How to fix RailsBaseUri (sub URI) with Phusion Passenger without setting relative_url_root

There is a bug which prevents correct routing with Phusion Passenger 2.2.2 and Rails 2.3.2 (>= 2.2.2) and RailsBaseUri. For example, if you have RailsBaseUri myapp, and you visit http://localhost/myapp/mycontroller/myview, then the request gets routed to controller myapp instead of mycontroller, and you most probably get the error message Routing Error; No route matches "/myapp/mycontroller/myview" with {:method=>:get}. If you visit http://myserver/myapp/mycontroller/myview, you'll get the error message The page you were looking for doesn't exist. You may have mistyped the address or the page may have moved.. This post gives instructions how to work around the bug.

The bug is mentioned in various places, such as
http://blog.ashchan.com/archive/2008/12/10/passengers-railsbaseuri-not-working/ and https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1946-setting-a-relative-root-url-via-a- and http://github.com/rails/rails/commit/a87462afcb6c642e59bfcd2e11e3351e2b718c38 .

The manual workaround (according to what is suggested on the pages above) is adding the line below to config/environments/production.rb:

config.action_controller.relative_url_root = '/myapp'

We propose a completely automatic workaround here, which doesn't need hardcoding URIs to the Rails application configuration. To fix this, create a file config/initializers/!fix_relative_url_root.rb with the following contents:

# automatic relative_url_root fix
# for Phusion Passenger 2.2.2 and Rails 2.3.2 (>= 2.2.2)
# by pts@fazekas.hu at Mon May  4 20:48:38 CEST 2009
# from http://ptspts.blogspot.com/2009/05/how-to-fix-railsbaseuri-sub-uri-with.html
fail unless ActionController::Request       # check loaded
module ActionController
  class Request
    def initialize(env)
      @env = env  # Rack::Request#initialize does only this
      path = request_uri.to_s[/\A[^\?]*/]
      sn = @env['SCRIPT_NAME']
      if (RAILS_ENV == 'production' and
          (sn.empty? or sn.starts_with?('/')) and
          path == sn + @env['PATH_INFO'])
        Base.relative_url_root = sn
      end
    end
  end
end

In addition to the fix above, here is another fix for url_for and redirect_to so they automatically prepend ActionController::Base.relative_url_root when they get a string starting with a slash. To apply the fix, create file config/initializers/!relative_url_for.rb with the following contents:

# fix url_for and redirect_to to use ActionController::Base.relative_url_for
# fix for Rails 2.3.2
# by pts@fazekas.hu at Mon May  4 22:38:44 CEST 2009
# from http://ptspts.blogspot.com/2009/05/how-to-fix-railsbaseuri-sub-uri-with.html
fail unless ActionController::Base          # check loaded
fail unless ActionView::Helpers::UrlHelper  # check loaded
module ActionController
  class Base
    alias url_for__ptsroot__ url_for
    def url_for(options = {})
      options = Base.relative_url_root.to_s + options if
          options.kind_of?(String) and options.starts_with?('/')
      url_for__ptsroot__(options)
    end
    alias redirect_to__ptsroot__ redirect_to
    def redirect_to(options = {})
      options = Base.relative_url_root.to_s + options if
          options.kind_of?(String) and options.starts_with?('/')
      redirect_to__ptsroot__(options)
    end
  end
end
module ActionView
  module Helpers
    module UrlHelper
      alias url_for__ptsroot__ url_for
      def url_for(options = {})
        return escape_once(
            ::ActionController::Base.relative_url_root.to_s + options) if
            options.kind_of?(String) and options.starts_with?('/')
        url_for__ptsroot__(options)
      end
    end
  end
end