Sometimes you type a hash-bang URL too fast, bang first.

Consider https://artsy.net/!#/log_in. Rails will receive /! as the file path, resulting in a 404, File Not Found error. The part of the URL after the hash is a position within the page and is never sent to the web server.

It’s actually pretty easy to handle this scenario and redirect to the corresponding hash-bang URL.

The most straightforward way is to create a file called !.html in your public folder and use JavaScript to rewrite the URL with the bang-hash.

``` html public/!.html

You can also do this inside a controller with a view or layout. Start by trapping the URL in your `ApplicationController`.

``` ruby app/controllers/application_controller.rb
if request.env['PATH_INFO'] == '/!'
  render layout: "bang_hash"
  return
end

The layout can have the piece of JavaScript that redirects to the corresponding hash-bang URL.

``` ruby app/views/layouts/bang_hash.html.haml !!!

• ie_tag(:html) do %body :javascript window.location = ‘/#!’ + window.location.hash.substring(1) ```