[janosmurai]

Type of change

• New feature
• Bug fix
• Breaking change
• Refactoring or maintenance
• Documentation update

Related issue

Closes SHD-1087

Description

With WEBAPP_URL set, /app/ returned the server's own route_not_found 404, while /app, /app/index.html and the assets were proxied correctly. The web app is built with base path /app/, so /app/ is its canonical URL.

ReverseProxy mounts itself with Router::nest(path, ...). In axum 0.8, nest matches path and path/{*rest}, and a catch-all never matches an empty remainder, so path/ fell through to fallback_404. /control-panel/ had the same gap.

The new routes::proxy::subpath_proxy mounts the proxy as before and also routes path/ to it with route_service. Both /app and /control-panel now use it. The proxy strips its own base path, so /app/ reaches the upstream as /, the same as /app.

Validation

• cargo fmt --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo build --verbose --all-features
• cargo test --verbose --all-features

Additional validation details:

• Ran just check, which covers the four checks above.
• New tests in routes/proxy.rs run the router against a real upstream server that echoes the path it received. /app, /app/, /app/index.html and /app/assets/index.js?v=1 should reach the upstream as /, /, /index.html and /assets/index.js?v=1. /, /application and /v1/models should not be proxied.
• With the new /app/ route removed, the test fails at /app/ with (404, ""), which reproduces the bug.

Deployment and compatibility

None. No configuration or API changes. /app/ and /control-panel/ now reach their upstream instead of returning 404.

Documentation

None needed. This makes the documented /app proxy behave as expected.

Checklist

• I added or updated tests for changed behavior, or explained why tests are not needed.
• I updated user-facing and API documentation where necessary.
• My commits follow the Conventional Commits specification.
• Every commit includes a Signed-off-by trailer (git commit -s).

AI assistance:

• Tool: Claude Code
• Model: Claude Opus 5.5
• Used for: root-cause analysis in axum-reverse-proxy, the fix, the tests and this description
• Human verification: done