OAuth Plugin

This is a plugin for implementing OAuth Providers and Consumers in Rails applications.

We support the revised OAuth 1.0a specs at:

oauth.net/core/1.0a

and the OAuth site at:

oauth.net

For more about the changes made to OAuth1.0a please see Seth’s Idiot’s Guide to OAuth 1.0a.

mojodna.net/2009/05/20/an-idiots-guide-to-oauth-10a.html

Requirements

You need to install the oauth gem (0.3.5) which is the core OAuth ruby library. It will NOT work on any previous version of the gem.

  sudo gem install oauth

Installation

The plugin can now be installed as an gem from github, which is the easiest way to keep it up to date.

  sudo gem install oauth-plugin

You should add the following in the gem dependency section of environment.rb

  config.gem "oauth"
  config.gem "oauth-plugin"

Alternatively you can install it in vendors/plugin:

  script/plugin install git://github.com/pelle/oauth-plugin.git

The Generator currently creates code (in particular views) that only work in Rails 2.

It should not be difficult to manually modify the code to work on Rails 1.2.x

I think the only real issue is that the views have .html.erb extensions. So these could theoretically just be renamed to .rhtml.

Please let me know if this works and I will see if I can make the generator conditionally create .rhtml for pre 2.0 versions of RAILS.

OAuth Provider generator

While it isn’t very flexible at the moment there is an oauth_provider generator which you can use like this:

  ./script/generate oauth_provider

This generates OAuth and OAuth client controllers as well as the required models.

It requires an authentication framework such as acts_as_authenticated, restful_authentication or restful_open_id_authentication. It also requires Rails 2.0.

Generator Options

By default the generator generates RSpec and ERB templates. The generator can instead create Test::Unit and/or HAML templates. To do this use the following options:

  ./script/generate oauth_provider --test-unit --haml

These can of course be used individually as well.

User Model

Add the following lines to your user model:

  has_many :client_applications
  has_many :tokens, :class_name=>"OauthToken",:order=>"authorized_at desc",:include=>[:client_application]

Migrate database

The database is defined in:

  db/migrate/XXX_create_oauth_tables.rb

Run them as any other normal migration in rails with:

  rake db:migrate

Upgrading from OAuth 1.0 to OAuth 1.0a

As the flow has changed slightly and there are a couple of database changes it isn’t as simple as just updating the plugin. Please follow these steps closely:

Add a migration

You need to add a migration:

  script/generate migration upgrade_oauth

Make it look like this:

  class UpgradeOauth < ActiveRecord::Migration
    def self.up
      add_column :oauth_tokens,:callback_url,:string
      add_column :oauth_tokens,:verifier,:string,:limit => 20
    end

    def self.down
      remove_column :oauth_tokens,:callback_url
      remove_column :oauth_tokens,:verifier
    end
  end

Change code

There are changes to the following files:

  app/models/client_application.rb
  app/models/request_token.rb
  app/controllers/oauth_controller.rb

Changes in client_application.rb

Add the following towards the top of the model class

  attr_accessor :token_callback_url

Then change the create_request_token method to the following:

  def create_request_token
    RequestToken.create :client_application =>self,:callback_url=>token_callback_url
  end

Changes in request_token.rb

The RequestToken contains the bulk of the changes so it’s easiest to list it in it’s entirety. Mainly we need to add support for the oauth_verifier parameter and also tell the client that we support OAuth 1.0a.

Make sure it looks like this:

  class RequestToken < OauthToken

    attr_accessor :provided_oauth_verifier

    def authorize!(user)
      return false if authorized?
      self.user = user
      self.authorized_at = Time.now
      self.verifier=OAuth::Helper.generate_key(16)[0,20] unless oauth10?
      self.save
    end

    def exchange!
      return false unless authorized?
      return false unless oauth10? || verifier==provided_oauth_verifier

      RequestToken.transaction do
        access_token = AccessToken.create(:user => user, :client_application => client_application)
        invalidate!
        access_token
      end
    end

    def to_query
      if oauth10?
        super
      else
        "#{super}&oauth_callback_confirmed=true"
      end
    end

    def oob?
      self.callback_url=='oob'
    end

    def oauth10?
      (defined? OAUTH_10_SUPPORT) && OAUTH_10_SUPPORT && self.callback_url.blank?
    end

  end

Changes in oauth_controller

All you need to do here is the change the authorize action to use the request_token callback url and add the oauth_verifier to the callback url.

  def authorize
    @token = ::RequestToken.find_by_token params[:oauth_token]
    unless @token.invalidated?
      if request.post?
        if params[:authorize] == '1'
          @token.authorize!(current_user)
          if @token.oauth10?
            @redirect_url = params[:oauth_callback] || @token.client_application.callback_url
          else
            @redirect_url = @token.oob? ? @token.client_application.callback_url : @token.callback_url
          end

          if @redirect_url
            if @token.oauth10?
              redirect_to "#{@redirect_url}?oauth_token=#{@token.token}"
            else
              redirect_to "#{@redirect_url}?oauth_token=#{@token.token}&oauth_verifier=#{@token.verifier}"
            end
          else
            render :action => "authorize_success"
          end
        elsif params[:authorize] == "0"
          @token.invalidate!
          render :action => "authorize_failure"
        end
      end
    else
      render :action => "authorize_failure"
    end
  end

Alternatively if you haven’t customized your controller you can replace the full controller with this:

  require 'oauth/controllers/provider_controller'
  class OauthController < ApplicationController
    include OAuth::Controllers::ProviderController
  end

This way the controller will automatically include bug fixes in future versions of the plugin.

The rest of the changes are in the plugin and will be automatically be included.

Note OAuth 1.0a removes support for callback url’s passed to the authorize page, clients must either define a callback url in their client application or pass one on the token request page.

Supporting old OAuth 1.0 clients

If you absolutely have to support older OAuth 1.0 clients on an optional basis, we now include a switch to turn it back on.

For legacy OAUTH 1.0 support add the following constant in your environment.rb

  OAUTH_10_SUPPORT = true

Note, you should only do this if you really positively require to support old OAuth1.0 clients. There is a serious security issue with this.

Protecting your actions

I recommend that you think about what your users would want to provide access to and limit oauth for those only. For example in a CRUD controller you may think about if you want to let consumer applications do the create, update or delete actions. For your application this might make sense, but for others maybe not.

If you want to give oauth access to everything a registered user can do, just replace the filter you have in your controllers with:

  before_filter :login_or_oauth_required

If you want to restrict consumers to the index and show methods of your controller do the following:

  before_filter :login_required,:except=>[:show,:index]
  before_filter :login_or_oauth_required,:only=>[:show,:index]

If you have an action you only want used via oauth:

  before_filter :oauth_required

All of these places the tokens user in current_user as you would expect. It also exposes the following methods:

• current_token - for accessing the token used to authorize the current request
• current_client_application - for accessing information about which consumer is currently accessing your request

You could add application specific information to the OauthToken and ClientApplication model for such things as object level access control, billing, expiry etc. Be creative and you can create some really cool applications here.

OAuth Consumer generator

The oauth_consumer generator creates a controller to manage the authentication flow between your application and any number of external OAuth secured applications that you wish to connect to.

To run it simply run:

  ./script/generate oauth_consumer

This generates the OauthConsumerController as well as the ConsumerToken model.

Generator Options

By default the generator generates ERB templates. The generator can instead create HAML templates. To do this use the following options:

  ./script/generate oauth_consumer --haml

Configuration

All configuration of applications is done in

  config/initializers/oauth_consumers.rb

Add entries to OAUTH_CREDENTIALS for all OAuth Applications you wish to connect to. Get this information by registering your application at the particular applications developer page.

  OAUTH_CREDENTIALS={
    :twitter=>{
      :key=>"key",
      :secret=>"secret"
    },
    :agree2=>{
      :key=>"key",
      :secret=>"secret"
    },
    :hour_feed=>{
      :key=>"",
      :secret=>"",
      :options={
        :site=>"http://hourfeed.com"
      }
    },
    :nu_bux=>{
      :key=>"",
      :secret=>"",
      :super_class=>"OpenTransactToken",  # if a OAuth service follows a particular standard
                                          # with a token implementation you can set the superclass
                                          # to use
      :options=>{
        :site=>"http://nubux.heroku.com"
      }
    }
  }

You can add any of the options that the OAuth::Consumer.new accepts to the options hash: oauth.rubyforge.org/rdoc/classes/OAuth/Consumer.html

:key, :secret are required as well as :options[:site] etc. for non custom ConsumerToken services.

ConsumerToken models

For each site setup in the OAUTH_CREDENTIALS hash the plugin goes through and loads or creates a new model class that subclasses ConsumerToken.

eg. If you connect to Yahoo’s FireEagle you would add the :fire_eagle entry to OAUTH_CREDENTIALS and a new FireEagleToken model class will be created on the fly.

This allows you to add a has_one association in your user model:

  has_one  :fire_eagle,:class_name=>"FireEagleToken", :dependent=>:destroy

And you could do:

  @location=@user.fire_eagle.client.location

The client method gives you a OAuth::AccessToken which you can use to perform rest operations on the client site - see oauth.rubyforge.org/rdoc/classes/OAuth/AccessToken.html

Custom ConsumerToken models

Before creating the FireEagleToken model the plugin checks if a class already exists by that name or if we provide an api wrapper for it. This allows you to create a better token model that uses an existing ruby gem.

Currently we provide the following semi tested tokens wrappers:

• FireEagle
• Twitter
• Agree2

These can be found in lib/oauth/models/consulers/services. Contributions will be warmly accepted for your favorite OAuth service.

The OauthConsumerController

To connect a user to an external service link or redirect them to:

  /oauth_consumers/[SERVICE_NAME]

Where SERVICE_NAME is the name you set in the OAUTH_CREDENTIALS hash. This will request the request token and redirect the user to the services authorization screen. When the user accepts the get redirected back to:

  /oauth_consumers/[SERVICE_NAME]/callback

You can specify this url to the service you’re calling when you register, but it will automatically be sent along anyway.

Migrate database

The database is defined in:

  db/migrate/XXX_create_oauth_consumer_tokens.rb

Run them as any other normal migration in rails with:

  rake db:migrate

More

The Google Code project is code.google.com/p/oauth-plugin/

The Mailing List for all things OAuth in Ruby is:

groups.google.com/group/oauth-ruby

The Mailing list for everything else OAuth is:

groups.google.com/group/oauth

The OAuth Ruby Gem home page is oauth.rubyforge.org

Please help documentation, patches and testing.

Copyright © 2007-2009 Pelle Braendgaard, released under the MIT license