Inject runtime URLs in the back-end served index.html

[dominiquekleeven]

Closes #65

Currently the front-end bundle contains relative URLs that are embedded during its built process. This bundle is then served by the back-end service.

This change allows the back-end to dynamically inject the configured server URL environment variables into the served index.html which is then used by the front-end as runtime config. This is more flexible and reliable than relying on embedded relative URLs. It only injects the necessary variables and does not expose anything else.

The change also resolves an issue where the WS subscription would fail since the ManagerConfig expects the managerUrl to be absolute (e.g. containing the full address), to determine whether it should use WS or WSS.

this._endpointUrl = (managerUrl.startsWith("https:") ? "wss" : "ws") + "://" + managerUrl.substr(managerUrl.indexOf("://") + 3) + "/websocket/events";

[dominiquekleeven]

Deployed on test4

[MartinaeyNL]

Yeah this PR is fine with me.
I've only got two minor comments to simplify the scope to window, instead of global variables.
I'm not sure whether we should also follow a similar practice for the OpenRemote repository,
but this pattern is perfectly fine within a specific project like this.

[MartinaeyNL]

I assume you removed this fallback to allow ML_OR_URL to be an empty value.
I think if you replace || with ??, it should still work, because it's a better null check.

managerUrl: MR_OR_URL ?? '/'

[dominiquekleeven]

Uses nullish coalesce now, thanks! I keep forgetting it exists haha.