Problem with my if then statements executing

Right now I use an 'after_commit :share_all' on my posts model to call the method below which shares info to facebook and twitter. I'm trying to check if the user has the right authentication provider and if so then to issue the share.

def share_all
   if user.authentications.where(:provider => 'facebook')
     then user.facebook_share(title, content, item_name)
    end
   if user.authentications.where(:provider => 'twitter')
     user.twitter_share(title, content, item_name)
     end
 end

When a user only has a twitter provider the first part still seems t开发者_StackOverflowo execute the user.facebook_share, I think this because I see an error in the log of undefined method `token' for nil:NilClass and then there's no post to twitter. How do I get the first if statement only to execute if there's a 'facebook' provider, and if not move on and execute the second if statement if there's a 'twitter' provider?

def facebook_share(title, content, item_name)
   facebook.feed!(
   :message => "#{title} #{item_name} #{content}"
   )

end

def facebook
  unless @fb_user
    provider = self.authentications.find_by_provider('facebook')
    @fb_user ||= FbGraph::User.me(provider.token)
  end
  @fb_user
end

def twitter
  unless @twitter_user
    provider = self.authentications.find_by_provider('twitter')
    @twitter_user = Twitter::Client.new(:oauth_token => provider.token, :oauth_token_secret =>    provider.secret) rescue nil
  end
  @twitter_user
end

def twitter_share(title, content, item_name)
  twitter.update("#{title} #{item_name} #{content}")
end

I think ActiveRecord is returning an empty array []¹ which is true as far as Ruby² is concerned. I imagine you need something like:

def share_all
  if user.authentications.where(:provider => 'facebook').any?
    user.facebook_share(title, content, item_name)
  end
  ...

<sup>1. Well, actually, an ActiveRecord object with Array-like attributes.
2. Everything except false and nil is true.</sup>