How to regulate access to static files in express?

Question

Express.js

The site is a school of online courses. There are several courses, inside which there are mp4 and pdf files. The files are located in the files folder. I gave them access via express.static(): But I'm worried that a person who does not have access to subscription B will be able to open pdf and audio files through the address bar. Is there any way to check if a person has access to a subscription, and thus secure the files?
app.use('/files', express.static('files'))

Answer 1

It is better to /files/:filenamehang up on the handler and check the subscription there. And already give a file or a 403 error.