Using Cucumber/Capybara in Rails 3, how do I set a custom User-Agent string?

Question

In my Rails 3 app, I have different layouts for iPhone vs desktop browsers. I'm trying to test the iPhone layout using Cucumber/Capybara. So far, all my attempts at setting an iPhone User-Agent string in the request's HTTP header have failed.

I have followed the Testing custom headers and ssl with Cucumber and Capybara tutorial but it doesn't seem to set the User-Agent string in the HTTP request.

If I just browse to my Rails app using my iPhone, I get the right layout. I am using Rack-Mobile-Detect to set the Rails request.format to :iphone.

Any ideas on how to make this work? I'm about ready to ditch Capybara and go back to Webrat.

Here's what I have so far:

Feature: Detect Browser
  In order to have different layouts for iPhone vs. desktop browsers
  As a developer
  I want to show different layouts for different browsers

Scenario: Show home page with desktop layout 
  Given I am using "a desktop browser"
  When I go to "the home page"
  Then I should see "desktop browser"

Scenario: Show home page with iPhone layout
  Given I am using "mobile safari"
  When I go to "the home page"
  Then show me the page
  Then I should see "mobile safari"

Detect_browser_steps.rb

Given /^(?:|I )am using (.+)$/ do |browser|
  case browser
  when "mobile safari"
    agent = "Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11 Safari/528.16"
    add_headers({'User-Agent' => agent})
  else
    # don't set a special User-Agent header
  end
end

headers_hack.rb

# http://aflatter.de/2010/06/testing-headers-and-ssl-with-cucumber-and-capybara/
# The following solution will work only if you use the :rack_test driver.
module RackTestMixin

  def self.included(mod)
    mod.class_eval do
      # This is where we save additional entries.
      def hacked_env
        @hacked_env ||= {}
      end

      # Alias the original method for further use.
      alias_method  :original_env, :env

      # Override the method to merge additional headers.
      # Plus this implicitly makes it public.
      def env
        original_env.merge(hacked_env)
      end
    end
  end

end

Capybara::Driver::RackTest.send :include, RackTestMixin

module HeadersHackHelper

  def add_headers(headers)
    page.driver.hacked_env.merge!(headers)
  end

end

World(HeadersHackHelper)

Answer 1

Hey there. Glad you found my post ;-)

Did you check if Rack::Test passes your header to the controller? You could try something like Rails.logger.info("Headers: #{headers.inspect}")in your controller and then inspect your log file.