context['postId'] ) ) { return ''; } if ( post_password_required( $block->context['postId'] ) ) { return; } $footnotes = get_post_meta( $block->context['postId'], 'footnotes', true ); if ( ! $footnotes ) { return; } $footnotes = json_decode( $footnotes, true ); if ( ! is_array( $footnotes ) || count( $footnotes ) === 0 ) { return ''; } $wrapper_attributes = get_block_wrapper_attributes(); $block_content = ''; foreach ( $footnotes as $footnote ) { $block_content .= sprintf( '
  • %2$s ↩︎
  • ', $footnote['id'], $footnote['content'] ); } return sprintf( '
      %2$s
    ', $wrapper_attributes, $block_content ); } /** * Registers the `core/footnotes` block on the server. * * @since 6.3.0 */ function register_block_core_footnotes() { foreach ( array( 'post', 'page' ) as $post_type ) { register_post_meta( $post_type, 'footnotes', array( 'show_in_rest' => true, 'single' => true, 'type' => 'string', ) ); } register_block_type_from_metadata( __DIR__ . '/footnotes', array( 'render_callback' => 'render_block_core_footnotes', ) ); } add_action( 'init', 'register_block_core_footnotes' ); /** * Saves the footnotes meta value to the revision. * * @since 6.3.0 * * @param int $revision_id The revision ID. */ function wp_save_footnotes_meta( $revision_id ) { $post_id = wp_is_post_revision( $revision_id ); if ( $post_id ) { $footnotes = get_post_meta( $post_id, 'footnotes', true ); if ( $footnotes ) { // Can't use update_post_meta() because it doesn't allow revisions. update_metadata( 'post', $revision_id, 'footnotes', wp_slash( $footnotes ) ); } } } add_action( 'wp_after_insert_post', 'wp_save_footnotes_meta' ); /** * Keeps track of the revision ID for "rest_after_insert_{$post_type}". * * @since 6.3.0 * * @global int $wp_temporary_footnote_revision_id The footnote revision ID. * * @param int $revision_id The revision ID. */ function wp_keep_footnotes_revision_id( $revision_id ) { global $wp_temporary_footnote_revision_id; $wp_temporary_footnote_revision_id = $revision_id; } add_action( '_wp_put_post_revision', 'wp_keep_footnotes_revision_id' ); /** * This is a specific fix for the REST API. The REST API doesn't update * the post and post meta in one go (through `meta_input`). While it * does fix the `wp_after_insert_post` hook to be called correctly after * updating meta, it does NOT fix hooks such as post_updated and * save_post, which are normally also fired after post meta is updated * in `wp_insert_post()`. Unfortunately, `wp_save_post_revision` is * added to the `post_updated` action, which means the meta is not * available at the time, so we have to add it afterwards through the * `"rest_after_insert_{$post_type}"` action. * * @since 6.3.0 * * @global int $wp_temporary_footnote_revision_id The footnote revision ID. * * @param WP_Post $post The post object. */ function wp_add_footnotes_revisions_to_post_meta( $post ) { global $wp_temporary_footnote_revision_id; if ( $wp_temporary_footnote_revision_id ) { $revision = get_post( $wp_temporary_footnote_revision_id ); if ( ! $revision ) { return; } $post_id = $revision->post_parent; // Just making sure we're updating the right revision. if ( $post->ID === $post_id ) { $footnotes = get_post_meta( $post_id, 'footnotes', true ); if ( $footnotes ) { // Can't use update_post_meta() because it doesn't allow revisions. update_metadata( 'post', $wp_temporary_footnote_revision_id, 'footnotes', wp_slash( $footnotes ) ); } } } } add_action( 'rest_after_insert_post', 'wp_add_footnotes_revisions_to_post_meta' ); add_action( 'rest_after_insert_page', 'wp_add_footnotes_revisions_to_post_meta' ); /** * Restores the footnotes meta value from the revision. * * @since 6.3.0 * * @param int $post_id The post ID. * @param int $revision_id The revision ID. */ function wp_restore_footnotes_from_revision( $post_id, $revision_id ) { $footnotes = get_post_meta( $revision_id, 'footnotes', true ); if ( $footnotes ) { update_post_meta( $post_id, 'footnotes', wp_slash( $footnotes ) ); } else { delete_post_meta( $post_id, 'footnotes' ); } } add_action( 'wp_restore_post_revision', 'wp_restore_footnotes_from_revision', 10, 2 ); /** * Adds the footnotes field to the revision. * * @since 6.3.0 * * @param array $fields The revision fields. * @return array The revision fields. */ function wp_add_footnotes_to_revision( $fields ) { $fields['footnotes'] = __( 'Footnotes' ); return $fields; } add_filter( '_wp_post_revision_fields', 'wp_add_footnotes_to_revision' ); /** * Gets the footnotes field from the revision. * * @since 6.3.0 * * @param string $revision_field The field value, but $revision->$field * (footnotes) does not exist. * @param string $field The field name, in this case "footnotes". * @param object $revision The revision object to compare against. * @return string The field value. */ function wp_get_footnotes_from_revision( $revision_field, $field, $revision ) { return get_metadata( 'post', $revision->ID, $field, true ); } add_filter( '_wp_post_revision_field_footnotes', 'wp_get_footnotes_from_revision', 10, 3 ); /** * The REST API autosave endpoint doesn't save meta, so we can use the * `wp_creating_autosave` when it updates an exiting autosave, and * `_wp_put_post_revision` when it creates a new autosave. * * @since 6.3.0 * * @param int|array $autosave The autosave ID or array. */ function _wp_rest_api_autosave_meta( $autosave ) { // Ensure it's a REST API request. if ( ! defined( 'REST_REQUEST' ) || ! REST_REQUEST ) { return; } $body = rest_get_server()->get_raw_data(); $body = json_decode( $body, true ); if ( ! isset( $body['meta']['footnotes'] ) ) { return; } // `wp_creating_autosave` passes the array, // `_wp_put_post_revision` passes the ID. $id = is_int( $autosave ) ? $autosave : $autosave['ID']; if ( ! $id ) { return; } update_post_meta( $id, 'footnotes', wp_slash( $body['meta']['footnotes'] ) ); } // See https://github.com/WordPress/wordpress-develop/blob/2103cb9966e57d452c94218bbc3171579b536a40/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php#L391C1-L391C1. add_action( 'wp_creating_autosave', '_wp_rest_api_autosave_meta' ); // See https://github.com/WordPress/wordpress-develop/blob/2103cb9966e57d452c94218bbc3171579b536a40/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php#L398. // Then https://github.com/WordPress/wordpress-develop/blob/2103cb9966e57d452c94218bbc3171579b536a40/src/wp-includes/revision.php#L367. add_action( '_wp_put_post_revision', '_wp_rest_api_autosave_meta' ); /** * This is a workaround for the autosave endpoint returning early if the * revision field are equal. The problem is that "footnotes" is not real * revision post field, so there's nothing to compare against. * * This trick sets the "footnotes" field (value doesn't matter), which will * cause the autosave endpoint to always update the latest revision. That should * be fine, it should be ok to update the revision even if nothing changed. Of * course, this is temporary fix. * * @since 6.3.0 * * @param WP_Post $prepared_post The prepared post object. * @param WP_REST_Request $request The request object. * * See https://github.com/WordPress/wordpress-develop/blob/2103cb9966e57d452c94218bbc3171579b536a40/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php#L365-L384. * See https://github.com/WordPress/wordpress-develop/blob/2103cb9966e57d452c94218bbc3171579b536a40/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php#L219. */ function _wp_rest_api_force_autosave_difference( $prepared_post, $request ) { // We only want to be altering POST requests. if ( $request->get_method() !== 'POST' ) { return $prepared_post; } // Only alter requests for the '/autosaves' route. if ( substr( $request->get_route(), -strlen( '/autosaves' ) ) !== '/autosaves' ) { return $prepared_post; } $prepared_post->footnotes = '[]'; return $prepared_post; } add_filter( 'rest_pre_insert_post', '_wp_rest_api_force_autosave_difference', 10, 2 );