Expose theme_supports data through a minimial theme controller

lib/class-wp-rest-themes-controller.php

@@ -0,0 +1,251 @@
+<?php
+/**
+ * REST API: WP_REST_Themes_Controller class
+ *
+ * @package WordPress
+ * @subpackage REST_API
+ * @since 5.0.0
+ */
+
+/**
+ * Core class used to manage themes via the REST API.
+ *
+ * @since 5.0.0
+ *
+ * @see WP_REST_Controller
+ */
+class WP_REST_Themes_Controller extends WP_REST_Controller {
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 5.0.0
+	 */
+	public function __construct() {
+		$this->namespace = 'wp/v2';
+		$this->rest_base = 'themes';
+	}
+
+	/**
+	 * Registers the routes for the objects of the controller.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @see register_rest_route()
+	 */
+	public function register_routes() {
+		register_rest_route(
+			$this->namespace,
+			'/' . $this->rest_base,
+			array(
+				array(
+					'methods'             => WP_REST_Server::READABLE,
+					'callback'            => array( $this, 'get_items' ),
+					'permission_callback' => array( $this, 'get_items_permissions_check' ),
+					'args'                => $this->get_collection_params(),
+				),
+				'schema' => array( $this, 'get_item_schema' ),
+			)
+		);
+	}
+
+	/**
+	 * Checks if a given request has access to read the theme.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return true|WP_Error True if the request has read access for the item, otherwise WP_Error object.
+	 */
+	public function get_items_permissions_check( $request ) {
+		if ( ! is_user_logged_in() || ! current_user_can( 'edit_posts' ) ) {
+			return new WP_Error( 'rest_user_cannot_view', __( 'Sorry, you are not allowed to view themes.', 'gutenberg' ), array( 'status' => rest_authorization_required_code() ) );
+		}
+
+		return true;
+	}
+
+	/**
+	 * Retrieves a collection of themes.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
+	 */
+	public function get_items( $request ) {
+		// Retrieve the list of registered collection query parameters.
+		$registered = $this->get_collection_params();
+		$themes     = array();
+
+		if ( isset( $registered['status'], $request['status'] ) && in_array( 'active', $request['status'], true ) ) {
+			$active_theme = wp_get_theme();
+			$active_theme = $this->prepare_item_for_response( $active_theme, $request );
+			$themes[]     = $this->prepare_response_for_collection( $active_theme );
+		}
+
+		$response = rest_ensure_response( $themes );
+
+		$response->header( 'X-WP-Total', count( $themes ) );
+		$response->header( 'X-WP-TotalThemes', count( $themes ) );
+
+		return $response;
+	}
+
+	/**
+	 * Prepares a single theme output for response.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_Theme        $theme   Theme object.
+	 * @param WP_REST_Request $request Request object.
+	 * @return WP_REST_Response Response object.
+	 */
+	public function prepare_item_for_response( $theme, $request ) {
+		$data   = array();
+		$fields = $this->get_fields_for_response( $request );
+
+		if ( in_array( 'theme_supports', $fields, true ) ) {
+			$formats                           = get_theme_support( 'post-formats' );
+			$formats                           = is_array( $formats ) ? array_values( $formats[0] ) : array();
+			$formats                           = array_merge( array( 'standard' ), $formats );
+			$data['theme_supports']['formats'] = $formats;
+
+			$data['theme_supports']['post-thumbnails'] = false;
+			$post_thumbnails                           = get_theme_support( 'post-thumbnails' );
+
+			if ( $post_thumbnails ) {
+				// $post_thumbnails can contain a nested array of post types.
+				// e.g. array( array( 'post', 'page' ) ).
+				$data['theme_supports']['post-thumbnails'] = is_array( $post_thumbnails ) ? $post_thumbnails[0] : true;
+			}
+		}
+
+		$data = $this->add_additional_fields_to_object( $data, $request );
+
+		// Wrap the data in a response object.
+		$response = rest_ensure_response( $data );
+
+		$response->add_links( $this->prepare_links( $theme ) );
+
+		/**
+		 * Filters theme data returned from the REST API.
+		 *
+		 * @since 5.0.0
+		 *
+		 * @param WP_REST_Response $response The response object.
+		 * @param WP_Theme         $theme    Theme object used to create response.
+		 * @param WP_REST_Request  $request  Request object.
+		 */
+		return apply_filters( 'rest_prepare_theme', $response, $theme, $request );
+	}
+
+	/**
+	 * Prepares links for the theme request.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_Theme $theme Theme object.
+	 * @return array Links for the given theme.
+	 */
+	protected function prepare_links( $theme ) {
+		$links = array(
+			'self' => array(
+				'href' => rest_url( sprintf( '%s/%s?status=active', $this->namespace, $this->rest_base ) ),
+			),
+		);
+
+		return $links;
+	}
+
+	/**
+	 * Retrieves the theme's schema, conforming to JSON Schema.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @return array Item schema data.
+	 */
+	public function get_item_schema() {
+		$schema = array(
+			'$schema'    => 'http://json-schema.org/draft-04/schema#',
+			'title'      => 'theme',
+			'type'       => 'object',
+			'properties' => array(
+				'theme_supports' => array(
+					'description' => __( 'A list of features this theme supports.', 'gutenberg' ),
+					'type'        => 'array',
+					'readonly'    => true,
+					'properties'  => array(
+						'formats'         => array(
+							'description' => __( 'Post formats supported.', 'gutenberg' ),
+							'type'        => 'array',
+							'readonly'    => true,
+						),
+						'post-thumbnails' => array(
+							'description' => __( 'Whether the theme supports post thumbnails.', 'gutenberg' ),
+							'type'        => array( 'array', 'bool' ),
+							'readonly'    => true,
+						),
+					),
+				),
+			),
+		);
+
+		return $this->add_additional_fields_schema( $schema );
+	}
+
+	/**
+	 * Retrieves the search params for the themes collection.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @return array Collection parameters.
+	 */
+	public function get_collection_params() {
+		$query_params = parent::get_collection_params();
+
+		$query_params['status'] = array(
+			'description'       => __( 'Limit result set to themes assigned one or more statuses.', 'gutenberg' ),
+			'type'              => 'array',
+			'items'             => array(
+				'enum' => array( 'active' ),
+				'type' => 'string',
+			),
+			'required'          => true,
+			'sanitize_callback' => array( $this, 'sanitize_theme_status' ),
+		);
+
+		/**
+		 * Filter collection parameters for the themes controller.
+		 *
+		 * @since 5.0.0
+		 *
+		 * @param array        $query_params JSON Schema-formatted collection parameters.
+		 */
+		return apply_filters( 'rest_themes_collection_params', $query_params );
+	}
+
+	/**
+	 * Sanitizes and validates the list of theme status.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param  string|array    $statuses  One or more theme statuses.
+	 * @param  WP_REST_Request $request   Full details about the request.
+	 * @param  string          $parameter Additional parameter to pass to validation.
+	 * @return array|WP_Error A list of valid statuses, otherwise WP_Error object.
+	 */
+	public function sanitize_theme_status( $statuses, $request, $parameter ) {
+		$statuses = wp_parse_slug_list( $statuses );
+
+		foreach ( $statuses as $status ) {
+			$result = rest_validate_request_arg( $status, $request, $parameter );
+
+			if ( is_wp_error( $result ) ) {
+				return $result;
+			}
+		}
+
+		return $statuses;
+	}
+}

lib/client-assets.php

@@ -1304,6 +1304,7 @@ function gutenberg_editor_scripts_and_styles( $hook ) {
 		'/',
 		'/wp/v2/types?context=edit',
 		'/wp/v2/taxonomies?per_page=-1&context=edit',
+		'/wp/v2/themes?status=active',
 		sprintf( '/wp/v2/%s/%s?context=edit', $rest_base, $post->ID ),
 		sprintf( '/wp/v2/types/%s?context=edit', $post_type ),
 		sprintf( '/wp/v2/users/me?post_type=%s&context=edit', $post_type ),

lib/load.php

@@ -18,6 +18,9 @@
 	if ( ! class_exists( 'WP_REST_Autosaves_Controller' ) ) {
 		require dirname( __FILE__ ) . '/class-wp-rest-autosaves-controller.php';
 	}
+	if ( ! class_exists( 'WP_REST_Themes_Controller' ) ) {
+		require dirname( __FILE__ ) . '/class-wp-rest-themes-controller.php';
+	}
 	if ( ! class_exists( 'WP_REST_Block_Renderer_Controller' ) ) {
 		require dirname( __FILE__ ) . '/class-wp-rest-block-renderer-controller.php';
 	}
@@ -30,6 +33,7 @@
 	if ( ! class_exists( 'WP_REST_Post_Search_Handler' ) ) {
 		require dirname( __FILE__ ) . '/class-wp-rest-post-search-handler.php';
 	}
+
 	require dirname( __FILE__ ) . '/rest-api.php';
 }
 

lib/rest-api.php

@@ -45,6 +45,9 @@ function gutenberg_register_rest_routes() {
 		$autosaves_controller = new WP_REST_Autosaves_Controller( $post_type->name );
 		$autosaves_controller->register_routes();
 	}
+
+	$themes_controller = new WP_REST_Themes_Controller();
+	$themes_controller->register_routes();
 }
 add_action( 'rest_api_init', 'gutenberg_register_rest_routes' );
 
@@ -304,40 +307,6 @@ function gutenberg_register_taxonomy_prepare_functions( $taxonomy ) {
 }
 add_filter( 'registered_taxonomy', 'gutenberg_register_taxonomy_prepare_functions' );
 
-/**
- * Ensure that the wp-json index contains the 'theme-supports' setting as
- * part of its site info elements.
- *
- * @see https://core.trac.wordpress.org/ticket/45016
- *
- * @param WP_REST_Response $response WP REST API response of the wp-json index.
- * @return WP_REST_Response Response that contains theme-supports.
- */
-function gutenberg_ensure_wp_json_has_theme_supports( $response ) {
-	$site_info = $response->get_data();
-	if ( ! array_key_exists( 'theme_supports', $site_info ) ) {
-		$site_info['theme_supports'] = array();
-	}
-	if ( ! array_key_exists( 'formats', $site_info['theme_supports'] ) ) {
-		$formats = get_theme_support( 'post-formats' );
-		$formats = is_array( $formats ) ? array_values( $formats[0] ) : array();
-		$formats = array_merge( array( 'standard' ), $formats );
-
-		$site_info['theme_supports']['formats'] = $formats;
-	}
-	if ( ! array_key_exists( 'post-thumbnails', $site_info['theme_supports'] ) ) {
-		$post_thumbnails = get_theme_support( 'post-thumbnails' );
-		if ( $post_thumbnails ) {
-			// $post_thumbnails can contain a nested array of post types.
-			// e.g. array( array( 'post', 'page' ) ).
-			$site_info['theme_supports']['post-thumbnails'] = is_array( $post_thumbnails ) ? $post_thumbnails[0] : true;
-		}
-	}
-	$response->set_data( $site_info );
-	return $response;
-}
-add_filter( 'rest_index', 'gutenberg_ensure_wp_json_has_theme_supports' );
-
 /**
  * Handle any necessary checks early.
  *

packages/core-data/src/actions.js

@@ -69,14 +69,14 @@ export function receiveEntityRecords( kind, name, records, query ) {
 /**
  * Returns an action object used in signalling that the index has been received.
  *
- * @param {Object} index Index received.
+ * @param {Object} themeSupports Theme support for the current theme.
  *
  * @return {Object} Action object.
  */
-export function receiveThemeSupportsFromIndex( index ) {
+export function receiveThemeSupports( themeSupports ) {
 	return {
 		type: 'RECEIVE_THEME_SUPPORTS',
-		themeSupports: index.theme_supports,
+		themeSupports,
 	};
 }
 

packages/core-data/src/resolvers.js

@@ -14,7 +14,7 @@ import { addQueryArgs } from '@wordpress/url';
 import {
 	receiveUserQuery,
 	receiveEntityRecords,
-	receiveThemeSupportsFromIndex,
+	receiveThemeSupports,
 	receiveEmbedPreview,
 } from './actions';
 import { getKindEntities } from './entities';
@@ -70,8 +70,8 @@ export function* getEntityRecords( kind, name, query = {} ) {
  * Requests theme supports data from the index.
  */
 export function* getThemeSupports() {
-	const index = yield apiFetch( { path: '/' } );
-	yield receiveThemeSupportsFromIndex( index );
+	const activeThemes = yield apiFetch( { path: '/wp/v2/themes?status=active' } );
+	yield receiveThemeSupports( activeThemes[ 0 ].theme_supports );
 }
 
 /**