Omniauth Support

app/controllers/omniauth_callbacks_controller.rb

@@ -9,7 +9,7 @@ class OmniauthCallbacksController < Devise::OmniauthCallbacksController
     error ||= env["omniauth.error.type"].to_s
     error.to_s.humanize if error
   end
- 
+
   def ldap
     # We only find ourselves here if the authentication to LDAP was successful.
     info = request.env["omniauth.auth"]["info"]
@@ -20,4 +20,34 @@ class OmniauthCallbacksController < Devise::OmniauthCallbacksController
     sign_in_and_redirect @user
   end
 
+   Settings.omniauth_providers.each do |provider|
+    define_method provider['name'] do
+      handle_omniauth
+    end
+  end
+
+  private
+
+  def handle_omniauth
+    oauth = request.env['omniauth.auth']
+    provider, uid = oauth['provider'], oauth['uid']
+
+    if current_user
+      # Change a logged-in user's authentication method:
+      current_user.uid = uid
+      current_user.provider = provider
+      current_user.save
+      redirect_to profile_path
+    else
+      @user = User.find_by_provider_and_uid(provider, uid)
+
+      if @user
+        sign_in_and_redirect @user
+      else
+        flash[:notice] = "There's no such user!"
+        redirect_to new_user_session_path
+      end
+    end
+  end
+
 end