Php 为媒体添加新的mime类型

我想通过以下代码将一些dfxp文件上载到媒体：

if ( !function_exists('media_handle_upload') ) {
    require_once(ABSPATH . "wp-admin" . '/includes/image.php');
    require_once(ABSPATH . "wp-admin" . '/includes/file.php');
    require_once(ABSPATH . "wp-admin" . '/includes/media.php');
}



  $id = media_handle_sideload(array('name' =>'test.dfxp', 'tmp_name' =>****/test.dfxp' ));

但我得到了这个错误：

Sorry, this file type is not permitted for security reasons.

即使我将此函数放在代码上方以添加mime类型：

function custom_upload_mimes( $existing_mimes ) {
    // add webm to the list of mime types
    $existing_mimes['dfxp'] = 'application/dfxp';
    // return the array back to the function with our added mime type
    return $existing_mimes;
}
add_filter('upload_mimes', 'custom_upload_mimes');

是的，我查了一下哑剧，找到了

---

如何解决这个问题？

我不认为有所谓的“application/dfxp”mime类型。试试这个

$existing_mimes['dfxp'] = 'application/xml';

代替

$existing_mimes['dfxp'] = 'application/dfxp';