Facebook omniauth nil object

Rails 3.1.3

Gemfile
gem 'authbuttons-rails'
gem 'twitter'
gem 'omniauth-twitter'
gem 'omniauth-facebook'

My app needs Facebook integration, and the similar method works for
Twitter API.
When it comes to Facebook, the create method in services_controller.rb
raises an error

  You have a nil object when you didn't expect it!
  You might have expected an instance of Array.
  The error occurred while evaluating nil.[]

  app/models/user.rb:47:in `connect_service'
  app/controllers/services_controller.rb:18:in `create'

Sorry about the length of the code.

Do you see any problem? I believe that I'm making a stupid mistake
because the code got too long...

# and connect_service method in user.rb is

    def connect_service(omniauth)
        #set uid and provider
        case omniauth['provider']
        when 'twitter'
            omniauth['uid'] ? uid = omniauth['uid'] : uid = ''
            omniauth['provider'] ? provider = omniauth['provider'] :
provider = ''
            token = (omniauth['credentials']['token'] rescue nil)
            secret = (omniauth['credentials']['secret'] rescue nil)
        when 'facebook'
            omniauth['extra']['user_hash']['id'] ? uid =
omniauth['extra']['user_hash']['id'] : uid = '' ###HERE!!
            omniauth['provider'] ? provider = omniauth['provider'] :
provider = ''
            token = (omniauth['credentials']['token'] rescue nil)
            secret = ''
        end
        services.build(:provider => provider, :uid => uid, :token =>
token, :secret => secret)
    end

at line 18 where I indicated by putting "###HERE!" in the code
# service controller that creates Twitter and Facebookl things

class ServicesController < ApplicationController
    before_filter :authenticate_user!, :except => [:create]

    def index
        # get all authentication services assigned to the current user
        @services = current_user.services.all
    end

    def create
        # get the full hash from omniauth
        omniauth = request.env['omniauth.auth']
        authentication =
Service.find_by_provider_and_uid(omniauth['provider'], omniauth['uid'])
        if authentication.present?
            flash[:notice] = "Signed in successfully."
            sign_in_and_redirect(:user,authentication.user)
        elsif omniauth.present?
            if user_signed_in?
                current_user.connect_service(omniauth)
                if current_user.save
                    redirect_to services_url, notice: "Authentication
successful."
                else
                    redirect_to root_path, alert: "Error while saving
Authentication information."
                end
            elsif (omniauth['provider'] == "facebook")
                if existinguser =
User.find_by_email(omniauth['extra']['user_hash']['email']) ####HERE!
                    existinguser.connect_service(omniauth)
                    if existinguser.save
                        flash[:notice] = "Signed in successfully."
                        sign_in_and_redirect(:user,existinguser)
                    else
                        redirect_to root_path, alert: "Error while
saving Authentication information."
                    end
                else
                    session[:omniauth] = omniauth
                    redirect_to new_user_registration_url
                end
            else
                session[:omniauth] = omniauth.except('extra')
                redirect_to new_user_registration_url
            end
        else
            redirect_to root_path, alert: "Error while authenticating."
        end
    end

    def destroy
        # remove an authentication service linked to the current user
        @service = current_user.services.find_by_id(params[:id])

        if @service.present?
            @service.destroy
            redirect_to services_path, notice: 'Service was successfully
deleted.'
        else
            redirect_to services_path, alert: 'Service was not found.'
        end
    end
end

soichi

I presume that you meant line 47 in user.rb rather than 18.
That suggests that omniauth['extra'] or omniauth['extra']['user_hash']
is nil. Have a look at the Rails Guide on debugging for ideas on how
to debug this. You could break in here with the debugger or put some
extra tests in the code with puts statements to show the result.

Colin

thanks for your answer.
I finally managed to find the problem.

omniauth['extra']['user_hash']['id'] ? uid =
omniauth['extra']['user_hash']['id'] : uid = ''

should be

omniauth['info']['id'] ? uid =
omniauth['info']['id'] : uid = ''

of course, all the other

"['extra']['user_hash']" parts are now "['info']" due to API changes.

soichi