Implementing Wordpress-like dynamic theme selection within Elixir/Phoenix?

Hi.

I think you could just replace the static :root in :put_root_layout with a function, which fetches the layout dynamically, e.g:

plug :put_root_layout, {CmsWeb.LayoutView, CmsWeb.current_theme()}

and then you need to define a matching render function handling the evaluation of the templete (for production you would probably just compile it once and call Code.eval_quoted in the render function):

defmodule CmsWeb.LayoutView do
  use CmsWeb, :view

  def render(theme_name, assigns) do
    theme_name
    |> CmsWeb.path_for_theme()
    |> EEx.eval_file([assigns: assigns], engine: Phoenix.HTML.Engine)
  end
end

When installing a new template, you then would need to download the theme file to some location and add a database entry containing the name and the path to the template file.

Not sure if that is the nicest way, but it should work.