, array $field_names ): array {
+		return array(
+			'type'                 => 'object',
+			// Object (not array()) so the serialized schema default is {}, consistent with type:object.
+			'default'              => (object) array(),
+			'properties'           => array(
+				'group'  => array(
+					'type'        => 'string',
+					'enum'        => $groups,
+					'description' => __( 'Return only settings that belong to this settings group.' ),
+				),
+				'fields' => array(
+					'type'        => 'array',
+					'items'       => array(
+						'type' => 'string',
+						'enum' => $field_names,
+					),
+					'description' => __( 'Return only the settings with these names.' ),
+				),
+			),
+			'additionalProperties' => false,
+		);
+	}
+
+	/**
+	 * Returns the settings exposed through the Abilities API.
+	 *
+	 * Reads {@see get_registered_settings()} and keeps only settings flagged with a truthy
+	 * `show_in_abilities` argument. Each entry is keyed by its exposed name and carries the
+	 * underlying option name, the settings group, the registration default, and a JSON Schema
+	 * describing the value.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @return array<string, array{option: string, group: string, default: mixed, schema: array<string, mixed>}> Settings keyed by exposed name.
+	 */
+	protected static function get_exposed_settings(): array {
+		$settings = array();
+
+		foreach ( get_registered_settings() as $option_name => $args ) {
+			$show = $args['show_in_abilities'] ?? false;
+			if ( empty( $show ) ) {
+				continue;
+			}
+
+			$option_name  = (string) $option_name;
+			$exposed_name = is_array( $show ) && isset( $show['name'] ) && is_string( $show['name'] ) && '' !== $show['name'] ? $show['name'] : $option_name;
+
+			$settings[ $exposed_name ] = array(
+				'option'  => $option_name,
+				'group'   => isset( $args['group'] ) && is_string( $args['group'] ) ? $args['group'] : '',
+				'default' => array_key_exists( 'default', $args ) ? $args['default'] : false,
+				'schema'  => self::value_schema( $args, $show ),
+			);
+		}
+
+		return $settings;
+	}
+
+	/**
+	 * Builds the JSON Schema describing a single setting's value.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param array<string, mixed>      $args The setting registration arguments.
+	 * @param bool|array<string, mixed> $show The setting's `show_in_abilities` value.
+	 * @return array<string, mixed> The value JSON Schema.
+	 */
+	protected static function value_schema( array $args, $show ): array {
+		$schema = array(
+			'type' => isset( $args['type'] ) && is_string( $args['type'] ) ? $args['type'] : 'string',
+		);
+		if ( ! empty( $args['label'] ) ) {
+			$schema['title'] = $args['label'];
+		}
+		if ( ! empty( $args['description'] ) ) {
+			$schema['description'] = $args['description'];
+		}
+		if ( is_array( $show ) && isset( $show['schema'] ) && is_array( $show['schema'] ) ) {
+			/** @var array<string, mixed> $show_schema */
+			$show_schema = $show['schema'];
+			$schema      = array_merge( $schema, $show_schema );
+		}
+
+		return $schema;
+	}
+
+	/**
+	 * Casts a stored option value to the type declared in its settings registration.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param mixed  $value The raw option value.
+	 * @param string $type  The registered setting type.
+	 * @return mixed The value cast to the declared type.
+	 */
+	protected static function cast_value( $value, string $type ) {
+		switch ( $type ) {
+			case 'boolean':
+				return (bool) $value;
+			case 'integer':
+				return is_scalar( $value ) ? (int) $value : 0;
+			case 'number':
+				return is_scalar( $value ) ? (float) $value : 0.0;
+			case 'array':
+				return is_array( $value ) ? $value : array();
+			case 'object':
+				// Cast to object so an empty/non-array value serializes as {} (not []) and
+				// satisfies the `object` output schema validated by execute().
+				return (object) ( is_array( $value ) ? $value : array() );
+			default:
+				return is_scalar( $value ) ? (string) $value : $value;
+		}
+	}
+}