如何为单个文件上传器脚本设置不同于.ini的最大_file_size

How to set a different max_file_size other than that of the .ini for a single file uploader script

假设我将max_file_size设置为20mb，但我只想在特定文件中将其限制为4mb，我该如何实现这一点？

$default_max_file_size = ini_get('upload_max_filesize');
if ($is_special_file) {
   ini_set('upload_max_filesize', '4M');
   // process your file
   // set it back to original value
   ini_set('upload_max_filesize', $default_max_file_size);
}