Dr. Dobb's Journal - October 2008 - (Page 43)

D10weis_p5db 8/15/08 9:40 AM Page 43 open_id_authentication/tree/master/READ ME) that uses the ruby-openid gem and makes it easy to add OpenID support to Rails applications, so I install it now: $ ./script/plugin install open_id_authentication Next, generate a User model with a few basic attributes: $ ./script/generate model user identity_url:string email:string full_name:string date_of_birth:date Next, create a session controller, which handles login (with OpenID, of course) and logout for your users: $ ./script/generate controller session new Once the plug-in is installed, run this Rake task to create a database migration: $ rake open_id_authentication:db:create This generates a migration to create a table to store users. It’s a good idea to add an index on the identity_url column because it can fetch data. To do so, add this line to the end of the up class method in the create_users migration: add_index :users, :identity_url, :unique => true If you’re curious, take a look at the migration that was created. It creates two database tables, “open_id_authentication_associations” and “open_id_authentication_nonces” which store information , about the messages received from OpenID identity providers, including authentication keys. Open app/controllers/session_controller.rb in your text editor or IDE and implement the create and destroy actions (Example 1). The destroy action stands on its own, but the create action delegates to another method, open_id_authentication (Example 2). This method has lots of responsibility, so let’s examine it: if params[:openid_url].blank? && params[:open_id_complete].blank? return failed_login("Please enter your OpenID") end Configure a development database in config/database.yml and run this Rake task to create the development database and run the migrations: $ rake db:migrate The aforementioned condition checks that users entered an identity URI, which is accessed through params[:openid_url], (app/controllers/session_controller.rb) def failed_login(message) flash.now[:error] = message render :action => 'new' end Example 3: Handling a login failure. # Maps OpenID sreg keys to fields of your user model. # registration is a hash containing valid sreg keys def assign_registration_attributes(user, registration) { :email => 'email', :date_of_birth => 'dob', :full_name => 'fullname' }.each do |model_attr, registration_attr| unless registration[registration_attr].blank? user.send "#{model_attr}=", registration[registration_attr] end end user.save end Example 4: Assigning sreg attributes to new users. class ApplicationController < ActionController::Base helper_method :current_user protected # Accesses the current user from the session. def current_user @current_user ||= (session[:user_id] && User.find_by_id(session[:user_id])) end # Store the given user in the session. def current_user=(new_user) session[:user_id] = new_user && new_user.id @current_user = new_user end end Example 5: Managing the current user’s session. October 2008 l www.ddj.com l Dr. Dobb’s Journal 43 http://github.com/rails/open_id_authentication/tree/master/README http://github.com/rails/open_id_authentication/tree/master/README http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - October 2008

Dr. Dobb's Journal - October 2008 Contents Friday Night Fish Fry Alia Vox Developer Diaries Developer’s Notebook Is Your Next Language COBOL? Conversations Safe Coding Practices Code Signing in Adobe AIR OpenID Single Sign-On The Book Cipher Algorithm Indexing and Searching Image files Extending Continuous Integration Into ALM The Agile Edge Effective Concurrency Swaine’s Flames

Dr. Dobb's Journal - October 2008

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