Block Library: Add a Post Excerpt block.

lib/blocks.php

@@ -56,6 +56,7 @@ function gutenberg_reregister_core_block_types() {
 		'template-part.php'   => 'core/template-part',
 		'post-title.php'      => 'core/post-title',
 		'post-content.php'    => 'core/post-content',
+		'post-excerpt.php'    => 'core/post-excerpt',
 	);
 
 	$registry = WP_Block_Type_Registry::get_instance();

packages/block-library/src/index.js

@@ -68,6 +68,7 @@ import * as siteTitle from './site-title';
 import * as templatePart from './template-part';
 import * as postTitle from './post-title';
 import * as postContent from './post-content';
+import * as postExcerpt from './post-excerpt';
 
 /**
  * Function to register an individual block.
@@ -187,7 +188,7 @@ export const __experimentalRegisterExperimentalCoreBlocks =
 
 				// Register Full Site Editing Blocks.
 				...( __experimentalEnableFullSiteEditing ?
-					[ siteTitle, templatePart, postTitle, postContent ] :
+					[ siteTitle, templatePart, postTitle, postContent, postExcerpt ] :
 					[] ),
 			].forEach( registerBlock );
 		} :

packages/block-library/src/post-excerpt/block.json

@@ -0,0 +1,4 @@
+{
+	"name": "core/post-excerpt",
+	"category": "layout"
+}

packages/block-library/src/post-excerpt/edit.js

@@ -0,0 +1,17 @@
+/**
+ * WordPress dependencies
+ */
+import { useEntityProp, useEntityId } from '@wordpress/core-data';
+import { PlainText } from '@wordpress/block-editor';
+
+function PostExcerptDisplay() {
+	const [ excerpt, setExcerpt ] = useEntityProp( 'postType', 'post', 'excerpt' );
+	return <PlainText value={ excerpt } onChange={ setExcerpt } />;
+}
+
+export default function PostExcerptEdit() {
+	if ( ! useEntityId( 'postType', 'post' ) ) {
+		return 'Post Excerpt Placeholder';
+	}
+	return <PostExcerptDisplay />;
+}

packages/block-library/src/post-excerpt/index.js

@@ -0,0 +1,18 @@
+/**
+ * WordPress dependencies
+ */
+import { __ } from '@wordpress/i18n';
+
+/**
+ * Internal dependencies
+ */
+import metadata from './block.json';
+import edit from './edit';
+
+const { name } = metadata;
+export { metadata, name };
+
+export const settings = {
+	title: __( 'Post Excerpt' ),
+	edit,
+};

packages/block-library/src/post-excerpt/index.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * Server-side rendering of the `core/post-excerpt` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/post-excerpt` block on the server.
+ *
+ * @return string Returns the filtered post excerpt for the current post wrapped inside "p" tags.
+ */
+function render_block_core_post_excerpt() {
+	$post = gutenberg_get_post_from_context();
+	if ( ! $post ) {
+		return '';
+	}
+	return '<p>' . get_the_excerpt( $post ) . '</p>';
+}
+
+/**
+ * Registers the `core/post-excerpt` block on the server.
+ */
+function register_block_core_post_excerpt() {
+	register_block_type(
+		'core/post-excerpt',
+		array(
+			'render_callback' => 'render_block_core_post_excerpt',
+		)
+	);
+}
+add_action( 'init', 'register_block_core_post_excerpt' );