Just a quick prototype to talk to data.com's sandbox.

Gemfile

# Ruby 1.8.7

source "https://rubygems.org"

gem "json_pure"

group :test do
  gem "rspec"
  gem "vcr"
  gem "webmock"
end

jigsaw_api.rb

require 'open-uri'
require 'json'

class JigsawAPI
  def self.contacts_for_company(company_name, levels=nil)
    done = false
    offset=0
    contacts = {}
    until done do
      response = search_contact(company_name, offset, levels)
      json = JSON.parse(response)
      json['contacts'].each do |contact|
        contacts[contact['contactId']] = contact
      end
      offset += 500
      done = (contacts.count >= json['totalHits'])
    end
    contacts.values
  end

  def self.search_contact(company_name, offset, levels)
    url = "https://sandbox.jigsaw.com/rest/searchContact.json?token=u9o2zjmpk4vy&companyName=#{company_name}&offset=#{offset}"
    url << "&levels=#{levels}" if levels
    open(url).read
  end
end

jigsaw_api_spec.rb

require 'jigsaw_api'
require 'vcr'

VCR.configure do |c|
  c.cassette_library_dir = 'fixtures/vcr_cassettes'
  c.hook_into :webmock
end

describe JigsawAPI do
  it "fetches contacts for Hershey" do
    VCR.use_cassette('hershey-contacts') do
      JigsawAPI.contacts_for_company("Hershey").count.should == 479
    end
  end

  it "fetches C-Level contacts for Hershey" do
    VCR.use_cassette('hershey-c-level') do
      JigsawAPI.contacts_for_company("Hershey", "C-Level").count.should == 12
    end
  end

  it "fetches contacts for Oracle" do
    VCR.use_cassette('oracle-contacts') do
      JigsawAPI.contacts_for_company("Oracle").count.should == 8995
    end
  end

  it "fetched contacts have data" do
    VCR.use_cassette('hershey-contacts') do
      contacts = JigsawAPI.contacts_for_company("Hershey")
      %w(email firstname lastname companyName).each do |field|
        contacts.first.keys.should include field
      end
    end
  end
end