Improved theming to fully replace legacy themes

[juliusknorr]

The old custom theme mechanism was deprecated quite a while ago in favor of the theming app but we still keep it around since there are a couple of common cases that are not yet covered by the theming app approach:

• Replace templates (while this is quite common, I'm unsure if we want to continue supporting it)
• Replace icon files (Theming app: allow Talk icon to theme #27423)
• Replace translations

My initial idea would be that we could handle this in addition to #15815 and allow any app to register for handling theming. That way if a custom theme is required with additional customization such as changing image/template paths or translations we could add hooks to let a separate app handle those then.

cc @nextcloud/server-triage What do you think about that, especially if we should continue supporting those individual possibilities?

[skjnldsv]

I think it's about time we drop the support of it yes.
Some might still use it though, especially companies I think, we have to check 🤔

[juliusknorr]

Some might still use it though, especially companies I think, we have to check thinking

Yeah it is unfortunately quite heavily asked and used feature to change those parts. Especially overwriting the header template or login is actively used.

[gymnae]

Please don't remove this feature without offering a replacement. The theming app does not allow for multi-domain theming, while one can achieve this via custom themes.

[skjnldsv]

multi-domain theming

what is this? And what is the use case for it?

[gymnae]

multi-domain theming

what is this? And what is the use case for it?

If you have one install and differnt domains pointing to it. For example one for the family, one for your hobby friends and one for you personally. Instead of spinning up extra installs, one would be enough, just with customized theming. Just like was possible with the legacy themes, of which the "example" is still shipped with nextcloud, although half-defunct (meta tags don't stick, primary color setting is ignored)

[skjnldsv]

So you're providing different themes based on the hostname?

[gymnae]

Yes, I described my current approach here: https://help.nextcloud.com/t/howto-individual-themes-per-domain/27585/24

[skjnldsv]

Sorry, but this is such an edge case, I don't think we will keep legacy theming for this :/