Bug: Setting ROOT_URL causes 404 not found

[admlko]

TLDR: Setting ROOT_URL environment variable doesn't seem to work correctly, WebUI won't load

1. Is this urgent: No

2. DNS provider(s) you use: Gandi

3. Program version: Docker latest tag

   Running version latest built on 2024-05-23T13:33:03.304Z (commit 8e09cd6)

4. What are you using to run the container: UnRAID Docker

5. Extra information:
   Working: ROOT_URL: /
   Not working: ROOT_URL: /ddns

Logs:

2024-06-01T07:52:57+03:00 INFO Settings summary:
├── HTTP client
|   └── Timeout: 10s
├── Update
|   ├── Period: 5m0s
|   └── Cooldown: 5m0s
├── Public IP fetching
|   ├── HTTP enabled: yes
|   ├── HTTP IP providers
|   |   └── all
|   ├── HTTP IPv4 providers
|   |   └── all
|   ├── HTTP IPv6 providers
|   |   └── all
|   ├── DNS enabled: yes
|   ├── DNS timeout: 3s
|   └── DNS over TLS providers
|       └── all
├── Resolver: use Go default resolver
├── Server
|   ├── Listening address: :8000
|   └── Root URL: /ddns
├── Health
|   └── Server listening address: 127.0.0.1:9999
├── Paths
|   └── Data directory: /updater/data
├── Backup: disabled
└── Logger
    ├── Level: info
    └── Caller: hidden
2024-06-01T07:52:57+03:00 INFO reading JSON config from file /updater/data/config.json
2024-06-01T07:52:57+03:00 INFO Found single setting to update record
2024-06-01T07:52:57+03:00 INFO Reading history from database: domain xxx.tld host yyy ipv4
2024-06-01T07:52:57+03:00 INFO [backup] disabled
2024-06-01T07:52:57+03:00 INFO [healthcheck server] listening on 127.0.0.1:9999
2024-06-01T07:52:57+03:00 INFO [http server] listening on :8000
2024/06/01 07:53:01 "GET http://SERVERIP:2245/ddns HTTP/1.1" from CLIENTIP:58761 - 404 19B in 7.688µs
2024/06/01 07:53:01 "GET http://SERVERIP:2245/favicon.ico HTTP/1.1" from CLIENTIP:58761 - 404 19B in 6.427µs

Configuration file (remove your credentials!):

{
  "settings": [
    {
      "provider": "gandi",
      "domain": "xxx.tld",
      "host": "yyy ",
      "personal_access_token": "MYSUPERSECRETTOKEN",
      "ttl": 3600,
      "ip_version": "ipv4",
      "ipv6_suffix": ""
    }
  ]
}

Host OS: UnRAID latest

[qdm12]

You need a / suffix to the address: http://SERVERIP:2245/ddns/
I pushed a change 76afd83 to serve the root now on both /rooturl and /rooturl/ if rooturl is not empty.