[Feature] Support X-Forwarded-Prefix

[n3fariox]

I'm using Traefik as a reverse proxy to expose it publicly and was wanting to put RomM at a different base path.

Traefik has a StripPrefix middleware which strips the prefix and puts it in the X-Forwarded-Prefix header.
It would be nice if RomM would recognize this and use this in the Vue router.
Maybe a BASE_PATH_HEADER env var that specifies the header to get the base path from?

I know I can use the BASE_PATH environment variable, but that would require local users to also use the same path and the proxy config is where I'm setting the prefix.

• Traefik Middleware
  • https://doc.traefik.io/traefik/reference/routing-configuration/http/middlewares/stripprefix/

[gantoine]

I know I can use the BASE_PATH environment variable

In romm or traefik? IIRC romm doesn't have a BASE_PATH env var, we only support subdomain setups.

[n3fariox]

It seems to be configurable in the router? (BASE_URL, my bad)

• romm/frontend/src/plugins/router.ts

  Line 293 in d76cd34

  history: createWebHistory(process.env.BASE_URL),

And this guy in the backend:

• romm/backend/config/__init__.py

  Line 24 in d76cd34

  ROMM_BASE_URL: Final[str] = _get_env("ROMM_BASE_URL", "http://0.0.0.0")

Though I haven't tried to see if that actually works.

[gantoine]

ya we don't set the BASE_URL used in the frontend, so at the moment there's no way to use a /romm path for the app.

[n3fariox]

Staring at this a bit more, I realized the BASE_URL is currently a BUILD time setting, so you'd need to custom build the app with the path set (not dynamic like I'd want).

So to add this, the pain points would be:

• Vue apps can't access request headers
• Would need python (or something) to inspect the headers and render index.html with some inject some js to pass in the prefix
• Nginx config is updated to point at the python server for index

Tougher here since the static files are not already served by the fastapi app.

Similar to the following issues, but I just need the client side to generate correct links relative to the base and not actually host things on a different URL:

• [Feature] Base URL config option #379
• [Feature] Allow setting the base uri for the server #1604