我编写了一个小插件，它不仅可以验证自定义帖子类型上的输入字段，还可以删除默认的管理通知，而不使用Javascript。

下面是一些代码

/验证筛选器

$title = $album->post_title;
if ( ! $title ) {
    $errors[\'title\'] = "The title is required";
}

// if we have errors lets setup some messages
if (! empty($errors)) {

    // we must remove this action or it will loop for ever
    remove_action(\'save_post\', \'album_save_post\');

    // save the errors as option
    update_option(\'album_errors\', $errors);

    // Change post from published to draft
    $album->post_status = \'draft\';

    // update the post
    wp_update_post( $album );

    // we must add back this action
    add_action(\'save_post\', \'album_save_post\');

    // admin_notice is create by a $_GET[\'message\'] with a number that wordpress uses to
    // display the admin message so we will add a filter for replacing default admin message with a redirect
    add_filter( \'redirect_post_location\', \'album_post_redirect_filter\' );
}

何时save_post 运行时，它已将帖子保存在数据库中

然而，如果您需要验证ACF之外的内容，例如post\\u title，那么事情会变得更加复杂。

查看WordPress核心代码，尤其是wp-includes/post.php\'supdate_post() 函数，在将请求保存到数据库之前，没有内置的方法来拦截请求。

然而，我们可以钩住pre_post_update 和使用header() 和get_post_edit_link() 阻止保存帖子。

<?php

/**
*   Performs custom validation on custom post type "Site"
*/
function custom_post_site_save($post_id, $post_data) {
    # If this is just a revision, don\'t do anything.
    if (wp_is_post_revision($post_id))
        return;

    if ($post_data[\'post_type\'] == \'site\') {
        # In this example, we will raise an error for post titles with less than 5 characters
        if (strlen($post_data[\'post_title\']) < 5) {
            # Add a notification
            update_option(\'my_notifications\', json_encode(array(\'error\', \'Post title can\\\'t be less than 5 characters.\')));
            # And redirect
            header(\'Location: \'.get_edit_post_link($post_id, \'redirect\'));
            exit;
        }
    }
}
add_action( \'pre_post_update\', \'custom_post_site_save\', 10, 2);

/**
*   Shows custom notifications on wordpress admin panel
*/
function my_notification() {
    $notifications = get_option(\'my_notifications\');

    if (!empty($notifications)) {
        $notifications = json_decode($notifications);
        #notifications[0] = (string) Type of notification: error, updated or update-nag
        #notifications[1] = (string) Message
        #notifications[2] = (boolean) is_dismissible?
        switch ($notifications[0]) {
            case \'error\': # red
            case \'updated\': # green
            case \'update-nag\': # ?
                $class = $notifications[0];
                break;
            default:
                # Defaults to error just in case
                $class = \'error\';
                break;
        }

        $is_dismissable = \'\';
        if (isset($notifications[2]) && $notifications[2] == true)
            $is_dismissable = \'is_dismissable\';

        echo \'<div class="\'.$class.\' notice \'.$is_dismissable.\'">\';
           echo \'<p>\'.$notifications[1].\'</p>\';
        echo \'</div>\';

        # Let\'s reset the notification
        update_option(\'my_notifications\', false);
    }
}
add_action( \'admin_notices\', \'my_notification\' );

我只想补充一下@Lucas Bustamante的优秀答案，自定义字段的值可以通过$_POST 全球的

因此，如果验证引用自定义字段，@Lucas Bustamante answer也是有效的。例如：

<?php

/**
*   Performs custom validation on custom post type "Site"
*/
function custom_post_site_save($post_id, $post_data) {
    # If this is just a revision, don\'t do anything.
    if (wp_is_post_revision($post_id))
        return;

    if ($post_data[\'post_type\'] == \'site\') {
        # In this example, we will raise an error for post titles with less than 5 characters
        if (strlen($_POST[\'zip_code\']) < 5) {
            # Add a notification
            update_option(\'my_notifications\', json_encode(array(\'error\', \'Zip code can\\\'t be less than 5 characters.\')));
            # And redirect
            header(\'Location: \'.get_edit_post_link($post_id, \'redirect\'));
            exit;
        }
    }
}
add_action( \'pre_post_update\', \'custom_post_site_save\', 10, 2);

/**
*   Shows custom notifications on wordpress admin panel
*/
function my_notification() {
    $notifications = get_option(\'my_notifications\');

    if (!empty($notifications)) {
        $notifications = json_decode($notifications);
        #notifications[0] = (string) Type of notification: error, updated or update-nag
        #notifications[1] = (string) Message
        #notifications[2] = (boolean) is_dismissible?
        switch ($notifications[0]) {
            case \'error\': # red
            case \'updated\': # green
            case \'update-nag\': # ?
                $class = $notifications[0];
                break;
            default:
                # Defaults to error just in case
                $class = \'error\';
                break;
        }

        $is_dismissable = \'\';
        if (isset($notifications[2]) && $notifications[2] == true)
            $is_dismissable = \'is_dismissable\';

        echo \'<div class="\'.$class.\' notice \'.$is_dismissable.\'">\';
           echo \'<p>\'.$notifications[1].\'</p>\';
        echo \'</div>\';

        # Let\'s reset the notification
        update_option(\'my_notifications\', false);
    }
}
add_action( \'admin_notices\', \'my_notification\' );
``

您可以使用；wp\\U insert\\U post\\U数据“；在将数据插入数据库之前过滤到修改器或检查数据

add_filter( \'wp_insert_post_data\', \'validate_posttypes\' );
function wpb_custom_excerpt($data) {
    str_starts_with($data[\'post_title\'],\'wp\')?$data[\'post_title\']=\'wp\'.$data[\'post_title\']:null;
    return $data;
}