Separating Authentication and Identity with OmniAuth

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gem 'omniauth'

#config/intitializers/omniauth.rb 

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :twitter, 'CONSUMER_KEY', 'CONSUMER_SECRET'
  provider :facebook, 'APP_ID', 'APP_SECRET'
  provider :linked_in, 'CONSUMER_KEY', 'CONSUMER_SECRET'
end

# config/routes.rb
match '/auth/:provider/callback', :to => 'sessions#create'

rails g controller sessions

class SessionsController < ApplicationController
  def create
    render :text => request.env['rack.auth'].inspect
  end
end

rails g model authorization provider:string uid:string user_id:integer

class User < ActiveRecord::Base
  scope :authorization, ->(param) {joins(:authorizations).readonly(false).where(['authorizations.provider = ? and authorizations.uid = ?', param[:provider],param[:uid]])}

  has_many :authorizations, :dependent => :destroy

  def create_oauth_user(param= {})
    if param[:provider].present? and param[:uid].present?
      ActiveRecord::Base.transaction do
        self.save
        authorization = self.authorizations.new(provider: param[:provider], uid: param[:uid])
        authorization.save
      end
    end
  end
end

class Authorization < ActiveRecord::Base
  belongs_to :user
  validates_presence_of :user_id, :uid, :provider
  validates_uniqueness_of :uid, :scope => :provider
end

#is omniauth user
@user=User.authorization(provider: session[:omniauth],uid: session[:uid]).first and @user.present?
#create omniauth user
@user=User.new(:email => params[:email], :password => Devise.friendly_token[0,20])
@user.create_oauth_user({provider: session[:omniauth], uid: session[:uid]})#return true or false

jhjguxin/intridea-omniauth.markdown

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