iOS/mobile detection with devise

So I'm using User Agent detection to serve different views within my app by serving example.mobile.haml rather than example.html.haml. It's all working fine apart from some funny things happening with devise views.

When I hit the root as a desktop UA (Safari, Mac OS) it correctly redirects to /login with a flash, when I do this as a mobile UA it doesn't redirect and displays only the flash and renders no additional HTML.

Similarly, hitting /logout as a desktop UA correctly logs out and redirects to /login as it should. But doing this as a mobile UA hits /logout, destroys your session but doesn't redirect.

I've followed all the instructions on the devise wiki but this is al开发者_如何学JAVAl that won't work. The code that does all of the detection is below:

#application_controller.rb

def format_for_mobile
  request.format = :mobile if mobile_user_agent?
end

def mobile_user_agent?
    request.env["HTTP_USER_AGENT"]
    request.env["HTTP_USER_AGENT"][MOBILE_USER_AGENTS]
end


# config/initializers/devise.rb

config.navigational_formats = [:"*/*", "*/*", :html, :to_mobile]


# config/initializers/mobile_responder.rb

ActionController::Responder.class_eval do
  alias :to_mobile :to_html
end

Managed to figure this out myself. The before_filter :format_for_mobile was before authenticate user, that fixed the /login issue.

For /logout, I had to do the following:

# controllers/sessions_controller.rb

class SessionsController < Devise::SessionsController
  before_filter :format_for_mobile, :except => :destroy
end