Nils Franzén

Jun 30

Global Gaming Factory is buying The Pirate Bay and Peerialism

Now it is public, we (Peerialism) and The Pirate Bay is getting bought by Global Gaming Factory.

http://www.aktietorget.se/NewsItem.aspx?ID=52051 (in Swedish)

Jan 04

Using Google Federated Login in your Rails Application

I’m in the progress of building an Android application with a Ruby on Rails backend. On Android, one of the first things you need to do is to tie the phone to a Google account. So to make it easier for the end users, I thought that I maybe could skip my own user account management and instead piggy back on the Google accounts.

After some initial research I found that Google recently released a single sign-on using OpenID. There are some sites that use the Google Federated Login, e.g. www.zoho.com, www.buxfer.com and http://www.plaxo.com/openid (look for the Google login button). However, it turned out that it wasn’t really OpenID, it was something that resembles of OpenID. Even thought it isn’t pure OpenID, it does everything I want anyway, so I started to code the login using the “official” OpenID Authentication plugin.

From Google Federated Login you can currently only get the email of a user, but it was impossible to get the email using the OpenID Authentication plugin. After some detective work it was clear that Google Federated Login uses AX attributes, not the SReg attributes that is used by default in the plugin. So my solution is to patch the plugin with the code below. You can add the code to your session controller and it will work with the Google OpenID URI.

  #
  # If we want to get the GMail address for a user using Google Federated Login,
  # we need to work with AX attributes, not SReg attributes which is used by
  # default.
  #
  # To solve this Ax/SReg attribute problem we patch the OpenIdAuthentication
  # module to use AX attributes when talking to the Google OpenID server
  #
  # This patch is based on the source from github[1], January 4, 2009
  #
  # 1. http://github.com/rails/open_id_authentication/commits/master
  #
  module ::OpenIdAuthentication
    require 'openid/extensions/ax'

    private
    def add_simple_registration_fields(open_id_request, fields)
      if is_google_federated_login?(open_id_request)
        ax_request = OpenID::AX::FetchRequest.new
        # Only the email attribute is currently supported by google federated login
        email_attr = OpenID::AX::AttrInfo.new('http://schema.openid.net/contact/email', 'email', true)
        ax_request.add(email_attr)
        open_id_request.add_extension(ax_request)
      else
        sreg_request = OpenID::SReg::Request.new
        sreg_request.request_fields(Array(fields[:required]).map(&:to_s), true) if fields[:required]
        sreg_request.request_fields(Array(fields[:optional]).map(&:to_s), false) if fields[:optional]
        sreg_request.policy_url = fields[:policy_url] if fields[:policy_url]
        open_id_request.add_extension(sreg_request)
      end
    end

    def complete_open_id_authentication
      params_with_path = params.reject { |key, value| request.path_parameters[key] }
      params_with_path.delete(:format)
      open_id_response = timeout_protection_from_identity_server { open_id_consumer.complete(params_with_path, requested_url) }
      identity_url     = normalize_identifier(open_id_response.display_identifier) if open_id_response.display_identifier

      case open_id_response.status
      when OpenID::Consumer::SUCCESS
        if is_google_federated_login?(open_id_response)
          yield Result[:successful], params['openid.identity'], OpenID::AX::FetchResponse.from_success_response(open_id_response)
        else
          yield Result[:successful], identity_url, OpenID::SReg::Response.from_success_response(open_id_response)
        end
      when OpenID::Consumer::CANCEL
        yield Result[:canceled], identity_url, nil
      when OpenID::Consumer::FAILURE
        yield Result[:failed], identity_url, nil
      when OpenID::Consumer::SETUP_NEEDED
        yield Result[:setup_needed], open_id_response.setup_url, nil
      end
    end

    def is_google_federated_login?(request_response)
      return request_response.endpoint.server_url == "https://www.google.com/accounts/o8/ud"
    end
  end

And in the create method (following the example given in the README for the plugin), I have currently hard-coded the OpenID URI to ‘https://www.google.com/accounts/o8/id’, but you could get it from a form as well. Note that we have two cases to get the email depending if a Google OpenID URI or a regular OpenID URI was used.

  def create
    openid_url = 'https://www.google.com/accounts/o8/id'
    authenticate_with_open_id(openid_url, {:required => [ 'email' ] }) do |result, identity_url, registration|
      case result.status
      when :missing
        failed_login "Sorry, the OpenID server couldn't be found"
      when :invalid
        failed_login "Sorry, but this does not appear to be a valid OpenID"
      when :canceled
        failed_login "OpenID verification was canceled"
      when :failed
        failed_login "Sorry, the OpenID verification failed"
      when :successful
        if registration.class.to_s == "OpenID::AX::FetchResponse"
          email = registration['http://schema.openid.net/contact/email']
        else
          email = registration['email']
        end
        # Find (or create user) based on identity_url
        # Note that email is not set when the user has selected 'always remember' in the Google login page for subsequent logins
      end
    end
  end

Update January 9: The code was updated to solve the Google ‘always remember’ problem
Update January 15: The most important technical issue in using the Google Federated Login API

Sep 06

An indispensable bash function for Cygwin

cygwin 2 Comments »

Put the following code in your .bashrc file:

function open()
{
   if [ "$1" = "" ]
   then
     rundll32 url.dll,FileProtocolHandler .
  else
      rundll32 url.dll,FileProtocolHandler `cygpath -w "$1"`
   fi
}

Now you can use the open command.

Type open http://www.franzens.org to fire up your web browser and point it to this site.
Type open some_document.doc to start Microsoft Word (or Open Office) with specified document.
Type open some_document.txt to start notepad with specified document.
Type open to launch the explorer in current directory.
Type open //some_network_path/foo/bar to launch the explorer in specified directory.

I think you see the pattern above. I use the open command all the time and it is really useful.

May 12

Visualize Models 1.1

rails 8 Comments »

Visualize Models is a small rake script that will generate .png images for Ruby On Rails models (i.e. the database tables) that will display the table/column information. The associations between tables is based on the default Ruby On Rails naming convention (i.e. <table>_id columns). See image below for the typo blog models: