[haertig]

Why not simply this:

server {
        listen 80;       
        location /calibre {
                proxy_buffering off;
                proxy_set_header X-Forwarded-For $remote_addr;
                proxy_pass http://10.192.0.2:8080$request_uri;
        }
}

Rather than what the Calibre documentation recommends:

server {
        listen 80;
        proxy_set_header X-Forwarded-For $remote_addr;
        location /calibre/ {
                proxy_buffering off;
                proxy_pass http://10.192.0.2:8080$request_uri;
        }
        location /calibre {
                rewrite /calibre /calibre/ permanent;
        }
}

I have tested both configs, and cannot see any difference in how they function from the web browser client end-user viewpoint. Things seem to work just fine either way. Is there some special case that I am not testing that requires the second, longer specification?

I have tested with these URLs:

http://10.192.0.26/calibre
http://10.192.0.26/calibre/
http://10.192.0.26/calibre/#library_id=Calibre&panel=book_list&sort=author_sort.asc,series.asc&vl=Novels

[ Note: Calibre Content Server started like this: calibre-server --url-prefix /calibre --num-per-page=999 --port 8080 ]

[ Note: 10.192.0.26:80 runs the NGINX reverse proxy (Raspberry Pi3/Raspbian), 10.192.0.2:8080 runs the caliber-server (LinuxMint18 Sarah) ]