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Mobylette 2.0+ deprecated the respond_to_mobile_requests method.
Now you must use `include Mobylette::RespondToMobileRequests` instead.
to configure it, see the configuration.
Also stylesheet and javascript helpers were removed.

Mobylette 1.6+ only supports Ruby 1.9.2+
For Ruby 1.8.7 support, please use version < 1.6


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This gem works by adding the ‘mobile’ format to your rails application. Whenever a request come from a mobile device, if you have your controller mobile enabled, it shall render the instead of the view.html.erb (or haml, or whatever).

How does it work?

By adding “respond_to_mobile_requests” in your application_controller (or any other controller), your controllers (or that controller) will understand mobile requests as a new mime type alias “mobile”. This will make the controller to search for the .mobile.erb file instead of the .html.erb. Also you will be able to do:

respond_to do |format|
  format.html   { ... } { ... }


Add the gem to your gemfile:

gem 'mobylette'

And add to your ApplicationController.rb (for enabling it to all your controllers) or to the controllers you want this functionality on:

include Mobylette::RespondToMobileRequests

After that, you may start adding your .mobile. views.


  • is_mobile_request?

    This helper returns true if the request comes from a mobile device, false if it does not.

  • is_mobile_view?

    Returns if the current format is :mobile or not.

  • request_device?

    Returns true/false if the current request comes from the device passed as parameter.



    Only :iphone, :ipad, :ios and :android are recognized by default. But you can add other devices, check configuration.


You can set the configuration with the mobylette_config method:

mobylette_config do |config|
  ... configuration

Custom User Agents

Mobylette works upon detecting the user agent of the visitor browser. By default it will detect any mobile user agent. But you can customize this by passing a proc with a regex of any matching user agent you may wish.

mobylette_config do |config|
  config[:mobile_user_agents] = proc { %r{iphone|ipad}i }

Skipping User Agents

If you need to exclude one or more user agents from the mobile format, lets say ipad for example, you may use the :skip_user_agents option:

mobylette_config do |config|
  config[:skip_user_agents] = [:ipad]

Fall Backs

Fall backs are handled as a chain of formats. By default the only chain is ‘:mobile => [:mobile, :html]`. You can override this and add your own fall back chains using the `mobylette_config`.

mobylette_config do |config|
  config[:fallback_chains] = {
    mobile: [:mobile, :html],
    iphone: [:iphone, :mobile, :html],

When you create a custom format with fall back chains, ‘:iphone` for example, you must register it as a Mime::Type:

# config/initializers/mime_types.rb
Mime::Type.register_alias 'text/html', :iphone
# this is very important, don't forget!
# :mobile is already registered!

If you don’t want any fall backs, just set it to:

mobylette_config do |config|
  config[:fallback_chains] = { mobile: [:mobile] }

XHR Requests

By default the mobile device verification will skip XHR requests, and these will be served as if mobylette wasn’t there. You can override this behavior by setting the :skip_xhr_requests option to false on your controller:

mobylette_config do |config|
  config[:skip_xhr_requests] = false

You may need to use this if you are using JQuery mobile or something similar in your application.

Registering Mobile Devices

Mobylette 3.0+ has a ‘request_device?` helper. By default only :iphone, :ipad, :ios and :android devices come registered. But you can register any device using the `mobylette_config` method:

mobylette_config do |config|
  config[:devices] = { my_unique_phone: %r{UniquePhone 1.2.3}, ... }

Note: This will not add the device to the mobile user_agent detection. For that read #Custom User Agents.

Skipping mobile filter

In the case you need to skip a mobile_request for been treated as mobile, you can pass the ‘skip_mobile=true` param to the url/request.

For example, you are using jquery_mobile and by that ‘:skip_xhr_requests = false`, but there is a special case where you need to process an Ajax, then you can use this param.

Forcing/Ignoring Mobile Requests

You may force your user to aways render the mobile format, or to aways render the default request format (when the request comes from a mobile device). You can use the session var :mobylette_override for doing it:

session[:mobylette_override] = :ignore_mobile

This will skip the code that would force the mobile format. By doing this, your user will aways render the ‘original’ version of your app.

session[:mobylette_override] = :force_mobile

This will force the mobile format rendering, no matter from where the user is requesting it (unless it’s a xhr request).

session[:mobylette_override] = nil


Be sure you are forcing / skiping mobile requests e.g. in a before_filter like : skip_or_force_mobile BEFORE you are including the Mobylette::RespondToMobileRequests module. Mobylette adds own before_filter to check the session var which would be executed before your filter.

class ApplicationController < ActionController::Base 

  before_filter :skip_or_force_mobile

  include Mobylette::RespondToMobileRequests

  mobylette_config do |config|
    config[:mobile_user_agents] = proc { %r{iphone|android}i }
    config[:skip_user_agents]   = []

  # ...

  def skip_or_force_mobile
    session[:mobylette_override] = :ignore_mobile if params[:skip_mobile]
    session[:mobylette_override] = :force_mobile if params[:force_mobile]

This will disable any override (default).

If you need to customize how mobile requests are identified you can override the ‘is_mobile_request?` method in your controller, with your own logic. For example, if you want the to render mobile views, and the to render the normal views:

class ApplicationController << ActionController::Base
  include Mobylette::RespondToMobileRequests



  def is_mobile_request? == ""


Don’t drive your mobylette without your Helmet! It’s safer to do tests!

For testing, include the Mobylette::Helmet module to your test/test_helpers.rb:

require 'mobylette/helmet'
include Mobylette::Helmet

For RSpec: add to your spec/spec_helpers.rb or create a spec/support/mobylette.rb with the following:

require 'mobylette/helmet'
RSpec.configure do |config|
  config.include Mobylette::Helmet, :type => :controller

This will add 3 methods to your test scope:

force_mobile_request_agent(agent = 'Android')

This will force a mobile user_agent, allowing you to test mobile requests.


This will reset your user_agent to the test default “Rails Testing”. You don’t need to call this every time, all your requests by default are “Rails Testing” in your test env.


This will force the session_override value in the users session. Values possible values are: :ignore_mobile and :force_mobile

Friendly note: on your tests, call these functions BEFORE you make the request, otherwise they are useless =p


MIT License. Copyright 2012 Tiago Scolari.