PHP：如何阻止对文件的直接URL访问，但是仍然允许登录用户下载它？

I have a website where users should be able to log in and listen to a song (a self-created mp3). I want to make it so the logged in user can listen/download/whatever, and the file should reside on the server (not be stored in the MySQL database), but not be able to be accessed by non-users who have the path to the URL.I have a website where users should be able to