robotstxt-og/includes/class-robotstxt-og-meta-box.php

<?php
/**
 * Meta Box Class
 *
 * Provides per-post Open Graph and social media customization fields
 * in the WordPress post editor.
 *
 * @package ROBOTSTXT_OG
 * @since 1.2.0
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

/**
 * Class Robotstxt_OG_Meta_Box
 *
 * Registers and handles the Open Graph meta box in the post editor,
 * and registers the underlying post meta for REST API access.
 *
 * @since 1.2.0
 */
class Robotstxt_OG_Meta_Box {

	/**
	 * Initialize hooks.
	 *
	 * @since 1.2.0
	 *
	 * @return void
	 */
	public function init(): void {
		// Register post meta for REST API access (block editor).
		add_action( 'init', array( $this, 'register_post_meta' ) );

		// Meta box UI is admin-only.
		if ( is_admin() ) {
			add_action( 'add_meta_boxes', array( $this, 'register_meta_box' ) );
			add_action( 'save_post', array( $this, 'save_meta_box' ), 10, 2 );
		}
	}

	/**
	 * Register custom post meta for all public post types.
	 *
	 * Exposes _og_title and _og_description via the REST API so the
	 * block editor can read and write them via useEntityProp.
	 *
	 * @since 1.2.0
	 *
	 * @return void
	 */
	public function register_post_meta(): void {
		$post_types = get_post_types( array( 'public' => true ), 'names' );

		foreach ( $post_types as $post_type ) {
			register_post_meta(
				$post_type,
				'_og_title',
				array(
					'type'              => 'string',
					'single'            => true,
					'sanitize_callback' => 'sanitize_text_field',
					'auth_callback'     => static function () {
						return current_user_can( 'edit_posts' );
					},
					'show_in_rest'      => true,
				)
			);

			register_post_meta(
				$post_type,
				'_og_description',
				array(
					'type'              => 'string',
					'single'            => true,
					'sanitize_callback' => 'sanitize_textarea_field',
					'auth_callback'     => static function () {
						return current_user_can( 'edit_posts' );
					},
					'show_in_rest'      => true,
				)
			);
		}
	}

	/**
	 * Register the meta box for all public post types.
	 *
	 * @since 1.2.0
	 *
	 * @return void
	 */
	public function register_meta_box(): void {
		$post_types = get_post_types( array( 'public' => true ), 'names' );

		foreach ( $post_types as $post_type ) {
			add_meta_box(
				'robotstxt-og-meta-box',
				__( 'Open Graph / Social Media', 'robotstxt-og' ),
				array( $this, 'render_meta_box' ),
				$post_type,
				'normal',
				'default'
			);
		}
	}

	/**
	 * Render the meta box HTML.
	 *
	 * @since 1.2.0
	 *
	 * @param WP_Post $post The current post object.
	 * @return void
	 */
	public function render_meta_box( WP_Post $post ): void {
		wp_nonce_field( 'robotstxt_og_meta_box', 'robotstxt_og_meta_box_nonce' );

		$og_title       = (string) get_post_meta( $post->ID, '_og_title', true );
		$og_description = (string) get_post_meta( $post->ID, '_og_description', true );

		?>
		<table class="form-table" role="presentation">
			<tbody>
				<tr>
					<th scope="row">
						<label for="robotstxt_og_title">
							<?php esc_html_e( 'Custom Title', 'robotstxt-og' ); ?>
						</label>
					</th>
					<td>
						<input
							type="text"
							id="robotstxt_og_title"
							name="robotstxt_og_title"
							value="<?php echo esc_attr( $og_title ); ?>"
							class="large-text"
						/>
						<p class="description">
							<?php esc_html_e( 'Overrides the default og:title for this post. Leave blank to use the post title automatically.', 'robotstxt-og' ); ?>
						</p>
					</td>
				</tr>
				<tr>
					<th scope="row">
						<label for="robotstxt_og_description">
							<?php esc_html_e( 'Custom Description', 'robotstxt-og' ); ?>
						</label>
					</th>
					<td>
						<textarea
							id="robotstxt_og_description"
							name="robotstxt_og_description"
							class="large-text"
							rows="3"
						><?php echo esc_textarea( $og_description ); ?></textarea>
						<p class="description">
							<?php esc_html_e( 'Overrides the default og:description for this post. Leave blank to use the excerpt automatically.', 'robotstxt-og' ); ?>
						</p>
					</td>
				</tr>
			</tbody>
		</table>
		<?php
	}

	/**
	 * Save meta box values on post save.
	 *
	 * @since 1.2.0
	 *
	 * @param int     $post_id The post ID.
	 * @param WP_Post $post    The post object.
	 * @return void
	 */
	public function save_meta_box( int $post_id, WP_Post $post ): void {
		// Skip autosaves and revisions.
		if ( wp_is_post_autosave( $post_id ) || wp_is_post_revision( $post_id ) ) {
			return;
		}

		// Verify nonce.
		$nonce_raw = filter_input( INPUT_POST, 'robotstxt_og_meta_box_nonce', FILTER_SANITIZE_SPECIAL_CHARS );
		$nonce     = $nonce_raw ? sanitize_text_field( wp_unslash( $nonce_raw ) ) : '';

		if ( ! wp_verify_nonce( $nonce, 'robotstxt_og_meta_box' ) ) {
			return;
		}

		// Check permissions.
		$post_type_obj = get_post_type_object( $post->post_type );

		if ( ! $post_type_obj || ! current_user_can( $post_type_obj->cap->edit_post, $post_id ) ) {
			return;
		}

		// Save og:title.
		$og_title_raw = filter_input( INPUT_POST, 'robotstxt_og_title', FILTER_SANITIZE_SPECIAL_CHARS );
		$og_title     = $og_title_raw ? sanitize_text_field( wp_unslash( $og_title_raw ) ) : '';

		if ( empty( $og_title ) ) {
			delete_post_meta( $post_id, '_og_title' );
		} else {
			update_post_meta( $post_id, '_og_title', $og_title );
		}

		// Save og:description.
		$og_desc_raw = filter_input( INPUT_POST, 'robotstxt_og_description', FILTER_UNSAFE_RAW );
		$og_desc     = $og_desc_raw ? sanitize_textarea_field( wp_unslash( $og_desc_raw ) ) : '';

		if ( empty( $og_desc ) ) {
			delete_post_meta( $post_id, '_og_description' );
		} else {
			update_post_meta( $post_id, '_og_description', $og_desc );
		}
	}
}