panchew/facepalm

Facebook integration for Rails & Rack applications

Facepalm

Provides a set of classes, methods, and helpers to ease development of Facebook applications with Rails.

Installation

In order to install Facepalm you should add it to your Gemfile:

gem 'facepalm'

Usage

Requesting Permissions

Facepalm makes it simple to require Facebook authentication to access certain controller actions. You can require user to provide certain permissions to your application:

class PostsController < ApplicationController
  facepalm_authentication :email, :publish_actions, :only => :index

  def index
    ...
  end
end

This code will redirect user to Facebook permission request page if user wasn't authenticated yet.

You can also check user authentication right in your action code and request certain permission if necessary:

class PostsController < ApplicationController
  facepalm_authentication :email, :publish_actions, :only => :index

  def edit
    if facepalm_require_authentication(:email)
      ...
    end
  end
end

Accessing Current User

Current Facebook user data can be accessed using the current_facebook_user method:

class UsersController < ApplicationController
  def profile
    @user = User.find_by_facebook_id(current_facebook_user.uid)
  end
end

This method is also accessible as a view helper.

Application Configuration

In order to use Facepalm you should set a default configuration for your Facebook application. The config file should be placed at RAILS_ROOT/config/facebook.yml

Sample config file:

development:
  app_id: ...
  secret: ...
  namespace: your-app-namespace
  callback_domain: yourdomain.com

test:
  app_id: ...
  secret: ...
  namespace: test
  callback_domain: callback.url

All these attributes attributes can be obtained or defined in your application settings at the Facebook developer page.

Default configuration will be automatically loaded at the first request and won't reload. If you want to change application settings you should restart your application server instance.

Default configuration can be accessed from any parts of your code:

Facepalm::Config.default # => #<Facepalm::Config:0x108c03f38 @config={:secret=>"...", :namespace=>"...", :callback_domain=>"...", :app_id=>...}>

Current configuration is also accessible as a facepalm method in your controller. You can override this method to provide application configuration on a per-request basis:

class PostsController < ApplicationController
  def current_fb_app
    FbApp.find_by_app_id(params[:app_id])
  end

  def facepalm
    if current_fb_app
      Facepalm::Config.new(current_fb_app.attributes)
    else
      Facepalm::Config.default
    end
  end
end

Credits

Big thanks to authors of the Facebooker2 plugin for inspiring me to develop this piece of software. I also copied some code snippets from this project so big thanks to everyone who put their effort to develop Facebooker2.

Copyright & License

Copyright (c) 2011-2012 Aleksey V. Dmitriev.It is free software, and may be redistributed under the terms specified in the LICENSE file.