Site Editor: preload initial canvas data

backport-changelog/7.1/11766.md

@@ -0,0 +1,3 @@
+https://github.com/WordPress/wordpress-develop/pull/11766
+
+* https://github.com/WordPress/gutenberg/pull/78075

lib/compat/wordpress-7.1/preload.php

@@ -0,0 +1,149 @@
+<?php
+
+/**
+ * Preload Site Editor resources that are deterministic for the initial canvas.
+ *
+ * @param array                   $paths   REST API paths to preload.
+ * @param WP_Block_Editor_Context $context Current block editor context.
+ *
+ * @return array Filtered preload paths.
+ */
+function gutenberg_block_editor_preload_paths_7_1( $paths, $context ) {
+	if ( 'core/edit-site' !== $context->name ) {
+		return $paths;
+	}
+
+	$template_slugs = array();
+	$front_page     = null;
+	if ( ! empty( $context->post ) && 'page' === $context->post->post_type ) {
+		$template_slugs[] = empty( $context->post->post_name ) ? 'page' : 'page-' . $context->post->post_name;
+		$template_slugs[] = 'page';
+	} else {
+		$template_slugs[] = 'front-page';
+
+		$page_on_front = (int) get_option( 'page_on_front' );
+		if ( 'page' === get_option( 'show_on_front' ) && $page_on_front > 0 ) {
+			$front_page = get_post( $page_on_front );
+			if ( $front_page instanceof WP_Post ) {
+				$template_slugs[] = empty( $front_page->post_name ) ? 'page' : 'page-' . $front_page->post_name;
+				$template_slugs[] = 'page';
+			}
+		} else {
+			$template_slugs[] = 'home';
+		}
+
+		$template_slugs[] = 'index';
+	}
+
+	$template_slugs = array_values( array_unique( $template_slugs ) );
+	$templates      = get_block_templates(
+		array(
+			'slug__in' => $template_slugs,
+		),
+		'wp_template'
+	);
+	$priorities     = array_flip( $template_slugs );
+
+	usort(
+		$templates,
+		static function ( $template_a, $template_b ) use ( $priorities ) {
+			return ( $priorities[ $template_a->slug ] ?? 999 ) - ( $priorities[ $template_b->slug ] ?? 999 );
+		}
+	);
+
+	$template_part_ids = array();
+	$has_query         = false;
+
+	if ( ! empty( $templates ) && ! empty( $templates[0]->content ) ) {
+		$blocks = gutenberg_resolve_pattern_blocks( parse_blocks( $templates[0]->content ) );
+		if ( class_exists( 'WP_Block_Processor' ) ) {
+			$processor = new WP_Block_Processor( serialize_blocks( $blocks ) );
+			while ( $processor->next_block() ) {
+				if ( $processor->is_block_type( 'core/query' ) ) {
+					$has_query = true;
+				}
+
+				if ( ! $processor->is_block_type( 'core/template-part' ) ) {
+					continue;
+				}
+
+				$attrs = $processor->allocate_and_return_parsed_attributes();
+				if ( ! is_array( $attrs ) || empty( $attrs['slug'] ) ) {
+					continue;
+				}
+
+				$theme               = ! empty( $attrs['theme'] ) ? $attrs['theme'] : get_stylesheet();
+				$template_part_ids[] = $theme . '//' . $attrs['slug'];
+			}
+		} else {
+			$walk_blocks = static function ( array $blocks_to_walk ) use ( &$walk_blocks, &$template_part_ids, &$has_query ) {
+				foreach ( $blocks_to_walk as $block ) {
+					if ( 'core/template-part' === ( $block['blockName'] ?? '' ) && ! empty( $block['attrs']['slug'] ) ) {
+						$theme               = ! empty( $block['attrs']['theme'] ) ? $block['attrs']['theme'] : get_stylesheet();
+						$template_part_ids[] = $theme . '//' . $block['attrs']['slug'];
+					}
+
+					if ( 'core/query' === ( $block['blockName'] ?? '' ) ) {
+						$has_query = true;
+					}
+
+					if ( ! empty( $block['innerBlocks'] ) ) {
+						$walk_blocks( $block['innerBlocks'] );
+					}
+				}
+			};
+			$walk_blocks( $blocks );
+		}
+	}
+
+	foreach ( array_unique( $template_part_ids ) as $template_part_id ) {
+		$paths[] = '/wp/v2/template-parts/' . $template_part_id . '?context=edit';
+	}
+
+	if ( $front_page instanceof WP_Post ) {
+		$route_for_front_page = rest_get_route_for_post( $front_page );
+		if ( $route_for_front_page ) {
+			$paths[] = add_query_arg( 'context', 'edit', $route_for_front_page );
+		}
+		$paths[] = add_query_arg(
+			'slug',
+			empty( $front_page->post_name ) ? 'page' : 'page-' . $front_page->post_name,
+			'/wp/v2/templates/lookup'
+		);
+		$paths[] = '/wp/v2/types/page?context=edit';
+	}
+
+	if ( $has_query ) {
+		$post_rest_route = rest_get_route_for_post_type_items( 'post' );
+		$paths[]         = '/wp/v2/types/post?context=edit';
+		foreach ( array( 10, 3 ) as $per_page ) {
+			$paths[] = add_query_arg(
+				array(
+					'context'       => 'edit',
+					'offset'        => 0,
+					'order'         => 'desc',
+					'orderby'       => 'date',
+					'per_page'      => $per_page,
+					'ignore_sticky' => 'false',
+				),
+				$post_rest_route
+			);
+		}
+	}
+
+	$paths[] = add_query_arg(
+		array(
+			'context'  => 'edit',
+			'per_page' => 100,
+			'_fields'  => 'id,link,menu_order,parent,title,type',
+			'orderby'  => 'menu_order',
+			'order'    => 'asc',
+		),
+		rest_get_route_for_post_type_items( 'page' )
+	);
+
+	$paths[] = '/wp/v2/taxonomies?context=view';
+
+	return $paths;
+}
+add_filter( 'block_editor_rest_api_preload_paths', 'gutenberg_block_editor_preload_paths_7_1', 10, 2 );

lib/load.php

@@ -124,6 +124,7 @@ function gutenberg_is_experiment_enabled( $name ) {
 
 // WordPress 7.1 compat.
 require __DIR__ . '/compat/wordpress-7.1/classic-block.php';
+require __DIR__ . '/compat/wordpress-7.1/preload.php';
 
 // Experimental features.
 require __DIR__ . '/experimental/block-editor-settings-mobile.php';