While there's no officially documented method in the Google+ API way to get a raw share count, there are some tricks you can do to acheive this.
For this example, we're working in a Rails app with Nokogiri. We'll use Nokogiri to open the Google+ fastbutton
tool and return the share count.
require 'open-uri'
require 'nokogiri'
@url = "http://yoursite.com"
googleplus_data = Nokogiri::HTML(open("https://plusone.google.com/_/+1/fastbutton?url=#{@url}"))
self.gplus_count = googleplus_data.css('div#aggregateCount')[0].text.to_i
Thanks 👍