pingback

function do_all_pings() {
	global $wpdb;

	// Do pingbacks.
	$pings = get_posts(
		array(
			'post_type'        => get_post_types(),
			'suppress_filters' => false,
			'nopaging'         => true,
			'meta_key'         => '_pingme',
			'fields'           => 'ids',
		)
	);

	foreach ( $pings as $ping ) {
		delete_post_meta( $ping, '_pingme' );
		pingback( null, $ping );
	}

	// Do enclosures.
	$enclosures = get_posts(
		array(
			'post_type'        => get_post_types(),
			'suppress_filters' => false,
			'nopaging'         => true,
			'meta_key'         => '_encloseme',
			'fields'           => 'ids',
		)
	);

	foreach ( $enclosures as $enclosure ) {
		delete_post_meta( $enclosure, '_encloseme' );
		do_enclose( null, $enclosure );
	}

	// Do trackbacks.
	$trackbacks = get_posts(
		array(
			'post_type'        => get_post_types(),
			'suppress_filters' => false,
			'nopaging'         => true,
			'meta_key'         => '_trackbackme',
			'fields'           => 'ids',
		)
	);

	foreach ( $trackbacks as $trackback ) {
		delete_post_meta( $trackback, '_trackbackme' );
		do_trackbacks( $trackback );
	}

	// Do Update Services/Generic Pings.
	generic_ping();
}

/**
 * Perform trackbacks.
 *
 * @since 1.5.0
 * @since 4.7.0 `$post_id` can be a WP_Post object.
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int|WP_Post $post_id Post object or ID to do trackbacks on.
 */
function do_trackbacks( $post_id ) {
	global $wpdb;
	$post = get_post( $post_id );
	if ( ! $post ) {
		return false;
	}

	$to_ping = get_to_ping( $post );
	$pinged  = get_pung( $post );
	if ( empty( $to_ping ) ) {
		$wpdb->update( $wpdb->posts, array( 'to_ping' => '' ), array( 'ID' => $post->ID ) );
		return;
	}

	if ( empty( $post->post_excerpt ) ) {
		/** This filter is documented in wp-includes/post-template.php */
		$excerpt = apply_filters( 'the_content', $post->post_content, $post->ID );
	} else {
		/** This filter is documented in wp-includes/post-template.php */
		$excerpt = apply_filters( 'the_excerpt', $post->post_excerpt );
	}

	$excerpt = str_replace( ']]>', ']]>', $excerpt );
	$excerpt = wp_html_excerpt( $excerpt, 252, '…' );

	/** This filter is documented in wp-includes/post-template.php */
	$post_title = apply_filters( 'the_title', $post->post_title, $post->ID );
	$post_title = strip_tags( $post_title );

	if ( $to_ping ) {
		foreach ( (array) $to_ping as $tb_ping ) {