How to logout completely from Facebook using Ruby on Rails and Devise + Omniauth. I'm just modifying the Omniauth Railscast http://railscasts.com/episodes/236-omniauth-part-2

application.html.erb

<div id="user_nav">
     <% if user_signed_in? %>
          <img src="<%= user_avatar %>" id="main_avatar"> Signed in as <%= current_user.email %>.<br />
          Not you? 
		
          <% if session[:fb_token].nil? %>
               <%= link_to "Sign out", destroy_user_session_path %>
          <% else %>
               <%= link_to "Sign out", facebook_logout_path %>
          <% end %>
     <% else %>
          <%= link_to "Sign In", new_user_session_path %>
          <%= link_to "Sign Up", new_user_registration_path %>
     <% end %>
</div>

application_controller.rb

  def facebook_logout
    split_token = session[:fb_token].split("|")
    fb_api_key = split_token[0]
    fb_session_key = split_token[1]
    redirect_to "http://www.facebook.com/logout.php?api_key=#{fb_api_key}&session_key=#{fb_session_key}&confirm=1&next=#{destroy_user_session_url}";
  end

authentications_controller.rb

class Users::AuthenticationsController < BaseController
  layout false

  def create
    omniauth = request.env["omniauth.auth"]
    session[:fb_token] = omniauth["credentials"]["token"] if omniauth['provider'] == 'facebook'

    # ... Same as Railscast ... #

  end
  
  def failure
    render :text => "Login Failure!"
  end
  
end

routes.rb

  match '/auth/facebook/logout' => 'application#facebook_logout', :as => :facebook_logout
  match '/auth/:provider/callback' => 'users/authentications#create'
  match '/auth/failure' => 'users/authentications#failure'

  devise_for :users, 
             :controllers => {:registrations => 'users/registrations', :sessions => 'users/sessions'}

sessions_controller.rb

class Users::SessionsController < Devise::SessionsController
  
  def destroy
    super
    session[:fb_token] = nil
  end
  
end

I believe for "my_key" above, you can find it with, for the facebook example, Devise.omniauth_configs[:facebook].args[0].

Yes, you are right, thanks for that. The access token actually consists of 3 parts: app_id "|" session_key "|" digest
http://www.quora.com/Do-the-OAuth2-access-tokens-in-the-new-Facebook-Graph-API-expire

I've updated the code accordingly.

Thanks, worked fine so far.

It no longer works... Now fb returns omniauth["credentials"]["token"] as a single string...

access_key is changed to access_token. And now you have to pass full access-token instead the split

session_key is same. It your Application secret key.

https://www.facebook.com/logout.php?access_token=xx&session_key=yy

Cheers

Hi Rameshv,
I have tried the above solution, but it didn't worked for me.
I am passing the access_token stored in session i.e omniauth["credentials"]["token"] and the app secret key, but still it does not logout from my facebook account.
I am using rails 2.3.11, ruby 1.8.7, omniauth 0.1.6
Any help is appreciated.

Thanks
Anita Bharambe

I got success doing a GET to this URL

https://www.facebook.com/logout.php?next=http://example.com&access_token=xxx

The access_token is the returned by facebook, in the example the omniauth["credentials"]["token"].

Reference 1

Hi,

Is there any way to redirect to the app than redirecting to the facebook page, once its logged out.

Thanks.

@1mrankhan Yes, use the url param named next in your redirect_to url

See line 5 in this example : https://gist.github.com/rdetert/848721#file-application_controller-rb-L5

redirect_to "http://www.facebook.com/logout.php?api_key=#{fb_api_key}&session_key=#{fb_session_key}&confirm=1&next=#{destroy_user_session_url}"
                                                                                                              ^^^^

This problem took me one day. All information was scattered around the web and was focused only on single Facebook login. I needed also to login with local and other social media accounts. So this is my working solution, hope it helps someone:

in applicatoin.html.erb:
change:

<% else %> 
     <%= link_to "Sign out", facebook_logout_path %>
<% end %>

to

<% else %>
  <% if session[:fb_token].nil? %>
        <li><%= link_to "Sign out", facebook_logout_path %></li>
  <% else %>
        <li> <%= link_to "Sign out", facebook_logout_path, id: "sign_out_fb" %></li>
  <% end %>
<% end %>

make file app/javascript/facebook.js.coffee.erb

jQuery ->
  $('body').prepend('<div id="fb-root"></div>')

  $.ajax
    url: "#{window.location.protocol}//connect.facebook.net/en_US/all.js"
    dataType: 'script'
    cache: true

window.fbAsyncInit = ->
  FB.init(appId: '<%= ENV["FACEBOOK_APP_ID"] %>', cookie: true)

  $('#sign_in_fb').click (e) ->
    e.preventDefault()
    FB.login (response) ->
      window.location = '/auth/facebook/callback' if response.authResponse

  $('#sign_out_fb').click (e) ->
    FB.getLoginStatus (response) ->
       FB.logout() if response.authResponse
    true

generate the devise views:

$ rails g devise:views User

in user/shared/_links.html.erb

change:

<%- resource_class.omniauth_providers.each do |provider| %>
     <%= link_to "Sign in with #{OmniAuth::Utils.camelize(provider)}", omniauth_authorize_path(resource_name, provider) %><br />
<% end %>

to

<%- resource_class.omniauth_providers.each do |provider| %>
    <% if provider == 'facebook'%>
      <%= link_to "Sign in with #{OmniAuth::Utils.camelize(provider)}", omniauth_authorize_path(resource_name, provider), id: "sign_in_fb" %><br />
    <% else %>
      <%= link_to "Sign in with #{OmniAuth::Utils.camelize(provider)}", omniauth_authorize_path(resource_name, provider) %><br />
    <% end %>
  <% end -%>

notes

• I had to add , :method => :delete at the end of both <%= link_to "Sign out" ...... %> lines

A simple way to logout from facebook from your app's server side is to redirect it to facebook.com/logout
In logout method, add
redirect_to "https://www.facebook.com/logout.php?next=#{redirection_url}&access_token=#{fb_token}"
where, redirection url, is the url where facebook would redirect/callback after logout. For example, "http://www.example.com:3000/thankyou"
fb_token, is the token you get from auth_hash['credentials']['token'] , where auth_hash = request.env['omniauth.auth']

PS: omniauth-facebook gem is being used here (https://github.com/mkdynamic/omniauth-facebook)

Thanks
Devyani@livvel