How To: Make Devise Work With Other Formats Like Mobile, IPhone And IPad (Rails Specific)

Make your app render Apple iOS templates for iOS devices like iPhone, iPad, iPod Touch, etc.

Add the following to app/controllers/application_controller.rb:

# app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  before_filter :adjust_format_for_iphone

  private

  def adjust_format_for_iphone    
    request.format = :ios if request.env["HTTP_USER_AGENT"] =~ %r{Mobile/.+Safari}
  end
end

Set Devise to display views for iOS.

Add every desired format to config.navigational_formats in config/initializers/devise.rb.

# config/initializers/devise.rb

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

Create each view you need for Devise (login form, signup form, etc.).

Name your view something like new.**ios**.erb, e.g. app/views/devise/sessions/new.ios.erb for login form.

Create an initializer in config/initializers (e.g. config/initializers/mobile_formats.rb) with the following:

# config/initializers/mobile_formats.rb

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

Add your format to config/initializers/mime_types.rb

# config/initializers/mime_types.rb

Mime::Type.register_alias "text/html", :ios

Note that if you use OAUTH for Facebook you will need to configure it to use facebook's mobile authentication path. This post explains how.