🐛 Bug Report: Can not use behind reverse proxy with path different root

[resetsa]

I use v0.35.1 version as docker container.
And cannot use behind reverse proxy (NGINX), because many request used wrong URI.

My nginx config

   ...
    location /redlib/ {
        proxy_pass http://redlib:8080/;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_http_version 1.1;
    }
    ...

If I use this - all fine.

    location / {
        proxy_pass http://redlib:8080/;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_http_version 1.1;
    }

I want to use not root URI for proxying to redlib service.

Typical log from NGINX

2025/01/30 06:20:28 [error] 20#20: *19 open() "/var/www/thumb/b/H7a8FF_jgDIPQSCjUbKi1LouxlT1cWW3xDHkS8-Cvyo.jpg" failed (2: No such file or directory), client: xx.xx.xx.xx, server: xxx.xxx.xxx, request: "GET /thumb/b/H7a8FF_jgDIPQSCjUbKi1LouxlT1cWW3xDHkS8-Cvyo.jpg HTTP/1.1", host: "xxx.xxx.xxx" xx.xx.xx.xx - - [30/Jan/2025:06:20:28 +0000] "GET /thumb/b/H7a8FF_jgDIPQSCjUbKi1LouxlT1cWW3xDHkS8-Cvyo.jpg HTTP/1.1" 404 548 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 OPR/116.0.0.0" "-"

Screen with problem

I tried to use FULL_URL but it not helped.

[ButteredCats]

Redlib doesn't have any sort of option to support running under a subdirectory. The FULL_URL option is related to RSS feeds.

I'm not sure if you're aware of the reason running under a subdirectory breaks Redlib (and lots of other apps) but in case you aren't I'll try and explain it:
Within the HTML of the page any link to another resource, stuff like CSS, javascript, or images, starts with /. Take /style.css for example, this causes clients to request /style.css rather than /redlib/style.css and because /style.css is not within your /redlib/ block, NGINX attempts to serve the clients a local file which doesn't exist rather than using your proxy_pass to Redlib and that's why you see those open() errors in the log.

However, it may be possible to get this to work by using a rewrite https://nginx.org/en/docs/http/ngx_http_rewrite_module.html#rewrite

If possible I'd suggest using a subdomain instead of using a subdirectory, it's a lot easier. Even if you can start redirecting requests for / to /redlib/ I'm not sure how you'd extend that to be compatible with more things running under other subdirectories.