How to implement themes for a multidomain application?

[kberov]

I have an application which serves several domains.

Each incoming request may be for a different than the previous domain.
I would like to have different themes for the different domains - same templates names - just in different renderer paths.

So far I implemented in around_dispatch to switch the template paths,

sub _around_dispatch ($next, $c) {
# ...
  state $s_paths = $app->static->paths;
  state $r_paths = $app->renderer->paths;
#...complex logic here
  unshift @{$s_paths}, "$root/$dom->{domain}/public";
  unshift @{$r_paths}, "$root/$dom->{domain}/templates";
  $next->();
  shift @{$s_paths};
  shift @{$r_paths};
}

But templates from different paths have the same names and Mojolicious::Renderer does not differentiate the cached templates by name.
On the next request(different domain from the previous one) in morbo I see:

[2020-12-18 23:23:20.34523] [9675] [debug] [8M98jmSZ] Rendering cached template "foo/bar.html.ep"
[2020-12-18 23:23:20.34569] [9675] [debug] [8M98jmSZ] Rendering cached template "partials/bazz.html.ep"
# etc...

How to set the template name so for Mojolicious::Renderer the templates
/here/foo/bar.html.ep and /there/foo/bar.html.ep are different.
Please note that /here and /there are my template roots - different on each request.

[kberov]

This works for now, but only in CGI mode when the templates are not cached.

[Grinnz]

You can disable the template cache if you wish, see https://stackoverflow.com/a/41751645/5848200. This of course can be a significant performance impact as every request will have to read templates from disk.

Perhaps it would be a more efficient (and cacheable) setup to have the domains as subdirectories within the template path, prepended at the time of selecting the template.

[Grinnz]

Another more common idea is just to run multiple instances of the app - using Toadfarm or your reverse proxy to dispatch to the correct app based on domain, and having the template/static dirs read from config for each instance.

[kberov]

@Grinnz, currently the application is on a cheap shared hosting, running as CGI (no caching of templates) and there is no problem, but if the time come when I have to move to a stand-alone app served by hypnotoad, I would prefer to be able to do it without changing the file/folders layout.

[Grinnz]

The caching mechanism is a Mojo::Cache object accessible via $app->renderer->cache, and thus can be replaced or customized as https://metacpan.org/pod/Mojolicious::Plugin::Renderer::WithoutCache does for example.

[mche]

cache key

Cache key would be full path to disk file instead the file name. So your put project folders [email protected], [email protected] ... and [email protected], [email protected] ...

And then around_dispatch

[kberov]

Thanks @mche. I have different domain folders. Not sure how to implement your proposal(предложение).
I implemented $cache->key_prefix($dom->{domain}); and used it in around_dispatch, so later (during the same request) when the renderer caches the template, found in the respective domain specific folder, it caches it with the specific domain key prefix. In my application the prefix and the renderer, and static paths are switched on each request, depending on the current domain. On the next request the renderer will find the cached template using the respective domain's prefix.

This is action at a distance. Otherwise I had to implement my own renderer, because I did not find another way to tell EPLRenderer what the name of the template is.

May be I can get rid of my Slovo::Cache if I do not need cache_prefix, but did not figured out how to do it.
And here is my current implementation of around_dispatch.
Can you give a concrete idea with example? Thanks again.

[mche]

@kberov, I had own patched cache key from name to path at Mojolicious::Plugin::EPRenderer

my $name = $options->{inline} // $renderer->template_path($options) || $renderer->template_name($options);

I dont know why that is impossible global patch for team.