(feat) allow deployment under relative base path

[behackl]

Pull Request Checklist

• Description: Briefly describe the changes in this pull request.
• Changelog: Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description.
• Documentation: Have you updated relevant documentation?
• Dependencies: Are there any new dependencies? Have you updated the dependency versions in the documentation?

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Description

This introduces some changes mainly to the frontend (plus the construction of manifest.json in the backend) that allows setting a relative base path via the environment variable (or, in the context of the docker build process, the build argument) WEBUI_BASE_PATH.

Please note: I am not familiar with svelte at all, and it feels like there might be a much simpler solution than what I did here -- however, I've used this branch to deploy a working instance behind a standard reverse proxy configuration (in this case Apache):

ProxyPreserveHost On
ProxyPass /chat http://example.com:8077
ProxyPassReverse /chat http://example.com:8077

such that the interface is available at https://original.example.com/chat.

Related to #1162.

Unfortunately I won't have time to put much more effort towards this, maybe this can be useful to whoever comes up with a proper implementation of this feature eventually. :-)

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Changelog Entry

Added

• Docker build argument WEBUI_BASE_PATH which controls the relative base path used in the built frontend (plus in manifest.json).

[krosk]

Nice work !

I had a try, it seems in the current implementation, WEBUI_BASE_PATH can be changed at docker build time only, not at deployment time. Is it correct?

[behackl]

Thanks!

WEBUI_BASE_PATH can be changed at docker build time only, not at deployment time. Is it correct?

Indeed, this solution only works when building the docker image.

A version that works during deployment time too would require restructuring the docker build process a bit; currently node is only available in the first build stage (and not in the final container). The frontend would need to be rebuilt whenever the container starts up.

[tjbck]

Closing due to conflicts. Unless there's a more elegant solution to this, we should just add docs on how to host our webui with a relative base path using other reverse proxy tools like nginx. I'm not a huge fan of this current solution for adding relative base path support natively. I appreciate the effort you put in regardless 🙌

[behackl]

I guess it would still be necessary to change the frontend-generated URLs from absolute to relative ones. Except if you were thinking of some sort of automatic URL rewriting by the reverse proxy; I've found these sort of solutions to be somewhat unreliable though.

In any case, I'm sure someone will be able to come up with a clean solution. :-)