RSS Feed Add doesn't work behind a reverse proxy

[techied]

Please provide the following information

qBittorrent version and Operating System

qbittorrent-nox

4.3.0~202008132103-7037-e1d097a92~ubuntu18.04.1

On Ubuntu Server 18.04.1

If on linux, libtorrent-rasterbar and Qt version

libtorrent-rasterbar

1.2.6+git20200425.a9968916ca-1ppa1~18.04

no qt (nox, headless, no gui)

What is the problem

While qBittorrent 4.2.5 works great behind a nginx reverse proxy (which I believe is somewhat of a common occurrence), the functionality to add an RSS feed and to add an RSS feed download rule is broken because it accesses APIs located at the root of qBittorrent's web server, which are not at the root of the nginx proxy

What is the expected behavior

The webUI uses relative paths in a way that allows these APIs to work behind a nginx reverse proxy

Steps to reproduce

1. Run qBittorrent behind a nginx proxy, with qBittorrent located at a path other than the server root
2. Open your browser devtools
3. Access qBittorrent and try to add an RSS feed subscription or download rule
4. Notice the 404 from nginx in your devtools
5. Right click and copy the request as a cURL
6. Paste said cURL into your terminal, but rewrite the URL, placing your qBittorrent path in, and run the cURL command
7. refresh qBittorrent and observe the RSS feed subscription is added successfully

Extra info(if any)

[seproDev]

@FranciscoPombal feel free to ping me on RSS WebUI related issues

[techied]

Thanks for the fast fix @SeproDE