do_trackbacks( int|WP_Post $post_id )

执行跟踪。
Perform trackbacks.

目录锚点：#参数#返回#源码

参数（Parameters）

返回（Return）

无返回值

源码（Source）

/**
 * Perform trackbacks.
 *
 * @since 1.5.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int $post_id Post ID to do trackbacks on.
 */
function do_trackbacks($post_id) {
	global $wpdb;

	$post = get_post( $post_id );
	$to_ping = get_to_ping($post_id);
	$pinged  = get_pung($post_id);
	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 ) {
			$tb_ping = trim($tb_ping);
			if ( !in_array($tb_ping, $pinged) ) {
				trackback($tb_ping, $post_title, $excerpt, $post_id);
				$pinged[] = $tb_ping;
			} else {
				$wpdb->query( $wpdb->prepare("UPDATE $wpdb->posts SET to_ping = TRIM(REPLACE(to_ping, %s, '')) WHERE ID = %d", $tb_ping, $post_id) );
			}
		}
	}
}