Issue Description: When Dynmap's internal webserver is reverse-proxied to a subdirectory of a domain, it expects its files (config.js, css/, up.php, etc.) to be at the root of the domain, rather than the subdirectory of the domain.

• Dynmap Version: Dynmap-3.4-SNAPSHOT-spigot
• Server Version: Paper 1.19, build 17
• Pastebin of Configuration.txt: https://pastebin.com/XyRERTux
• Server Host (if applicable): self-hosted (Debian sid, uname = 5.18.0-1-amd64 #1 SMP PREEMPT_DYNAMIC Debian 5.18.2-1 (2022-06-06) x86_64 GNU/Linux
• Pastebin of crashlogs or other relevant logs: N/A, screenshot of JS console @ https://play.example.com/map/index.html
• Other Relevant Data/Screenshots:
  • Relevant apache2 configuration (note that the play. subdomain isn't necessary here)
  • Dynmap shows a blank white screen with title "Minecraft Dynamic Map" @ example.com/map
  • Dynmap shows a blank black screen with title "Minecraft Dynamic Map" @ example.com/map/index.html
    • While messing with apache2 configurations, I got this URL work once, but I can't recall how...
• Steps to Replicate:
  1. Start a Spigot-based Minecraft server
  2. Install the Dynmap plugin
  3. Set up a webserver that reverse-proxies Dynmap's internal webserver to a subdomain
     • i.e http://localhost:8123/ to https://example.com/map
     • I imagine this issue isn't strictly limited to apache2; it should exist on nginx and other webservers

Basically, this works (apache2):

ProxyPass / http://localhost:8123

But this does not:

ProxyPass /map http://localhost:8123

I imagine this can be solved by using Dynmap's external webserver configuration, but that seems unnecessarily complicated - I would have to re-copy Dynmap's ./plugins/dynmap/web directory every time I update Dynmap, no?

Another solution would be to manually reverse-proxy each and every file and directory Dynmap looks for, as seen here, but that's terribly ineloquent.

[x] I have looked at all other issues and this is not a duplicate
[x] I have been able to replicate this

This also occured to me until i do /map/ instead of /map on my nginx config file
I know this might be dumb, but you can try do the same

EDIT: attached my nginx config screenshot

@Velosofy That worked! Though I'm not sure why. (Note that, while example.com/map still does not work, example.com/map/ - note the trailing slash - and example.com/map/index.html do work.)

Here's the relevant bit of my apache2 configuration:

Redirect "/map" "/map/index.html"

<Location /map/>
    Options Indexes FollowSymLinks
    AllowOverride None
    Require all granted

    ProxyPass http://localhost:8123/
    ProxyPassReverse http://localhost:8123/
</Location>

(Using mod_rewrite to go from ^map$ to map/index.html didn't work, for some reason...)

Should I keep this issue open? This solution is good enough, but I feel that it should still be possible to access Dynmap from e.g. example.com/map (no trailing slash).

I'm sorry but doesn't it redirect example.com/map in your browser to example.com/map/ anyway?
At least that's my case. That's why I don't bother to open a issue or try a different approach

@Velosofy Not by default, hence the need for Redirect "/map" "/map/index.html". Otherwise I get a 404 @ example.com/map.

Oh, perhaps that only apply with nginx. I can't help you further to fill your needs

or this instead:

Redirect "/map" "/map/"

<Location /map/>
    Options Indexes FollowSymLinks
    AllowOverride None
    Require all granted

    ProxyPass http://localhost:8123/
    ProxyPassReverse http://localhost:8123/
</Location>

@brunoherrera Yes, Redirect "/map" "/map/index.html" and Redirect "/map" "/map/" are practically identical in this case.

Now looking back at this
/map doesn't really count as a subdir, does it?

@Velosofy If we consider / to be the root directory of a website, then /map would be a subdir thereof.
https://example.com/
vs.
https://example.com/map