Authlogic RPX

Purpose

Authlogic RPX is an Authlogic extension library that provides support for authentication using the RPX multi-authentication service offered by JanRain. To use RPX, you must first register your application at RPX. A free “Basic” account is available, in addition to paid enhanced versions. All work with Authlogic_RPX.

Key features and capabilities:

  • Auto-registration by default following RPX authentication (can be disabled if required)

  • Can allow users to enable RPX authentication for their existing password-enabled accounts

  • View helpers to assist with inserting login fragments in pages

  • Can co-exist with standard password authentication

Authlogic_RPX References

* Authlogic_RPX gem repo: [github.com/tardate/authlogic_rpx] * Authlogic_RPX issues and feedback: [github.com/tardate/authlogic_rpx/issues]

The demonstration Rails application is where you can see Authlogic_RPX in action:

Authlogic and RPX References

* Authlogic documentation: [rdoc.info/projects/binarylogic/authlogic] * Authlogic repo: [github.com/binarylogic/authlogic] * RPX documentation: [rpxnow.com/docs] * RPX_now gem repo: [github.com/grosser/rpx_now]

Installing Authlogic RPX gem

Three gems are required: authlogic, grosser-rpx_now, and authlogic_rpx. Install these as appropriate to your environment and preferences.

Currently tested versions:

  • authlogic 2.1.2,2.1.1

  • rpx_now 0.6.6

  • authlogic_rpx 1.0.4

1. Direct gem installation

sudo gem install authlogic
sudo gem install rpx_now --source http://gemcutter.org
sudo gem install authlogic_rpx --source http://gemcutter.org

2. Using Rails config.gems

Include in config/environment.rb:

config.gem 'authlogic', :version => '>= 2.1.1'
config.gem 'rpx_now', :version => '>= 0.6.6', :source => 'http://gemcutter.org'
config.gem 'authlogic_rpx', :version => '>= 1.0.4', :source => 'http://gemcutter.org'

Then to install, run from the command line:

sudo rake gems:install

3. Using .gems file (e.g for heroku.com deployments)

Include in RAILS_ROOT/.gems:

authlogic --version '>= 2.1.1'
rpx_now --version '>= 0.6.6' --source gemcutter.org
authlogic_rpx --version '>= 1.0.4' --source gemcutter.org

Using Authlogic RPX

Note: in what follows, the user model is called User and the session controller takes the name UserSession (the authlogic convention). You are not restricted to these names - could be Member and MemberSession for example - but for simplicity, this documentation will stick to using the “User” convention.

Using Authlogic RPX is very similar to using standard authlogic, with the addition of just a few configuration options. So if you already have a project setup with authlogic, adding RPX support will be trivial.

An important capability to be aware of is “auto registration”. This means that when a user has logged in with RPX, if an account does not already exist in your application, it will be automatically created. That is, there is no separate/special “register” step for users to go through before just signing in. You can disable this if you need, but for most sites that use RPX as a primary authentication mechanism, this is probably what you want to happen.

The main steps for enabling Authlogic RPX:

    1. Enable RPX for your user model

    1. Add RPX configuration for the Authlogic session model

    1. Add custom user profile mapping (optional)

    1. Add application controller helpers: current_user, current_user_session

    1. Setup the Authlogic session controller

    1. Setup the Authlogic user controller

    1. Use view helpers to provide login links

    1. Allow users to “Add RPX” to existing accounts (optional)

1. Enable RPX for your user model

The user model requires an additional field called “rpx_identifier”. Creat a migration to add this. You may need to remove database constraints on other fields if they will be unused in the RPX case (e.g. crypted_password and password_salt to make password authentication optional).

If you are using auto-registration, you must also remove any database constraints for fields that will be automatically mapped (see notes in “3. Add custom user profile mapping during auto-registration”)

class AddUsersRpxIdentifier < ActiveRecord::Migration
  def self.up
    add_column :users, :rpx_identifier, :string
    add_index :users, :rpx_identifier

    change_column :users, :crypted_password, :string, :default => nil, :null => true
    change_column :users, :password_salt, :string, :default => nil, :null => true

  end

  def self.down
    remove_column :users, :rpx_identifier

    [:crypted_password, :password_salt].each do |field|
      User.all(:conditions => "#{field} is NULL").each { |user| user.update_attribute(field, "") if user.send(field).nil? }
      change_column :users, field, :string, :default => "", :null => false
    end
  end
end

The user model then needs to be tagged with “acts_as_authentic”, and you must add rpx_identifier to the attr_accessible configuration (if you are using it)

class User < ActiveRecord::Base
  acts_as_authentic do |c|
    c.my_config_option = my_value # for available options see documentation in: Authlogic::ActsAsAuthentic
  end # block optional
  attr_accessible :username, :email, :password, :password_confirmation, :rpx_identifier
end

See the source for the sample user.rb.

2. Add RPX configuration for the Authlogic session model

Authlogic provides a helper to create the session model:

script/generate session user_session

The minimum configuration required is to add your RPX_API_KEY:

class UserSession < Authlogic::Session::Base
	rpx_key RPX_API_KEY
end

Get an API key by registering your application at RPX. A free “Basic” account is available, in addition to paid enhanced versions. All work with Authlogic_RPX.

You probably don’t want to put your API key in directly. A recommended approach is to set the key as an environment variable, and then set it as a constant in config/environment.rb:

RPX_API_KEY = ENV['RPX_API_KEY']

Two additional RPX-specific session configuration options are available.

  • auto_register: enable/disable user auto-registration (enabled by default)

  • rpx_extended_info: enable/disable extended profile information in the RPX authentication (disabled by default)

For example, to disable auto-registration and enable extended info:

class UserSession < Authlogic::Session::Base
	rpx_key RPX_API_KEY
	auto_register false
	rpx_extended_info
end

See the source for the sample user_session.rb.

3. Add custom user profile mapping (optional)

Authlogic_rpx provides three hooks for mapping information from the RPX profile into your application’s user model:

  • map_rpx_data: user profile mapping during auto-registration

  • map_rpx_data_each_login: user profile mapping during login

  • map_added_rpx_data: user profile mapping when adding RPX to an existing account

See rpxnow.com/docs#profile_data for the definition of available attributes in the RPX profile.

3a. map_rpx_data: user profile mapping during auto-registration

When users auto-register, profile data from RPX is available to be inserted in the user’s record on your site. By default, authlogic_rpx will map the username and email fields.

If you have other fields you want to map, you can provide your own implementation of the map_rpx_data method in the UserSession model. In that method, you will be updating the “self.attempted_record” object, with information from the “@rpx_data” object. See the RPX documentation to find out about the set of information that is available. 

class UserSession < Authlogic::Session::Base
	rpx_key RPX_API_KEY
	rpx_extended_info
	
private

  # map_rpx_data maps additional fields from the RPX response into the user object
  # override this in your session controller to change the field mapping
  # see https://rpxnow.com/docs#profile_data for the definition of available attributes
  #
  def map_rpx_data
    # map core profile data using authlogic indirect column names
    self.attempted_record.send("#{klass.}=", @rpx_data['profile']['preferredUsername'] ) if attempted_record.send(klass.).blank?
    self.attempted_record.send("#{klass.email_field}=", @rpx_data['profile']['email'] ) if attempted_record.send(klass.email_field).blank?

    # map some other columns explicitly
    self.attempted_record.fullname = @rpx_data['profile']['displayName'] if attempted_record.fullname.blank?

  	if rpx_extended_info?
  		# map some extended attributes
  	end
  end
	
end

See the source for the sample user_session.rb.

WARNING: if you are using auto-registration, any fields you map should NOT have constraints enforced at the database level. Authlogic_rpx will optimistically attempt to save the user record during registration, and violating a database constraint will cause the authentication/registration to fail.

You can/should enforce any required validations at the model level e.g.

validates_uniqueness_of   :username, :case_sensitive => false

This will allow the auto-registration to proceed, and the user can be given a chance to rectify the validation errors on your user profile page.

If it is not acceptable in your application to have user records created with potential validation errors in auto-populated fields, you will need to override map_rpx_data and implement whatever special handling makes sense in your case. For example:

  • directly check for uniqueness and other validation requirements

  • automatically “uniquify” certain fields like username

  • save conflicting profile information to “pending user review” columns or a seperate table

3b. map_rpx_data_each_login: user profile mapping during login

map_rpx_data_each_login provides a hook to allow you to map RPX profile information every time the user logs in.

By default, nothing is mapped. If you have other fields you want to map, you can provide your own implementation of the map_rpx_data_each_login method in the UserSession model.

This would mainly be used to update relatively volatile information that you are maintaining in the user model (such as profile image url)

In the map_rpx_data_each_login procedure, you will be writing to fields of the “self.attempted_record” object, pulling data from the @rpx_data object. For example: def map_rpx_data_each_login # we’ll always update photo_url self.attempted_record.photo_url = @rpx_data[‘photo’] end

See the source for the sample user_session.rb.

3c. map_added_rpx_data: user profile mapping when adding RPX to an existing account

map_added_rpx_data maps additional fields from the RPX response into the user object during the “add RPX to existing account” process.

By default, it only maps the rpx_identifier field. If you have other fields you want to map, you can provide your own implementation of the map_added_rpx_data method in the User model (NOT UserSession, unlike for map_rpx_data and map_rpx_data_each_login).

NB: If you override this method, you will be responsible for also mapping the rpx_identifier.

In the map_added_rpx_data procedure, you will be writing to fields of the “self” object, pulling data from the rpx_data parameter. For example:

def map_added_rpx_data( rpx_data ) self.rpx_identifier = rpx_data[‘identifier’]

# map some additional fields, e.g. photo_url self.photo_url = rpx_data[‘photo’] if photo_url.blank? end

See the source for the sample user.rb.

4. Add application controller helpers: current_user, current_user_session

We’ll add current_user and current_user_session helpers. These can then be used in controllers and views to get a handle on the “current” logged in user.

class ApplicationController < ActionController::Base
  helper :all # include all helpers, all the time
  protect_from_forgery # See ActionController::RequestForgeryProtection for details

  # Scrub sensitive parameters from your log
  filter_parameter_logging :password, :password_confirmation

  helper_method :current_user, :current_user_session

  private

	def current_user_session
		return @current_user_session if defined?(@current_user_session)
		@current_user_session = UserSession.find
	end

	def current_user
		return @current_user if defined?(@current_user)
		@current_user = current_user_session && current_user_session.record
	end
end

See the source for the sample user_session_controller.rb.

5. Setup the Authlogic session controller

If you don’t already have a user session controller, create one. There are four actions of significance for authlogic_rpx:

$ script/generate controller user_sessions index new create destroy

See the source for the sample user_session_controller.rb.

In config/routes.rb we can define the standard routes for this controller and two named routes for the main login/out (or singin/out if you prefer that terminology):

map. "signin", :controller => "user_sessions", :action => "new"
map.signout "signout", :controller => "user_sessions", :action => "destroy"
map.resources :user_sessions

index

This is where RPX will return to if the user cancelled the login process, so it needs to be handled. You probably just want to redirect the user to an appropriate alternative:

def index redirect_to current_user ? root_url : new_user_session_url end

new

Typically used to render a login form

def new @user_session = UserSession.new end

create

This is where the magic happens for authentication. Authlogic hides all the underlying wiring, and you just need to “save” the session!

Authlogic_rpx provides two additional methods that you might want to use to tailor you application behaviour:

  • new_registration? - if a new registration, e.g. force them to go via a registration follow-up page

  • registration_complete? - if registration details not complete, e.g. bounce the user over the profile editing page

def create @user_session = UserSession.new(params) if @user_session.save if @user_session.new_registration? flash = “Welcome! As a new user, please review your registration details before continuing..” redirect_to edit_user_path( :current ) else if @user_session.registration_complete? flash = “Successfully signed in.” redirect_back_or_default articles_path else flash = “Welcome back! Please complete required registration details before continuing..” redirect_to edit_user_path( :current ) end end else flash = “Failed to login or register.” redirect_to new_user_session_path end end

destroy

The logout action..

def destroy @user_session = current_user_session @user_session.destroy if @user_session flash = “Successfully signed out.” redirect_to articles_path end

6. Setup the Authlogic user controller

The users controller handles the actual user creation and editing actions. In it’s standard form, it looks like any other controller with an underlying ActiveRecord model.

There are five basic actions to consider. If you don’t already have a controller, create it:

$ script/generate controller users new create edit show update

See the source for the sample users_controller.rb.

The users controller just needs standard routes defined in config/routes.rb:

map.resources :users

new

Stock standard form for a user to register on the site. Only required if you will allow users to register without using RPX auto-registration (using standard password authentication).

def new @user = User.new end

create

As for new, stock standard and only required if you will allow users to register without using RPX auto-registration.

def create @user = User.new(params) if @user.save flash = “Successfully registered user.” redirect_to articles_path else render :action => ‘new’ end end

show

Display’s the user’s profile. Uses the current_user helper that we’ll include in the application controller.

def show @user = current_user end

edit

Allows the user to edit their profile. Calling valid? will ensure any validation errors are highlighted. This can be relevant with RPX since auto-registration may not include all the profile data you want to make “mandatory” for normal users.

def edit @user = current_user @user.valid? end

update

Handles the submission of the edit form. Again, uses the current_user helper that we’ll include in the application controller.

def update @user = current_user @user.attributes = params if @user.save flash = “Successfully updated user.” redirect_back_or_default articles_path else render :action => ‘edit’ end end

So how to put a “login” link on your page? Two helper methods are provided:

  • rpx_popup helper to insert a link to pop-up RPX login

  • rpx_embed helper to insert an embedded iframe RPX login form

Each takes an options hash:

  • link_text: text to use in the link (only used by rpx_popup)

  • app_name: name of the application you set when registering your service at rpxnow.com (will be prepended to RPX domain and used in RPX dialogues)

  • return_url: url for the RPX callback (e.g. user_sessions_url)

  • add_rpx: Optional. If true, requests RPX callback to add to current session. Else runs normal authentication process (default). See “8. Allow users to ”Add RPX“ to existing accounts”

  • unobtrusive: true/false; sets javascript style for link. unobtrusive=true links directly to rpxnow site, whereas unobtrusive=false does a javascript pop-over. Default: true (only used by rpx_popup)

For example, to insert a login link in a navigation bar is as simple as this:

&lt;div id=“user_nav”&gt; &lt;%= link_to “Home”, root_path %&gt; | &lt;% if current_user %&gt; &lt;%= link_to “Profile”, user_path(:current) %&gt; | &lt;%= link_to “Sign out”, signout_path %&gt; &lt;% else %&gt; &lt;%= rpx_popup( :link_text => “Register/Sign in with RPX..”, :app_name => “rails-authlogic-rpx-sample”, :return_url => user_sessions_url, :unobtrusive => false ) %>&gt; &lt;% end %&gt; &lt;/div&gt;

8. Allow users to “Add RPX” to existing accounts (optional)

If you got this far and have a working application, you are ready to go, especially if you only plan to support RPX authentication.

However, if you support other authentication methods (e.g. by password), you probably want the ability to let user’s add RPX to an existing account. This is not possible by default, however adding it is simply a matter of providing another method on your user controller.

The route may be called anything you like. Let’s use “addrpxauth” for example.

# This action has the special purpose of receiving an update of the RPX identity information # for current user - to add RPX authentication to an existing non-RPX account. # RPX only supports :post, so this cannot simply go to update method (:put) def addrpxauth @user = current_user if @user.save flash = “Successfully added RPX authentication for this account.” render :action => ‘show’ else render :action => ‘edit’ end end

This is demonstrated in the sample users_controller.rb.

You’ll note this is almost identical to the “update”. The main difference is that it needs to be enabled for :post by RPX. In config/routes.rb:

map.addrpxauth "addrpxauth", :controller => "users", :action => "addrpxauth", :method => :post

To make an “Add RPX authentication for this account..” link, use rpx_popup as for normal RPX login, but set the return_url to the “addrpxauth” callback you have provided, and set the option :add_rpx to tru:

&lt;%= rpx_popup( :link_text =&gt; "Add RPX authentication for this account..", :app_name =&gt; RPX_APP_NAME, :return_url =&gt; addrpxauth_url, :add_rpx =&gt; true, :unobtrusive =&gt; false ) %&gt;

9. There is no 9

That’s all there is. To see Authlogic_RPX in action, check out the demonstration Rails application:

Improving Authlogic_RPX: next steps; how to help

Authlogic_RPX is open source and hosted on github. Developer’s are welcome to fork and play - if you have improvements or bug fixes, just send a request to pull from your fork.

If you have issues or feedback, please log them in the issues list on github

Some of the improvements currently on the radar:

  • Still figuring out how to write some good automated tests

  • Implement/verify support for RPX “paid” service features of their “Plus” and “Pro” accounts (to date, only tested with free RPX “Basic” account)

Note on programmatically grabbing an authenticated session

If you need to programmatically perform proxy authentication as a specific user (e.g. to run a batch process on behalf of the user), authlogic provides the necessary capability and this can be used with RPX-authenticated users too:

app.get "/" # force Authlogic::Session::Base.controller activation
user = User.find(:first)
session = UserSession.create(user, true) # skip authentication and log the user in directly, the true means "remember me"
session.valid?
=> true

Internals

Some design principles:

  • Attempted to stay as close to binarylogic’s “unobtrusive authentication” sensibility in Authlogic design

  • All direct RPX processing is handled in the AuthlogicRpx::Session class (not in the ActiveRecord model)

  • It uses the plug-in architecture introduced in Authlogic v2.0.

building the gem

  • increment the version in lib/authlogic_rpx/version.rb

  • update gem version refs in README.rdoc

  • update CHANGELOG.rdoc

    # update manifest file $ rake manifest # update gemspec $ rake build_gemspec # build the gem gem build authlogic_rpx.gemspec # push the gem to gemcutter (e.g. for version 1.0.3) gem push authlogic_rpx-1.0.3.gem

Kudos and Kopywrite

Thanks to binarylogic for cleaning up authentication in rails by creating Authlogic in the first place and offering it to the community.

The idea of adding RPX support to authlogic is not new. Some early ideas were found in the following projects, although it was decided not to base this implementation on a fork of these, since the approaches varied considerably: * http://github.com/hunter/authlogic_rpx an initial start, based on authlogic_openid and using rpx_now * http://github.com/gampleman/authlogic_rpx/ similar, but including an implementation of the RPX api

authlogic_rpx was created by Paul Gallagher (tardate.com) and released under the MIT license.