我的理解是，您希望对您的类别设置帖子数量限制，以便每个类别都有指定数量的帖子。很长一段时间后，我试图回答WordPress SE上的一个问题，所以我希望我能理解。

说明：类别没有元数据，因此您需要自己的自定义表来存储类别限制。对自定义表的读写应该在自定义元函数中进行抽象。例如get_post_count_limit. 一旦get和set函数就绪，那么您就可以连接到所需的WordPress操作（正如您提到的publish post，所以在下面的代码中，我使用了publish_post 操作）。

在连接到的函数中publish_post 操作中，您可以简单地循环分配给帖子的所有类别，使用自定义函数检查它们的限制，然后检查category\\u count属性。如果category\\u计数超过限制，只需获取最旧的帖子并从中删除category即可。

代码

<?php
/**
 * Plugin Name: Category Post Count Limit
 * Description: Allows to set limit on number of posts in a category
 * Author: Hameedullah Khan
 **/



add_action( \'publish_post\', \'cpcl_check_post_limit\' );
function cpcl_check_post_limit( $post_id ) {
    $cat_ids = wp_get_post_categories( $post_id );
    foreach( $cat_ids as $cat_id ) {
        $cat = get_category( $cat_id );
        $post_count_limit = get_post_count_limit( $cat_id );
        if ( $post_count_limit < 1 ) { // limit lower then 1 means unlimited.
            continue;
        }
        $category_count = $cat->category_count;
        if ( $category_count > $post_count_limit ) {
            $numposts = $category_count - $post_count_limit;
            $query = new WP_Query( array( \'category__in\' => array( $cat_id ), \'orderby\' => \'date\', \'posts_per_page\' => $numposts, \'order\' => \'ASC\' ) );
            while ($query->have_posts() ) {
                $query->next_post();
                $cp_cat_ids = wp_get_post_categories( $query->post->ID );
                unset( $cp_cat_ids[array_search( $cat_id, $cp_cat_ids )] );
                $cp_cat_ids = array_values( $cp_cat_ids );
                wp_set_post_categories( $query->post->ID, $cp_cat_ids );

            }
            wp_reset_postdata();
        }
    }
}

add_action( \'category_add_form_fields\', \'cpcl_field_add\', 10, 1);
function cpcl_field_add( $cat ) {
?>
    <div class="form-field">
        <label for="post-count">Post Count Limit</label><input type="text" name="post-count" type="text" /></label>
    </div>
<?php
}

add_action( \'category_edit_form_fields\', \'cpcl_field_edit\', 10, 1 );
function cpcl_field_edit( $cat ) {
    $post_count = get_post_count_limit( $cat->term_id );
?>
    <tr class="form-field">
        <th scope="row" valign="top">
            <label for="post-count">Post Count Limit</label>
        </th>
        <td>
            <input type="text" name="post-count" type="text" value="<?php echo $post_count; ?>" /></label>
        </td>
    </tr>
<?php
}


add_action( \'created_category\', \'cpcl_save_post_count_limit\', 10, 1 );
add_action( \'edited_category\', \'cpcl_save_post_count_limit\', 10, 1 );
function cpcl_save_post_count_limit( $cat_id ) {
    if (current_user_can( \'manage_categories\' ) && isset( $_POST[\'post-count\'] ) ) {
        $post_count_limit = ( int ) $_POST[\'post-count\'];
        update_post_count_limit( $cat_id, $post_count_limit );
    }

}

function get_post_count_limit( $cat_id, $return_null = false ) {
    global $wpdb;

    $table_name = $wpdb->prefix . \'cat_post_count_limit\';

    $cpcl_meta = $wpdb->get_row( "SELECT * FROM $table_name WHERE cat_id = $cat_id" );

    if ( ! $cpcl_meta ) {
        if ( $return_null && $cpcl_meta == null ) {
            return null;
        } else {
            return 0;
        }
    } else {
        return $cpcl_meta->post_count;
    }
}
function update_post_count_limit( $cat_id, $post_count_limit ) {
    global $wpdb;

    $table_name = $wpdb->prefix . \'cat_post_count_limit\';

    if ( get_post_count_limit( $cat_id, true) == null )  {
        $wpdb->insert( 
            $table_name, 
            array(
                \'cat_id\' => $cat_id,
                \'post_count\' => $post_count_limit
            ),
            array(
                \'%d\',
                \'%d\'
            )
        );
        return $wpdb->insert_id;
    } else {

        return $wpdb->update(
            $table_name,
            array(
                \'post_count\' => $post_count_limit
            ),
            array(
                \'cat_id\' => $cat_id
            ),
            array( \'%d\' ),
            array( \'%d\' )
        );
    }
}

function cpcl_initialize_categories() {
    global $wpdb;

    $table_name = $wpdb->prefix . \'cat_post_count_limit\';

    $sql = "CREATE TABLE IF NOT EXISTS `$table_name` (
        `cpcl_id` int(11) NOT NULL AUTO_INCREMENT,
        `cat_id` int(11) NOT NULL,
        `post_count` int(11) NOT NULL,
        PRIMARY KEY (`cpcl_id`)
    )";
    require_once( ABSPATH . \'wp-admin/includes/upgrade.php\' );
    dbDelta( $sql );
}
register_activation_hook( __FILE__, \'cpcl_initialize_categories\' );
?>

非常期待关于改进我的答案和/或代码的建议。