[Bug]: E-books fail to load when using reverse proxy via subdirectory in 2.18.0

[nickpascucci]

What happened?

I updated my ABS installation to v2.18.0 and configured Caddy to point to it as a reverse proxy for the $SERVER_ROOT/audiobookshelf path. When opening an EPUB book I see a blank page. In the browser Network tab I see a failed request to the following path:

https://$SERVER_ROOT/api/items/9e3b549a-4c12-4ea2-b365-12a57df95f8d/ebook

Note that this path does not use the /audiobookshelf subdirectory prefix.

What did you expect to happen?

The EPUB should load. When accessing the same server using the 13378 port, the book loads successfully. In this case the request is still made without the prefix, but because there is no reverse proxy in the way it succeeds.

Steps to reproduce the issue

1. Configure a reverse proxy to target the /audiobookshelf subdirectory to an ABS v2.18.0 server.
2. Access the server through the reverse proxy using the /audiobookshelf subdirectory prefix.
3. Try to open an EPUB book.

Audiobookshelf version

v2.18.0

How are you running audiobookshelf?

Debian/PPA

What OS is your Audiobookshelf server hosted from?

Linux

If the issue is being seen in the UI, what browsers are you seeing the problem on?

Firefox

Logs

Additional Notes

No response

[advplyr]

This will be patched shortly