(WIP) Add a new endpoint that exposes block editor settings through the REST API

lib/class-wp-rest-block-editor-settings-controller.php

@@ -0,0 +1,72 @@
+<?php
+/**
+ * REST API: WP_REST_Block_Editor_Settings_Controller class
+ *
+ * @package    WordPress
+ * @subpackage REST_API
+ */
+
+/**
+ * Core class used to retrieve block editor settings via the REST API.
+ *
+ * @see WP_REST_Controller
+ */
+class WP_REST_Block_Editor_Settings_Controller extends WP_REST_Controller {
+	/**
+	 * Constructs the controller.
+	 */
+	public function __construct() {
+		$this->namespace = 'wp/v2';//'__experimental';
+		$this->rest_base = 'block-editor-settings';
+	}
+
+	/**
+	 * Registers the necessary REST API routes.
+	 */
+	public function register_routes() {
+		register_rest_route(
+			$this->namespace,
+			'/' . $this->rest_base,
+			array(
+				array(
+					'methods'             => WP_REST_Server::READABLE,
+					'callback'            => array( $this, 'get_settings' ),
+					'permission_callback' => array( $this, 'get_settings_permissions_check' )
+				)
+			)
+		);
+	}
+
+	/**
+	 * Checks whether a given request has permission to read block editor settings
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 *
+	 * @return WP_Error|bool True if the request has permission, WP_Error object otherwise.
+	 */
+	public function get_settings_permissions_check( $request ) {
+		if ( ! current_user_can( 'edit_post', $request['id'] ) ) {
+			$error = __( 'Sorry, you are not allowed to read the block editor settings.', 'gutenberg' );
+			return new WP_Error( 'rest_cannot_read_settings', $error, array( 'status' => rest_authorization_required_code() ) );
+		}
+
+		return true;
+	}
+
+	/**
+	 * Return all block editor settings
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 *
+	 * @return WP_Error|WP_REST_Response Response object on success, or WP_Error object on failure.
+	 */
+	public function get_settings( $request ) {
+		$settings = apply_filters( 'block_editor_settings', [] );
+
+		return rest_ensure_response( $settings );
+	}
+}

lib/global-styles.php

@@ -685,13 +685,7 @@ function gutenberg_experimental_global_styles_settings( $settings ) {
 	// The client needs some information to be able to access/update the user styles.
 	// We only do this if the theme has support for theme.json, though,
 	// as an indicator that the theme will know how to combine this with its stylesheet.
-	$screen = get_current_screen();
-	if (
-		! empty( $screen ) &&
-		function_exists( 'gutenberg_is_edit_site_page' ) &&
-		gutenberg_is_edit_site_page( $screen->id ) &&
-		gutenberg_experimental_global_styles_has_theme_json_support()
-	) {
+	if ( gutenberg_experimental_global_styles_has_theme_json_support() ) {
 		$settings['__experimentalGlobalStylesUserEntityId'] = gutenberg_experimental_global_styles_get_user_cpt_id();
 		$settings['__experimentalGlobalStylesContexts']     = gutenberg_experimental_global_styles_get_block_data();
 		$settings['__experimentalGlobalStylesBaseStyles']   = gutenberg_experimental_global_styles_merge_trees(

lib/load.php

@@ -38,6 +38,9 @@ function gutenberg_is_experiment_enabled( $name ) {
 	if ( ! class_exists( 'WP_REST_Block_Directory_Controller' ) ) {
 		require dirname( __FILE__ ) . '/class-wp-rest-block-directory-controller.php';
 	}
+	if ( ! class_exists( 'WP_REST_Block_Editor_Settings_Controller' ) ) {
+		require dirname( __FILE__ ) . '/class-wp-rest-block-editor-settings-controller.php';
+	}
 	if ( ! class_exists( 'WP_REST_Block_Types_Controller' ) ) {
 		require dirname( __FILE__ ) . '/class-wp-rest-block-types-controller.php';
 	}

lib/rest-api.php

@@ -152,6 +152,15 @@ function gutenberg_register_rest_block_directory() {
 }
 add_filter( 'rest_api_init', 'gutenberg_register_rest_block_directory' );
 
+/**
+ * Registers the Block types REST API routes.
+ */
+function gutenberg_register_rest_block_editor_settings() {
+	$editor_settings = new WP_REST_Block_Editor_Settings_Controller();
+	$editor_settings->register_routes();
+}
+add_action( 'rest_api_init', 'gutenberg_register_rest_block_editor_settings' );
+
 /**
  * Registers the Block types REST API routes.
  */