大致流程：当编辑的发布时间晚于服务器的当前时间时，系统会通过wp_schedule_single_event（）注册一个一次性的crontab脚本。
一：修改post的入口文件：wordpress\wp-admin\post.php
case 'editpost':
check_admin_referer( 'update-post_' . $post_id );
//修改post
$post_id = edit_post();
// Session cookie flag that the post was saved.
if ( isset( $_COOKIE['wp-saving-post'] ) && $_COOKIE['wp-saving-post'] === $post_id . '-check' ) {
setcookie( 'wp-saving-post', $post_id . '-saved', time() + DAY_IN_SECONDS, ADMIN_COOKIE_PATH, COOKIE_DOMAIN, is_ssl() );
}
redirect_post( $post_id ); // Send user on their way while we keep working.
exit;
二：修改post。wordpress\wp-admin\includes\post.php edit_post()->wp_update_post()
*****
add_meta( $post_ID );
update_post_meta( $post_ID, '_edit_last', get_current_user_id() );
//修改post
$success = wp_update_post( $translated );*****
三：处理好数据后，将数据更新到db。wordpress\wp-includes\post.php wp_update_post()->wp_insert_post()
*******
return wp_insert_post( $postarr, $wp_error );
}
四：更新db，插入数据后，触发hook。
*******
if ( 'attachment' !== $postarr['post_type'] ) {
//触发post状态变更后的hook
wp_transition_post_status( $data['post_status'], $previous_status, $post );
}
**********
五：wp_transition_post_status（）->do_action()
function wp_transition_post_status( $new_status, $old_status, $post ) {
do_action( 'transition_post_status', $new_status, $old_status, $post );
do_action( "{$old_status}_to_{$new_status}", $post );
//当为将来发布时：do_action("future_post", $post-> ID, $post)
do_action( "{$new_status}_{$post->post_type}", $post->ID, $post );}
六：触发future_post 并执行。
function _future_post_hook( $deprecated, $post ) {
//删除之前的hook
wp_clear_scheduled_hook( 'publish_future_post', array( $post->ID ) );
//注册cron
wp_schedule_single_event( strtotime( get_gmt_from_date( $post->post_date ) . ' GMT' ), 'publish_future_post', array( $post->ID ) );
}
七：使用wp-cli 查看cron。可以看到publish_future_post已经白注册到cron
+------------------------------------+---------------------+-----------------------+---------------+
| hook | next_run_gmt | next_run_relative | recurrence |
+------------------------------------+---------------------+-----------------------+---------------+
| publish_future_post | 2020-12-16 09:18:00 | 1 minute 11 seconds | Non-repeating |
| wp_privacy_delete_old_export_files | 2020-12-16 09:44:35 | 27 minutes 46 seconds | 1 hour |
| wp_version_check | 2020-12-16 14:44:35 | 5 hours 27 minutes | 12 hours |
| wp_update_plugins | 2020-12-16 14:44:35 | 5 hours 27 minutes | 12 hours |
| wp_update_themes | 2020-12-16 14:44:35 | 5 hours 27 minutes | 12 hours |
| recovery_mode_clean_expired_keys | 2020-12-17 02:44:35 | 17 hours 27 minutes | 1 day |
| wp_scheduled_delete | 2020-12-17 02:46:22 | 17 hours 29 minutes | 1 day |
| delete_expired_transients | 2020-12-17 02:46:22 | 17 hours 29 minutes | 1 day |
| wp_scheduled_auto_draft_delete | 2020-12-17 03:35:03 | 18 hours 18 minutes | 1 day |
| wsal_delete_logins | 2020-12-17 07:51:11 | 22 hours 34 minutes | 1 day |
| wsal_log_files_pruning | 2020-12-17 07:51:11 | 22 hours 34 minutes | 1 day |
| wpseo-reindex | 2020-12-17 08:30:35 | 23 hours 13 minutes | 1 day |
| wpseo_permalink_structure_check | 2020-12-17 08:30:35 | 23 hours 13 minutes | 1 day |
| wp_site_health_scheduled_check | 2020-12-23 02:44:35 | 6 days 17 hours | 1 week |
+------------------------------------+---------------------+-----------------------+---------------+
