#241 Simple OmniAuth

Nov 22, 2010 | 9 minutes | Plugins, Authentication

Authentication is incredibly simple to add with just OmniAuth if you don't need username/password or multiple authentications per user.

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Update 12/5/11: Some things have changed since OmniAuth version 1.0 was released. Each provider is now a separate gem that should be included in the Gemfile, and the "user_info" hash is now simply "info". The changes have been made below.

          bash
        
rails g controller sessions
rails g model user provider:string uid:string name:string
rake db:migrate

          Gemfile
        
gem 'omniauth-twitter'

          config/initializers/omniauth.rb
        
Rails.application.config.middleware.use OmniAuth::Builder do
  provider :twitter, 'CONSUMER_KEY', 'CONSUMER_SECRET'
end

          routes.rb
        
match "/auth/:provider/callback" => "sessions#create"
match "/signout" => "sessions#destroy", :as => :signout

          sessions_controller.rb
        
def create
  auth = request.env["omniauth.auth"]
  user = User.find_by_provider_and_uid(auth["provider"], auth["uid"]) || User.create_with_omniauth(auth)
  session[:user_id] = user.id
  redirect_to root_url, :notice => "Signed in!"
end

def destroy
  session[:user_id] = nil
  redirect_to root_url, :notice => "Signed out!"
end

          models/user.rb
        
def self.create_with_omniauth(auth)
  create! do |user|
    user.provider = auth["provider"]
    user.uid = auth["uid"]
    user.name = auth["info"]["name"]
  end
end

          application_controller.rb
        
helper_method :current_user

private

def current_user
  @current_user ||= User.find(session[:user_id]) if session[:user_id]
end

          rhtml
        
<% if current_user %>
  Welcome <%= current_user.name %>!
  <%= link_to "Sign Out", signout_path %>
<% else %>
  <%= link_to "Sign in with Twitter", "/auth/twitter" %>
<% end %>