在以前的情况下，我可以为帖子添加自定义元字段，代码如下：

function website_add_meta_box() {
    add_meta_box(
        \'website-website\',
        __(\'Website\', \'website\'),
        \'website_html\',
        \'post\',
        \'normal\',
        \'default\'
    );
}
add_action(\'add_meta_boxes\', \'website_add_meta_box\');

function website_html($post) {
    wp_nonce_field(\'_website_nonce\', \'website_nonce\'); ?>

    <p>Information about users website.</p>

    <p>
        <label for="website_website_url"><?php _e(\'Website URL\', \'website\'); ?></label><br>
        <input type="text" name="website_website_url" id="website_website_url" value="<?php echo website_get_meta(\'website_website_url\'); ?>">
    </p>
    <p>
        <label for="website_website_source_code"><?php _e(\'Website Source Code\', \'website\'); ?></label><br>
        <textarea name="website_website_source_code" id="website_website_source_code" ><?php echo website_get_meta(\'website_website_source_code\'); ?></textarea>
    </p><?php
}

function website_save($post_id) {
    if (defined(\'DOING_AUTOSAVE\') && DOING_AUTOSAVE) return;
    if (!isset($_POST[\'website_nonce\']) || !wp_verify_nonce($_POST[\'website_nonce\'], \'_website_nonce\' )) return;
    if (!current_user_can(\'edit_post\', $post_id)) return;

    if (isset($_POST[\'website_website_url\']))
        update_post_meta($post_id, \'website_website_url\', esc_attr($_POST[\'website_website_url\']));
    if (isset($_POST[\'website_website_source_code\']))
        update_post_meta($post_id, \'website_website_source_code\', esc_attr($_POST[\'website_website_source_code\']));
}
add_action(\'save_post\', \'website_save\');