像bueltge提到的那样，您需要注册自定义元字段并向api公开。最近，当我试图为我们的用户获取自定义元字段时，我遇到了这个问题。我认为我的解决方案将适用于您，如果您将其用于帖子和用户（请注意Register new field 第节）。法典文件也很有帮助。

// Extends user profiles with building_id field
function fb_add_custom_user_profile_fields( $user ) {
?>
    <table class="form-table">
        <tr>
            <th>
                <label for="building_id"><?php _e(\'Building ID\', \'your_textdomain\'); ?>
            </label></th>
            <td>
                <input type="text" name="building_id" id="building_id" value="<?php echo esc_attr( get_the_author_meta( \'building_id\', $user->ID ) ); ?>" class="regular-text" /><br />
                <span class="description"><?php _e(\'Please enter your building_id.\', \'your_textdomain\'); ?></span>
            </td>
        </tr>
    </table>
<?php }

function fb_save_custom_user_profile_fields( $user_id ) {
    if ( !current_user_can( \'edit_user\', $user_id ) )
        return FALSE;
    update_usermeta( $user_id, \'building_id\', $_POST[\'building_id\'] );
}

add_action( \'show_user_profile\', \'fb_add_custom_user_profile_fields\' );
add_action( \'edit_user_profile\', \'fb_add_custom_user_profile_fields\' );
add_action( \'personal_options_update\', \'fb_save_custom_user_profile_fields\' );
add_action( \'edit_user_profile_update\', \'fb_save_custom_user_profile_fields\' );

// Register new field (building _id) and expose it to WP REST API
// See docs:  https://developer.wordpress.org/reference/functions/register_rest_field/
add_action( \'rest_api_init\', \'create_api_users_meta_field\' );

function create_api_users_meta_field() {
    // Codex format example: register_rest_field ( \'name-of-post-type\', \'name-of-field-to-return\', array-of-callbacks-and-schema() )
    register_rest_field( \'user\', \'buidling_id\', array(
           \'get_callback\'    => \'get_user_meta_for_api\',
           \'schema\'          => null,
        )
    );
}

function get_user_meta_for_api( $object ) {
    //get the id of the user object array
    $user_id = $object[\'id\'];
    //return the user meta
    return get_user_meta( $user_id );
}