for faster access I store in the www directory of my app HTML files generated by the app. I embed them via an iframe, e.g.
<iframe src="https://myserver/myapp/mygeneratedfile.html" />. The problem appears when the file is not yet generated. The Iframe simply contains an
<h1>Page not found</h1>, but of course I would like to link to my app then.
I tried to make a custom error-404.html with a template directive in the shiny server configuration. But the custom error 404 page does not appear and from the documentation I have the impression it is not possible. So it is really impossible?