How to integrate Facebook Connect with a Rails app

ruby script/plugin install git://github.com/mmangino/facebooker.git

development:
  api_key: [Your KEY]
  secret_key: [Your KEY]
  canvas_page_name: playgroundrus
  callback_url: http://127.0.0.1:3000/
  pretty_errors: true
  set_asset_host_to_callback_url: false
  tunnel:
    public_host_username:
    public_host:
    public_port: 4007
    local_port: 3000
    server_alive_interval: 0
production:
  api_key: [Your KEY]
  secret_key: [Your KEY]
  canvas_page_name: playgroundrus
  callback_url: http://www.playgroundrus.com
  set_asset_host_to_callback_url: false
  tunnel:
    public_host_username:
    public_host:
    public_port: 4007
    local_port: 3000
    server_alive_interval: 0

script/generate xd_receiver

ruby script/generate migration AddFbsToUser

def self.up
  add_column :users, :fb_id, :integer
  add_column :users, :email_hash, :string
end

def self.down
  remove_column :users, :fb_id
  remove_column :users, :email_hash
end

rake db:migrate

<%= fb_connect_javascript_tag %>
<%= init_fb_connect "XFBML"%>

<%= javascript_include_tag :defaults%>

before_filter :set_facebook_session
helper_method :facebook_session

def fetch_logged_in_user
  if facebook_session
    @current_user = User.find_by_fb_user(facebook_session.user)
  else
    return unless session[:user_id]
    @current_user = User.find_by_id(session[:user_id])
  end
end

<%= fb_login_button('window.location = "/users/link_user_accounts";')%>

map.resources :users, :collection => {:link_user_accounts => :get}

after_create :register_user_to_fb

#find the user in the database, first by the facebook user id and if that fails through the email hash
def self.find_by_fb_user(fb_user)
  User.find_by_fb_id(fb_user.uid) || User.find_by_email_hash(fb_user.email_hashes)
end

#Take the data returned from facebook and create a new user from it.
#We don't get the email from Facebook and because a facebooker can only login through Connect we just generate a unique login name for them.
#If you were using username to display to people you might want to get them to select one after registering through Facebook Connect
def self.create_from_fb_connect(fb_user)
  new_facebooker = User.new(:username => "fb_#{fb_user.uid}", :password => "", :email => "")
  new_facebooker.fb_id = fb_user.uid.to_i

  #We need to save without validations
  new_facebooker.save(false)
  new_facebooker.register_user_to_fb
end

#We are going to connect this user object with a facebook id. But only ever one account.
def link_fb_connect(fb_id)
  unless fb_id.nil?
    #check for existing account
    existing_fb_user = User.find_by_fb_id(fb_id)

    #unlink the existing account
    unless existing_fb_user.nil?
      existing_fb_user.fb_id = nil
      existing_fb_user.save(false)
    end

    #link the new one
    self.fb_id = fb_id
    save(false)
  end
end

#The Facebook registers user method is going to send the users email hash and our account id to Facebook
#We need this so Facebook can find friends on our local application even if they have not connect through connect
#We hen use the email hash in the database to later identify a user from Facebook with a local user
def register_user_to_fb
  users = {:email => email, :account_id => id}
  Facebooker::User.register([users])
  self.email_hash = Facebooker::User.hash_email(email)
  save(false)
end

def facebook_user?
  return !fb_id.nil? && fb_id > 0
end

new_facebooker = User.new(:username => "fb_#{fb_user.uid}", :password => "", :email => "")

new_facebooker = User.new(:name => fb_user.name, :login => "facebooker_#{fb_user.uid}", :password => "", :email => "")

def link_user_accounts
  if @current_user.nil?
    #register with fb
    User.create_from_fb_connect(facebook_session.user)
    user = User.find_by_fb_user(facebook_session.user)
    redirect_to edit_user_path(user)
  else
    #connect accounts
    @current_user.link_fb_connect(facebook_session.user.id) unless @current_user.fb_id == facebook_session.user.id
    redirect_to playgrounds_path
  end
end

<% if @user.facebook_user? && (@user.username.nil? || @user.username =~ /fb_\d/) %>
  <% form_for @user do |f| %>

Please pick a pretty name for PlaygroundRUs: <%= f.text_field :username %>

Where do you live? (Full address, city and state, or just zip): <%= f.text_field :location %>

<%= submit_tag 'Update' %>

  <% end %>
<% else %>
<%= @user.username %>
<% form_for @user do |f| %>

Email:
    <%= f.text_field :email, :value => @user.email %>

    <% if !@user.facebook_user? %>

Password:
      <%= f.password_field :password %>

Password Confirmation:
      <%= f.password_field :password_confirmation %>

    <% end %>

Location:
    <%= f.text_field :location, :value => @user.location %>

    <%= submit_tag 'Update'%>

  <% end %>
<% end %>

def update
  @user = User.find(params[:id])
  if @user.facebook_user?
    if User.find_by_username(params[:user][:username]) || User.find_by_email(params[:user][:email])
      flash[:error] = "Username or email already exists!"
      redirect_to(edit_user_path) and return
    else
      @user.update_attribute(:username, params[:user][:username]) if params[:user][:username]
      @user.update_attribute(:location, params[:user][:location]) if params[:user][:location]
      @user.update_attribute(:email, params[:user][:email]) if params[:user][:email]
    end
  else
    @user.update_attributes(params[:user])
  end
  redirect_to user_path
end

<% if @current_user.facebook_user? %>

<%= link_to 'Edit', user_path(@current_user) %> | Logout

<% end %>

def destroy
  if @current_user.facebook_user?
    clear_fb_cookies!
    clear_facebook_session_information
  end
  session[:user_id] = nil
  @current_user = false
  redirect_to playgrounds_path
end