Using Koala to fetch and put data on Facebooks Graph API

facebook.yml

// This is just sample
app_id: 492347987394
secret: erweoryc98b48348753285873624875c83

koala_sample.rb

# Setup on initializers:
module Facebook
  SCOPES = 'manage_pages, pages_show_list, publish_pages'
  CONFIG = YAML.load_file("facebook.yml")
  APP_ID = CONFIG['app_id']
  SECRET = CONFIG['secret']

  class Authentication < Koala::Facebook::OAuth
    def initialize(*args)
      case args.size
      when 0, 1
        raise "application id and/or secret are not specified in the config" unless APP_ID && SECRET
        super(APP_ID.to_s, SECRET.to_s, args.first)
      when 2, 3
        super(*args)
      end
    end
  end
end

# To request for permission for a facebook account, We use the following to generate the url:
Facebook::Authentication.new.url_for_oauth_code(:callback => new_token_url, scope: Facebook::SCOPES, auth_type: 'rerequest')

# in the new token url action, We can get the access token by:
@user_token = Facebook::Authentication.new(new_token_url).get_access_token(params[:code])

# We can then use the user token to get page tokens
@graph = Koala::Facebook::API.new(@user_token)
@items = @graph.get_connections('me', 'accounts')

@page_token  = @items.first['access_token']

# We can check if the token has proper permissions using the perms key
@items.first['perms'] # should include CREATE_CONTENT

# We can then use the page token to fetch data
@page_graph = Koala::Facebook::API.new(@page_token)
@page_graph.get_object('me')
# => {"name"=>"Local Company", "id"=>"1831095567158318"}

# To get the feeds (posts in the page):
@page_graph.get_connections('me', 'feed')

# To specify fields:
@page_graph.get_connections('me', 'feed', fields: 'id, created_time, from')

# To include likes and comments:
FIELDS = 'id, created_time, from, likes.summary(true), comments.summary(true){total_count}'
@page_graph.get_connections('me', 'feed', fields: FIELDS)

# To get a single object:
@page_graph.get_object('1831095567158318_1844481365819738')
@page_graph.get_object('1831095567158318_1844481365819738', fields: FIELDS)

# To include metadata:
@page_graph.get_object('1831095567158318_1844481365819738', fields: FIELDS, metadata: true)
# NOTE: metadata is usefull for inspecting the item

# To get multiple objects:
@page_graph.get_objects(['1831095567158318_1844481365819738', '1831095567158318_1844434542491087'])

# or batch them:
list = ['1831095567158318_1844481365819738', '1831095567158318_1844434542491087']

@page_graph.batch do |graph|
  list.each do |item|
    graph.get_object(item)
  end
end

# Batch can also work like this:
@page_graph.batch do |graph|
  graph.get_objects(['1831095567158318_1844481365819738', '1831095567158318_1844434542491087'])
  graph.get_object('1831095567158318_1844481365819738', fields: FIELDS, metadata: true)
  graph.get_object('me')
end

# You can put data like this:
@page_graph.put_comment('me', 'This is a post')
@page_graph.put_comment('1831095567158318_1844481365819738', 'This is a comment')

# To add/remove like:
@page_graph.put_like('1831095567158318_1844481365819738')
@page_graph.delete_like('1831095567158318_1844481365819738')

# Debugging a Token:
@app_oauth = Koala::Facebook::OAuth.new(Facebook::APP_ID, Facebook::SECRET)
@app_token = @app_oauth.get_app_access_token

@app_graph  = Koala::Facebook::API.new(@app_token)
@debug_data = @app_graph.debug_token(@user_token)

# By debugging data, we can validate if the user allowed the necessary permissions.
# This can check whether the user revokes a permission after allowing it
@debug_data['data']['scopes'] # should contain 'publish_pages', 'manage_pages', 'pages_show_list'

# By debugging data, we can also check the issue date and the expiration date
@debug_data['issued_at']
@debug_data['expires_at']