contact_importer.rb

require 'oauth'
require 'oauth2'

class ContactImporter
  def initialize(importer)
    @importer = importer
  end

  def authorize_url
    case @importer
    when 'gmail' then get_gmail_authorize_url
    when 'hotmail' then get_hotmail_authorize_url
    when 'yahoo' then get_yahoo_authorize_url
    end
  end

  def contacts(code, oauth_token = nil, oauth_secret_token = nil)
    case @importer
    when 'gmail' then get_gmail_contacts(code)
    when 'hotmail' then get_hotmail_contacts(code)
    when 'yahoo' then get_yahoo_contacts(code, oauth_token, oauth_secret_token)
    end
  end

  def oauth_token_secret
    @request_token = yahoo_consumer.get_request_token(oauth_callback: "https://#{AppConstants.web_host}/contacts/yahoo/callback")
    @request_token.secret
  end

  private

  def get_gmail_authorize_url
    gmail_client.auth_code.authorize_url(redirect_uri: "https://#{AppConstants.web_host}/contacts/gmail/callback", scope: 'https://www.googleapis.com/auth/contacts.readonly')
  end

  def get_hotmail_authorize_url
    hotmail_client.auth_code.authorize_url(redirect_uri: "https://#{AppConstants.web_host}/contacts/hotmail/callback", scope: 'wl.basic, wl.contacts_emails')
  end

  def get_yahoo_authorize_url
    @request_token ||= yahoo_consumer.get_request_token(oauth_callback: "https://#{AppConstants.web_host}/contacts/yahoo/callback")
    @request_token.authorize_url
  end

  def get_gmail_contacts(code)
    token = gmail_client.auth_code.get_token(code, redirect_uri: "https://#{AppConstants.web_host}/contacts/gmail/callback")
    response = token.get("https://www.google.com/m8/feeds/contacts/default/thin", headers: { 'GData-Version' => '3.0' }, params: { alt: 'json', "max-results" => 1_000 })

    parse_gmail_contacts(response)
  end

  def get_hotmail_contacts(code)
    token = hotmail_client.auth_code.get_token(code, redirect_uri: "https://#{AppConstants.web_host}/contacts/hotmail/callback")
    response = token.get("https://apis.live.net/v5.0/me/contacts")

    parse_hotmail_contacts(response)
  end

  def get_yahoo_contacts(oauth_verifier, oauth_token, oauth_token_secret)
    request_token = OAuth::RequestToken.new(yahoo_consumer, oauth_token, oauth_token_secret)
    access_token = request_token.get_access_token(oauth_verifier: oauth_verifier)

    response = access_token.get('https://social.yahooapis.com/v1/user/me/contacts?format=json')
    parse_yahoo_contacts(response)
  end

  def parse_gmail_contacts(response)
    response = JSON.parse(response.body)
    return [] unless response['feed'] && response['feed']['entry']

    contacts = []
    response['feed']['entry'].each do |entry|
      contact = {}
      if gd_name = entry['gd$name']
        contact[:first_name] = gd_name['gd$givenName']['$t'] if gd_name['gd$givenName']
        contact[:last_name] = gd_name['gd$familyName']['$t'] if gd_name['gd$familyName']
      end
      contact[:email] = entry['gd$email'][0]['address'] if entry['gd$email']

      contacts << contact
    end

    contacts
  end

  def parse_hotmail_contacts(response)
    response = JSON.parse(response.body)

    contacts = []
    response['data'].each do |entry|
      contact = {}
      contact[:first_name] = entry['first_name']
      contact[:last_name] = entry['last_name']
      contact[:email] = entry['emails']['preferred'] if entry['emails']

      contacts << contact
    end

    contacts
  end

  def parse_yahoo_contacts(response)
    response = JSON.parse(response.body)
    return [] unless response['contacts']['contact']

    contacts = []
    response['data'].each do |entry|
      contact = {}
      entry['fields'].each do |field|
        case field['type']
        when 'name'
          contact[:first_name] = field['value']['givenName']
          contact[:last_name] = field['value']['familyName']
        when 'email'
          contact[:email] = field['value']
        end
      end

      contacts << contact
    end

    contacts
  end

  def gmail_client
    @gmail_client ||= OAuth2::Client.new(AppConstants.google_client_id, AppConstants.google_client_secret, site: 'https://accounts.google.com', authorize_url: '/o/oauth2/auth', token_url: '/o/oauth2/token')
  end

  def hotmail_client
    @hotmail_client ||= OAuth2::Client.new(AppConstants.hotmail_client_id, AppConstants.hotmail_client_secret, site: 'https://login.live.com', authorize_url: '/oauth20_authorize.srf', token_url: '/oauth20_token.srf')
  end

  def yahoo_consumer
    @yahoo_consumer ||= OAuth::Consumer.new(AppConstants.yahoo_consumer_key, AppConstants.yahoo_consumer_secret, site: 'https://api.login.yahoo.com', request_token_path: '/oauth/v2/get_request_token', access_token_path: '/oauth/v2/get_token', authorize_path: '/oauth/v2/request_auth')
  end
end

imported_contacts_controller.rb

class ImportedContactsController < ApplicationController
  before_filter :authenticate
  before_filter :assign_contacts, only: :callback
  respond_to :html

  def redirect
    importer = ContactImporter.new(params[:importer])
    session[:oauth_token_secret] = importer.oauth_token_secret if params[:importer] == 'yahoo'

    redirect_to importer.authorize_url
  end

  def callback
    @address_book = AddressBook.create(source: params[:importer], user: current_account.user, imported_contacts_attributes: @contacts)

    respond_with @address_book
  end

  private

  def assign_contacts
    importer = ContactImporter.new(params[:importer])
    @contacts = importer.contacts(params[:code] || params[:oauth_verifier], params[:oauth_token], session[:oauth_token_secret])
  end
end