Facebook API¶ ↑

A simple, lightweight Ruby library for accessing the Facebook REST API. Currently used in Facebook Connect applications, but could easily be extended for use in canvas applications.

gem install facebook_api

require 'facebook_api'

FacebookApi.configure do |config|
  config.api_key = '55e9919b8c017abe484c9fb336dffb90'
  config.secret_key 'fc881eb66493e0b845a3528c018cdd56'
  config.canvas_page_name = 'crowdfm_publisher'
  config.callback_url =  'http://crowd.fm/'
end

session = FacebookApi::Session.new(session_key, uid)

# Make REST API calls
response = session.call('Friends.get', :uid => '12345')
# Make calls with file attachments
response = session.call('Photos.upload', {:uid => '12345', :aid => '67890', :caption => 'your caption'}, File.new('/path/to/image.jpg))
# Make fql calls
response = session.call_fql('SELECT page_id FROM page_admin WHERE uid="12345"')

Both FacebookApi::Session#call and FacebookApi::Session#call_fql will generally return a hash, parsed from the JSON returned by Facebook. However, for some API calls Facebook returns non-valid JSON, usually either ‘true’, ‘false’ or a string literal (e.g. ‘12345’). In these cases, the return value from #call and #call_fql will be either true, false or the string literal respectively.

With a couple of simple methods, you can make Facebook sessions available to you in your controllers and views:

class ApplicationController < ActionController::Base
  # Requiring a valid facebook connect session for your controller actions with a before_filter:
  before_filter :require_facebook_session, :except => [:login]
  # Make the facebook_session available in your views by making it a helper_method:
  helper_method :facebook_session

  private

  def facebook_session
    @facebook_session ||= facebook_session_from_cookies
  end

  def facebook_session_from_cookies
    if FacebookApi.verify_connect_cookies_signature(cookies)
      FacebookApi::Session.new(cookies["#{FacebookApi.api_key}_session_key"], cookies["#{FacebookApi.api_key}_user"])
    end
  end

  def require_facebook_session
    unless facebook_session
      redirect_to facebook_connect_path
    end
  end
end

Thanks to Mike Mangino of Facebooker and Travis Reeder of MiniFb for inspiration.

Copyright © 2010 Tekin Suleyman. See LICENSE for details.