[In progress] Add a Carousel block

carousel/.editorconfig

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+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+# WordPress Coding Standards
+# https://make.wordpress.org/core/handbook/coding-standards/
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = tab
+
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2

carousel/.gitignore

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+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Output of `npm pack`
+*.tgz
+
+# Output of `wp-scripts plugin-zip`
+*.zip
+
+# dotenv environment variables file
+.env

carousel/carousel.php

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+<?php
+/**
+ * Plugin Name:       Carousel
+ * Description:       Display a horizontal series of content.
+ * Version:           0.1.1
+ * Requires at least: 6.7
+ * Requires PHP:      8.0
+ * Author:            The WordPress Contributors
+ * Author URI:        https://wpspecialprojects.wordpress.com/
+ * Update URI:        https://opsoasis.wpspecialprojects.com/carousel/
+ * License:           GPL-2.0-or-later
+ * License URI:       https://www.gnu.org/licenses/gpl-2.0.html
+ * Text Domain:       carousel
+ *
+ * @package wpcomsp
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit; // Exit if accessed directly.
+}
+
+// If no other WPCOMSP Block Plugin added the self update class, add it.
+if ( ! class_exists( 'WPCOMSP_Blocks_Self_Update' ) ) {
+	require __DIR__ . '/classes/class-wpcomsp-blocks-self-update.php';
+
+	$wpcomsp_blocks_self_update = WPCOMSP_Blocks_Self_Update::get_instance();
+	$wpcomsp_blocks_self_update->hooks();
+}
+
+/**
+ * Setup auto-updates for this plugin from our monorepo.
+ * Done in an anonymous function for simplicity in making this a drop-in snippet.
+ *
+ * @param array $blocks Array of plugin files.
+ *
+ * @return array
+ */
+add_filter(
+	'wpcomsp_installed_blocks',
+	function ( $blocks ) {
+		$plugin_data = get_plugin_data( __FILE__ );
+
+		// Add the plugin slug here to enable autoupdates.
+		$blocks[] = 'carousel';
+
+		return $blocks;
+	}
+);
+
+/**
+ * Registers the block using a `blocks-manifest.php` file, which improves the performance of block type registration.
+ * Behind the scenes, it also registers all assets so they can be enqueued
+ * through the block editor in the corresponding context.
+ *
+ * @see https://make.wordpress.org/core/2025/03/13/more-efficient-block-type-registration-in-6-8/
+ * @see https://make.wordpress.org/core/2024/10/17/new-block-type-registration-apis-to-improve-performance-in-wordpress-6-7/
+ */
+function a8csp_carousel_block_init() {
+	/**
+	 * Registers the block(s) metadata from the `blocks-manifest.php` and registers the block type(s)
+	 * based on the registered block metadata.
+	 * Added in WordPress 6.8 to simplify the block metadata registration process added in WordPress 6.7.
+	 *
+	 * @see https://make.wordpress.org/core/2025/03/13/more-efficient-block-type-registration-in-6-8/
+	 */
+	if ( function_exists( 'wp_register_block_types_from_metadata_collection' ) ) {
+		wp_register_block_types_from_metadata_collection( __DIR__ . '/build', __DIR__ . '/build/blocks-manifest.php' );
+		return;
+	}
+
+	/**
+	 * Registers the block(s) metadata from the `blocks-manifest.php` file.
+	 * Added to WordPress 6.7 to improve the performance of block type registration.
+	 *
+	 * @see https://make.wordpress.org/core/2024/10/17/new-block-type-registration-apis-to-improve-performance-in-wordpress-6-7/
+	 */
+	if ( function_exists( 'wp_register_block_metadata_collection' ) ) {
+		wp_register_block_metadata_collection( __DIR__ . '/build', __DIR__ . '/build/blocks-manifest.php' );
+	}
+	/**
+	 * Registers the block type(s) in the `blocks-manifest.php` file.
+	 *
+	 * @see https://developer.wordpress.org/reference/functions/register_block_type/
+	 */
+	$manifest_data = require __DIR__ . '/build/blocks-manifest.php';
+	foreach ( array_keys( $manifest_data ) as $block_type ) {
+		register_block_type( __DIR__ . "/build/{$block_type}" );
+	}
+}
+add_action( 'init', 'a8csp_carousel_block_init' );

carousel/classes/class-wpcomsp-blocks-self-update.php

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+<?php
+/**
+ * Plugin Autoupdate Filter Self Update class.
+ * sets up autoupdates for this GitHub-hosted plugin.
+ *
+ * @package wpcomsp
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit; // Exit if accessed directly.
+}
+
+class WPCOMSP_Blocks_Self_Update {
+
+	public static $instance;
+
+	/**
+	 * Get instance of this class.
+	 *
+	 * @return WPCOMSP_Blocks_Self_Update
+	 */
+	public static function get_instance() {
+		if ( ! self::$instance ) {
+			self::$instance = new self();
+		}
+
+		return self::$instance;
+	}
+
+	/**
+	 * Initialize WordPress hooks
+	 */
+	public function hooks() {
+		add_filter( 'update_plugins_opsoasis.wpspecialprojects.com', array( $this, 'self_update' ), 10, 3 );
+	}
+
+	/**
+	 * Check for updates to this plugin
+	 *
+	 * @param array  $update   Array of update data.
+	 * @param array  $plugin_data Array of plugin data.
+	 * @param string $plugin_file Path to plugin file.
+	 *
+	 * @return array|bool Array of update data or false if no update available.
+	 */
+	public function self_update( $update, array $plugin_data, string $plugin_file ) {
+		// Already completed update check elsewhere.
+		if ( ! empty( $update ) ) {
+			return $update;
+		}
+
+		$plugin_filename_parts = explode( '/', $plugin_file );
+
+		// Ask opsoasis.mystagingwebsite.com if there's an update.
+		$response = wp_remote_get(
+			'https://opsoasis.wpspecialprojects.com/wp-json/opsoasis-blocks-version-manager/v1/update-check',
+			array(
+				'body' => array(
+					'plugin'  => $plugin_filename_parts[0],
+					'version' => $plugin_data['Version'],
+				),
+			)
+		);
+
+		// Bail if this plugin wasn't found on opsoasis.mystagingwebsite.com.
+		if ( 404 === wp_remote_retrieve_response_code( $response ) || 202 === wp_remote_retrieve_response_code( $response ) ) {
+			return $update;
+		}
+
+		$updated_version = wp_remote_retrieve_body( $response );
+		$updated_array   = json_decode( $updated_version, true );
+
+		// Validate JSON and required fields.
+		if ( ! is_array( $updated_array ) || ! isset( $updated_array['slug'], $updated_array['version'], $updated_array['package_url'] ) ) {
+			return $update;
+		}
+
+		return array(
+			'slug'    => $updated_array['slug'],
+			'version' => $updated_array['version'],
+			'url'     => $updated_array['package_url'],
+			'package' => $updated_array['package_url'],
+		);
+	}
+}