Project: simple_facebook_connect

Simple Facebook Connect

This plugin adds the ability to sign in/sign up using facebook connect to your Rails application.

Disclaimer

Most of the code here is a direct rip-off of the facebooker gem. We wanted something much simpler than facebooker so we took the code we needed, refactored and changed bits and pieces and here we are.

Basic process

With this plugin you will add the well know facebook connect button to your site. When a visitor clicks on it:

she will be redirected to facebook
after signing in at facebook be directed back to your signup page
there she will sign up as usual but without being asked to enter a password
after signing up she will be able to sign into your site by clicking the facebook connect button

When an existing user of your site clicks the button he will also be able to log in via facebook, given the email address he signed up with at your site is also known to facebook.

Set up a facebook application

For basic application setup see the facebook developer documentation.

Set the "Canvas Callback URL" to "http://your.server.com/fb/connect" and the "Connect URL" to "http://your.server.com". Write down the API and secret key for later.

Installation

This plugin assumes you have a User model with an email attribute. It will add some extensions to your User model and controllers in order to provide the necessary hooks and calls for facebook to authenticate your users.

Install the gem:

sudo gem install simple_facebook_connect --source=http://gemcutter.org

Add it as a dependency to your Rails application:

# environment.rb
gem 'simple_facebook_connect', :source => 'http://gemcutter.org'

Run the migration generator and migrate:

script/generate simple_facebook_connect_migration
rake db:migrate
rake db:test:clone

In the meantime we have created a RAILS_ROOT/config/simple_facebook_connect.yml file in which you should enter your facebook API and secret keys.

After that add the facebook connect button to your sign up and/or sign in pages. We have prepared a partial for you:

<%= render :partial => 'shared/facebook_connect_button' %>

Add this to your signup action (users/create in most cases):

class UsersController < ApplicationController
  def create
    @user = # initialize user
    ....
    @user.fb_uid = facebook_user.uid if facebook_user
    @user.save
  end
end

Change your signup form to not show any password fields when signing up via facebook:

<%- unless facebook_user -%>
  <%= f.password_field :password -%>
  ...
<%- end -%>

Provide a log_in(user) method, either in your ApplicationController or by subclassing SimpleFacebookConnect::ConnectController:

class AppicationController < ActionController::Base

  ...
  
  private
  
  def log_in(user)
    session[:user_id] = user.id # or whatever your app does
    redirect_to account_path
  end
end

Make your User model Facebook aware:

class User
  facebook_user
  
  ...
end

Optional step (well, you really should do this): Generate Cucumber Features:

script/generate simple_facebook_connect_features

This will generate a feature, step definitions and fixtures to test the facebook connect integration. You will probably have to adjust those files to fit your app, for example we are using Machinist to generate User instances.

Finally: run the features and by now everything should be green. Congrats.

What else

You can grab some of the facebook profile data (e.g. name, location, picture) when signing up your new users. For a complete list of attributes see SimpleFacebookConnect::User::FIELDS. In order to do that you could add a line of code to your signup action:

class UsersController < ApplicationController
  def create
    @user = # initialize user
    ....
    if facebook_user
      @user.name = facebook_user.name
      @user.about_me = facebook_user.about_me
    end
    @user.save
  end
end