Allow view access of template rest endpoint to anyone with the edit_post capability

lib/compat/wordpress-6.6/class-gutenberg-rest-templates-controller-6-6.php

@@ -0,0 +1,70 @@
+<?php
+/**
+ * REST API: Gutenberg_REST_Templates_Controller_6_6 class
+ *
+ * @package    gutenberg
+ */
+
+/**
+ * Gutenberg_REST_Templates_Controller_6_6 class
+ *
+ * Templates and template parts currently only allow access to administrators with the
+ * `edit_theme_options` capability. In order to allow other roles to also view the templates,
+ * we need to override the permissions check for the REST API endpoints.
+ */
+class Gutenberg_REST_Templates_Controller_6_6 extends Gutenberg_REST_Templates_Controller_6_4 {
+
+	/**
+	 * Checks if a given request has access to read templates.
+	 *
+	 * @since 6.6
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return true|WP_Error True if the request has read access, WP_Error object otherwise.
+	 */
+	public function get_items_permissions_check( $request ) { // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable
+		if ( current_user_can( 'edit_posts' ) ) {
+			return true;
+		}
+		foreach ( get_post_types( array( 'show_in_rest' => true ), 'objects' ) as $post_type ) {
+			if ( current_user_can( $post_type->cap->edit_posts ) ) {
+				return true;
+			}
+		}
+
+		return new WP_Error(
+			'rest_cannot_manage_templates',
+			__( 'Sorry, you are not allowed to access the templates on this site.', 'default' ),
+			array(
+				'status' => rest_authorization_required_code(),
+			)
+		);
+	}
+
+	/**
+	 * Checks if a given request has access to read templates.
+	 *
+	 * @since 6.6
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return true|WP_Error True if the request has read access, WP_Error object otherwise.
+	 */
+	public function get_item_permissions_check( $request ) { // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable
+		if ( current_user_can( 'edit_posts' ) ) {
+			return true;
+		}
+		foreach ( get_post_types( array( 'show_in_rest' => true ), 'objects' ) as $post_type ) {
+			if ( current_user_can( $post_type->cap->edit_posts ) ) {
+				return true;
+			}
+		}
+
+		return new WP_Error(
+			'rest_cannot_manage_templates',
+			__( 'Sorry, you are not allowed to access the templates on this site.', 'default' ),
+			array(
+				'status' => rest_authorization_required_code(),
+			)
+		);
+	}
+}

lib/compat/wordpress-6.6/rest-api.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * PHP and WordPress configuration compatibility functions for the Gutenberg
+ * editor plugin changes related to REST API.
+ *
+ * @package gutenberg
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	die( 'Silence is golden.' );
+}
+
+if ( ! function_exists( 'wp_api_template_access_controller' ) ) {
+	/**
+	 * Hook in to the template and template part post types and modify the
+	 * access control for the rest endpoint to allow lower user roles to access
+	 * the templates and template parts.
+	 *
+	 * @param array  $args Current registered post type args.
+	 * @param string $post_type Name of post type.
+	 *
+	 * @return array
+	 */
+	function wp_api_template_access_controller( $args, $post_type ) {
+		if ( 'wp_template' === $post_type || 'wp_template_part' === $post_type ) {
+			$args['rest_controller_class'] = 'Gutenberg_REST_Templates_Controller_6_6';
+		}
+		return $args;
+	}
+}
+add_filter( 'register_post_type_args', 'wp_api_template_access_controller', 10, 2 );

lib/load.php

@@ -127,6 +127,8 @@ function gutenberg_is_experiment_enabled( $name ) {
 // WordPress 6.6 compat.
 require __DIR__ . '/compat/wordpress-6.6/block-bindings/pattern-overrides.php';
 require __DIR__ . '/compat/wordpress-6.6/option.php';
+require __DIR__ . '/compat/wordpress-6.6/class-gutenberg-rest-templates-controller-6-6.php';
+require __DIR__ . '/compat/wordpress-6.6/rest-api.php';
 
 // Experimental features.
 require __DIR__ . '/experimental/block-editor-settings-mobile.php';