Live error 404 without changind URL bar?

Questions & Help Questions
1

I have a route at the end to match all routes and manually call a controller for rendering (with layout) a 404 html.heex in live mode:

match :*, "/*path", MyProject.Error404Controller, :call

With the modules:

defmodule MyProject.Error404Controller do
   use MyProject, :controller

   import Phoenix.LiveView.Controller

   def call(conn, _) do
      conn
      |> put_status(:not_found)
      |> live_render(MyProject.Error404Live, session: %{"path" => conn.request_path})
   end
end

defmodule MyProject.Error404Live do
   use MyProject, :live_view

   def render(assigns) do
      Phoenix.View.render(MyProject.ErrorView, "404.html", assigns)
   end

   def mount(_params, %{"path" => path}, socket) do
      {:ok, assign(socket, :path, path)}
   end

   # I also need handle_params which triggers the error
end

Problem is that I need handle_params function to initialize some internal stuff, but since the liveview was not started via live/3 macro, I am getting:

cannot invoke handle_params/3 on MyProject.Error404Live because it is not mounted nor accessed through the router live/3 macro

As I understand it, this seems a phoenix current limitation which according to Jose Valim this limitation might be removed in the future.

I’ve seen similar posts regarding this and there are suggestions that I enable a new route like /404/*path called using live/3 macro and just let the error redirect. While this might work, it will change URL bar which will confuse the user.

Is there any way to accomplish a full 404 error page with layouts enabled and in full liveview mode? (This is because inside the layout I am using @socket instead of @conn.

Thanks.