HTTP upload broken when public PUT URL path differs from request_handler definition

Environment

• ejabberd version: 23.01
• Erlang version: Erlang (SMP,ASYNC_THREADS) (BEAM) emulator version 13.1.5
• OS: Linux (Devuan)
• Installed from: distro package

Configuration (only if needed): grep -Ev '^$|^\s*#' ejabberd.yml

listen:
  -
    port: 5280
    ip: "::1"
    transport: tcp
    module: ejabberd_http
    request_handlers:
      /upload: mod_http_upload
      /.well-known/host-meta: mod_host_meta
      /.well-known/host-meta.json: mod_host_meta
modules:
  mod_http_upload:
    hosts:
      - upload.@HOST@
    access: local
    get_url: "https://upload.@HOST@/"
    put_url: "https://upload.@HOST@/"
    docroot: "@HOME@/upload"
    dir_mode: "0750"
    file_mode: "0644"
    rm_on_unregister: true
    jid_in_url: sha1
    thumbnail: false
    custom_headers:
      "Access-Control-Allow-Origin": "https://upload.@HOST@/"
      "Access-Control-Allow-Methods": "GET,HEAD,PUT,OPTIONS"
      "Access-Control-Allow-Headers": "Content-Type"

Errors from error.log/crash.log

2023-07-05 18:09:22.480526+02:00 [info] <0.390.0>@ejabberd_listener:accept/7:273 (<0.576.0>) Accepted connection hidden_by_ejabberd -> [::1]:5280
2023-07-05 18:09:22.481919+02:00 [debug] <0.576.0>@ejabberd_http:init/3:129 S: [{[<<"upload">>],mod_http_upload},
    {[<<".well-known">>,<<"host-meta">>],mod_host_meta},
    {[<<".well-known">>,<<"host-meta.json">>],mod_host_meta}]

2023-07-05 18:09:22.483200+02:00 [debug] <0.576.0>@ejabberd_http:process_header/2:290 (#Port<0.44>) http query: 'PUT' <<"/upload/01a66df340fbde62dc61c6746f33783061170e87/ZR7WpuNlK22WQhj3GVWoTouTBF2btSE9QnxEdl9E/20221221_201620_20221223230532.jpg">>

2023-07-05 18:09:22.484977+02:00 [debug] <0.576.0>@ejabberd_http:process/1:362 [<<"upload">>,<<"01a66df340fbde62dc61c6746f33783061170e87">>,
 <<"ZR7WpuNlK22WQhj3GVWoTouTBF2btSE9QnxEdl9E">>,
 <<"20221221_201620_20221223230532.jpg">>] matches [<<"upload">>]
2023-07-05 18:09:22.486212+02:00 [warning] <0.576.0>@mod_http_upload:process/2:570 Cannot handle PUT request from hidden_by_ejabberd for upload.example.com: Upload not configured for this host

Bug description

To have beautiful HTTP URLs for the HTTP upload file transfer module I have installed a web server in front of ejabberd which takes requests on https://upload.example.com/ and forwards them to ejabberd's local port (http://[::1]:5280/upload/).

ejabberd prints the misleading error message Upload not configured for this host when the path of the request does not match the one configured in mod_http_upload's put_url.

Creating a separate local port whose only request_handler is /: mod_http_upload HTTP uploads work as expected.

Start with the request routing and upload handling shown in ejabberd_http:process/1 and mod_http_upload:process/2, then compare the configured request-handler path with put_url. Reproduce the proxied PUT request and verify that a differing public path no longer produces the misleading “Upload not configured for this host” result; add or update a regression test if the relevant test location is identified.